SeongJae Park [Tue, 12 Dec 2023 19:48:06 +0000 (19:48 +0000)]
selftests/damon: implement a python module for test-purpose DAMON sysfs controls
Patch series "selftests/damon: add Python-written DAMON functionality
tests", v2.
DAMON exports most of its functionality via its sysfs interface. Hence
most DAMON functionality tests could be implemented using the interface.
However, because the interfaces require simple but multiple operations for
many controls, writing all such tests from the scratch could be repetitive
and time consuming.
Implement a minimum DAMON sysfs control module, and a couple of DAMON
functionality tests using the control module. The first test is for
ensuring minimum accuracy of data access monitoring, and the second test
is for finding if a previously found and fixed bug is introduced again.
Note that the DAMON sysfs control module is only for avoiding duplicating
code in tests. For convenient and general control of DAMON, users should
use DAMON user-space tools that developed for the purpose, such as
damo[1].
[1] https://github.com/damonitor/damo
Patches Sequence
----------------
This patchset is constructed with five patches. The first three patches
implement a Python-written test implementation-purpose DAMON sysfs control
module. The implementation is incrementally done in the sequence of the
basic data structure (first patch) first, kdamonds start command (second
patch) next, and finally DAMOS tried bytes update command (third patch).
Then two patches for implementing selftests using the module follows. The
fourth patch implements a basic functionality test of DAMON for working
set estimation accuracy. Finally, the fifth patch implements a corner
case test for a previously found bug.
This patch (of 5):
Implement a python module for DAMON sysfs controls. The module is aimed
to be useful for writing DAMON functionality tests in future.
Nonetheless, this module is only representing a subset of DAMON sysfs
files. Following commits will implement more DAMON sysfs controls.
Link: https://lkml.kernel.org/r/20231212194810.54457-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20231212194810.54457-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Randy Dunlap [Sun, 10 Dec 2023 06:38:39 +0000 (22:38 -0800)]
maple_tree: fix typos/spellos etc
Fix typos/grammar and spellos in documentation.
Link: https://lkml.kernel.org/r/20231210063839.29967-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jiapeng Chong [Fri, 8 Dec 2023 02:04:50 +0000 (10:04 +0800)]
maple_tree: fix warning comparing pointer to 0
Avoid pointer type value compared with 0 to make code clear.
./tools/testing/radix-tree/maple.c:34142:15-16: WARNING comparing pointer to 0.
Link: https://lkml.kernel.org/r/20231208020450.7003-1-jiapeng.chong@linux.alibaba.com
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7696
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ryan Roberts [Thu, 7 Dec 2023 16:12:11 +0000 (16:12 +0000)]
selftests/mm/cow: add tests for anonymous multi-size THP
Add tests similar to the existing PMD-sized THP tests, but which operate
on memory backed by (PTE-mapped) multi-size THP. This reuses all the
existing infrastructure. If the test suite detects that multi-size THP is
not supported by the kernel, the new tests are skipped.
Link: https://lkml.kernel.org/r/20231207161211.2374093-11-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Itaru Kitayama <itaru.kitayama@gmail.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ryan Roberts [Thu, 7 Dec 2023 16:12:10 +0000 (16:12 +0000)]
selftests/mm/cow: generalize do_run_with_thp() helper
do_run_with_thp() prepares (PMD-sized) THP memory into different states
before running tests. With the introduction of multi-size THP, we would
like to reuse this logic to also test those smaller THP sizes. So let's
add a thpsize parameter which tells the function what size THP it should
operate on.
A separate commit will utilize this change to add new tests for multi-size
THP, where available.
Link: https://lkml.kernel.org/r/20231207161211.2374093-10-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Itaru Kitayama <itaru.kitayama@gmail.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ryan Roberts [Thu, 7 Dec 2023 16:12:09 +0000 (16:12 +0000)]
selftests/mm/khugepaged: enlighten for multi-size THP
The `collapse_max_ptes_none` test was previously failing when a THP size
less than PMD-size had enabled="always". The root cause is because the
test faults in 1 page less than the threshold it set for collapsing. But
when THP is enabled always, we "over allocate" and therefore the threshold
is passed, and collapse unexpectedly succeeds.
Solve this by enlightening khugepaged selftest. Add a command line option
to pass in the desired THP size that should be used for all anonymous
allocations. The harness will then explicitly configure a THP size as
requested and modify the `collapse_max_ptes_none` test so that it faults
in the threshold minus the number of pages in the configured THP size. If
no command line option is provided, default to order 0, as per previous
behaviour.
I chose to use an order in the command line interface, since this makes
the interface agnostic of base page size, making it easier to invoke from
run_vmtests.sh.
Link: https://lkml.kernel.org/r/20231207161211.2374093-9-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Itaru Kitayama <itaru.kitayama@gmail.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ryan Roberts [Thu, 7 Dec 2023 16:12:08 +0000 (16:12 +0000)]
selftests/mm: support multi-size THP interface in thp_settings
Save and restore the new per-size hugepage enabled setting, if available
on the running kernel.
Since the number of per-size directories is not fixed, solve this as
simply as possible by catering for a maximum number in the thp_settings
struct (20). Each array index is the order. The value of THP_NEVER is
changed to 0 so that all of these new settings default to THP_NEVER and
the user only needs to fill in the ones they want to enable.
Link: https://lkml.kernel.org/r/20231207161211.2374093-8-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Itaru Kitayama <itaru.kitayama@gmail.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ryan Roberts [Thu, 7 Dec 2023 16:12:07 +0000 (16:12 +0000)]
selftests/mm: factor out thp settings management
The khugepaged test has a useful framework for save/restore/pop/push of
all thp settings via the sysfs interface. This will be useful to
explicitly control multi-size THP settings in other tests, so let's move
it out of khugepaged and into its own thp_settings.[c|h] utility.
Link: https://lkml.kernel.org/r/20231207161211.2374093-7-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Tested-by: Alistair Popple <apopple@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Itaru Kitayama <itaru.kitayama@gmail.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ryan Roberts [Thu, 7 Dec 2023 16:12:06 +0000 (16:12 +0000)]
selftests/mm/kugepaged: restore thp settings at exit
Previously, the saved thp settings would be restored upon a signal or at
the natural end of the test suite. But there are some tests that directly
call exit() upon failure. In this case, the thp settings were not being
restored, which could then influence other tests.
Fix this by installing an atexit() handler to do the actual restore. The
signal handler can now just call exit() and the atexit handler is invoked.
Link: https://lkml.kernel.org/r/20231207161211.2374093-6-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Alistair Popple <apopple@nvidia.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Itaru Kitayama <itaru.kitayama@gmail.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ryan Roberts [Thu, 7 Dec 2023 16:12:05 +0000 (16:12 +0000)]
mm: thp: support allocation of anonymous multi-size THP
Introduce the logic to allow THP to be configured (through the new sysfs
interface we just added) to allocate large folios to back anonymous
memory, which are larger than the base page size but smaller than
PMD-size. We call this new THP extension "multi-size THP" (mTHP).
mTHP continues to be PTE-mapped, but in many cases can still provide
similar benefits to traditional PMD-sized THP: Page faults are
significantly reduced (by a factor of e.g. 4, 8, 16, etc. depending on
the configured order), but latency spikes are much less prominent because
the size of each page isn't as huge as the PMD-sized variant and there is
less memory to clear in each page fault. The number of per-page
operations (e.g. ref counting, rmap management, lru list management) are
also significantly reduced since those ops now become per-folio.
Some architectures also employ TLB compression mechanisms to squeeze more
entries in when a set of PTEs are virtually and physically contiguous and
approporiately aligned. In this case, TLB misses will occur less often.
The new behaviour is disabled by default, but can be enabled at runtime by
writing to /sys/kernel/mm/transparent_hugepage/hugepage-XXkb/enabled (see
documentation in previous commit). The long term aim is to change the
default to include suitable lower orders, but there are some risks around
internal fragmentation that need to be better understood first.
[ryan.roberts@arm.com: resolve some multi-size THP review nits]
Link: https://lkml.kernel.org/r/20231214160251.3574571-1-ryan.roberts@arm.com
Link: https://lkml.kernel.org/r/20231207161211.2374093-5-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Barry Song <v-songbaohua@oppo.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Itaru Kitayama <itaru.kitayama@gmail.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ryan Roberts [Thu, 7 Dec 2023 16:12:04 +0000 (16:12 +0000)]
mm: thp: introduce multi-size THP sysfs interface
In preparation for adding support for anonymous multi-size THP, introduce
new sysfs structure that will be used to control the new behaviours. A
new directory is added under transparent_hugepage for each supported THP
size, and contains an `enabled` file, which can be set to "inherit" (to
inherit the global setting), "always", "madvise" or "never". For now, the
kernel still only supports PMD-sized anonymous THP, so only 1 directory is
populated.
The first half of the change converts transhuge_vma_suitable() and
hugepage_vma_check() so that they take a bitfield of orders for which the
user wants to determine support, and the functions filter out all the
orders that can't be supported, given the current sysfs configuration and
the VMA dimensions. The resulting functions are renamed to
thp_vma_suitable_orders() and thp_vma_allowable_orders() respectively.
Convenience functions that take a single, unencoded order and return a
boolean are also defined as thp_vma_suitable_order() and
thp_vma_allowable_order().
The second half of the change implements the new sysfs interface. It has
been done so that each supported THP size has a `struct thpsize`, which
describes the relevant metadata and is itself a kobject. This is pretty
minimal for now, but should make it easy to add new per-thpsize files to
the interface if needed in future (e.g. per-size defrag). Rather than
keep the `enabled` state directly in the struct thpsize, I've elected to
directly encode it into huge_anon_orders_[always|madvise|inherit]
bitfields since this reduces the amount of work required in
thp_vma_allowable_orders() which is called for every page fault.
See Documentation/admin-guide/mm/transhuge.rst, as modified by this
commit, for details of how the new sysfs interface works.
[ryan.roberts@arm.com: fix build warning when CONFIG_SYSFS is disabled]
Link: https://lkml.kernel.org/r/20231211125320.3997543-1-ryan.roberts@arm.com
Link: https://lkml.kernel.org/r/20231207161211.2374093-4-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Barry Song <v-songbaohua@oppo.com>
Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Itaru Kitayama <itaru.kitayama@gmail.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ryan Roberts [Thu, 7 Dec 2023 16:12:03 +0000 (16:12 +0000)]
mm: non-pmd-mappable, large folios for folio_add_new_anon_rmap()
In preparation for supporting anonymous multi-size THP, improve
folio_add_new_anon_rmap() to allow a non-pmd-mappable, large folio to be
passed to it. In this case, all contained pages are accounted using the
order-0 folio (or base page) scheme.
Link: https://lkml.kernel.org/r/20231207161211.2374093-3-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Yu Zhao <yuzhao@google.com>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Barry Song <v-songbaohua@oppo.com>
Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Itaru Kitayama <itaru.kitayama@gmail.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ryan Roberts [Thu, 7 Dec 2023 16:12:02 +0000 (16:12 +0000)]
mm: allow deferred splitting of arbitrary anon large folios
Patch series "Multi-size THP for anonymous memory", v9.
A series to implement multi-size THP (mTHP) for anonymous memory
(previously called "small-sized THP" and "large anonymous folios").
The objective of this is to improve performance by allocating larger
chunks of memory during anonymous page faults:
1) Since SW (the kernel) is dealing with larger chunks of memory than base
pages, there are efficiency savings to be had; fewer page faults, batched PTE
and RMAP manipulation, reduced lru list, etc. In short, we reduce kernel
overhead. This should benefit all architectures.
2) Since we are now mapping physically contiguous chunks of memory, we can take
advantage of HW TLB compression techniques. A reduction in TLB pressure
speeds up kernel and user space. arm64 systems have 2 mechanisms to coalesce
TLB entries; "the contiguous bit" (architectural) and HPA (uarch).
This version incorporates David's feedback on the core patches (#3, #4)
and adds some RB and TB tags (see change log for details).
By default, the existing behaviour (and performance) is maintained. The
user must explicitly enable multi-size THP to see the performance benefit.
This is done via a new sysfs interface (as recommended by David
Hildenbrand - thanks to David for the suggestion)! This interface is
inspired by the existing per-hugepage-size sysfs interface used by
hugetlb, provides full backwards compatibility with the existing PMD-size
THP interface, and provides a base for future extensibility. See [9] for
detailed discussion of the interface.
This series is based on mm-unstable (
715b67adf4c8).
Prerequisites
=============
I'm removing this section on the basis that I don't believe what we were
previously calling prerequisites are really prerequisites anymore. We
originally defined them when mTHP was a compile-time feature. There is
now a runtime control to opt-in to mTHP; when disabled, correctness and
performance are as before. When enabled, the code is still
correct/robust, but in the absence of the one remaining item (compaction)
there may be a performance impact in some corners. See the old list in
the v8 cover letter at [8]. And a longer explanation of my thinking here
[10].
SUMMARY: I don't think we should hold this series up, waiting for the
items on the prerequisites list. I believe this series should be ready
now so hopefully can be added to mm-unstable for some testing, then
fingers crossed for v6.8.
Testing
=======
The series includes patches for mm selftests to enlighten the cow and
khugepaged tests to explicitly test with multi-size THP, in the same way
that PMD-sized THP is tested. The new tests all pass, and no regressions
are observed in the mm selftest suite. I've also run my usual kernel
compilation and java script benchmarks without any issues.
Refer to my performance numbers posted with v6 [6]. (These are for
multi-size THP only - they do not include the arm64 contpte follow-on
series).
John Hubbard at Nvidia has indicated dramatic 10x performance improvements
for some workloads at [11]. (Observed using v6 of this series as well as
the arm64 contpte series).
Kefeng Wang at Huawei has also indicated he sees improvements at [12] although
there are some latency regressions also.
I've also checked that there is no regression in the write fault path when
mTHP is disabled using a microbenchmark. I ran it for a baseline kernel,
as well as v8 and v9. I repeated on Ampere Altra (bare metal) and Apple
M2 (VM):
| | m2 vm | altra |
|--------------|---------------------|---------------------|
| kernel | mean | std_rel | mean | std_rel |
|--------------|----------|----------|----------|----------|
| baseline | 0.000% | 0.341% | 0.000% | 3.581% |
| anonfolio-v8 | 0.005% | 0.272% | 5.068% | 1.128% |
| anonfolio-v9 | -0.013% | 0.442% | 0.107% | 1.788% |
There is no measurable difference on M2, but altra has a slow down in v8
which is fixed in v9 by moving the THP order check to be inline within
thp_vma_allowable_orders(), as suggested by David.
This patch (of 10):
In preparation for the introduction of anonymous multi-size THP, we would
like to be able to split them when they have unmapped subpages, in order
to free those unused pages under memory pressure. So remove the
artificial requirement that the large folio needed to be at least
PMD-sized.
Link: https://lkml.kernel.org/r/20231207161211.2374093-1-ryan.roberts@arm.com
Link: https://lkml.kernel.org/r/20231207161211.2374093-2-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Yu Zhao <yuzhao@google.com>
Reviewed-by: Yin Fengwei <fengwei.yin@intel.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Barry Song <v-songbaohua@oppo.com>
Tested-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Huang, Ying" <ying.huang@intel.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Itaru Kitayama <itaru.kitayama@gmail.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Yosry Ahmed [Wed, 29 Nov 2023 03:21:53 +0000 (03:21 +0000)]
mm: memcg: restore subtree stats flushing
Stats flushing for memcg currently follows the following rules:
- Always flush the entire memcg hierarchy (i.e. flush the root).
- Only one flusher is allowed at a time. If someone else tries to flush
concurrently, they skip and return immediately.
- A periodic flusher flushes all the stats every 2 seconds.
The reason this approach is followed is because all flushes are serialized
by a global rstat spinlock. On the memcg side, flushing is invoked from
userspace reads as well as in-kernel flushers (e.g. reclaim, refault,
etc). This approach aims to avoid serializing all flushers on the global
lock, which can cause a significant performance hit under high
concurrency.
This approach has the following problems:
- Occasionally a userspace read of the stats of a non-root cgroup will
be too expensive as it has to flush the entire hierarchy [1].
- Sometimes the stats accuracy are compromised if there is an ongoing
flush, and we skip and return before the subtree of interest is
actually flushed, yielding stale stats (by up to 2s due to periodic
flushing). This is more visible when reading stats from userspace,
but can also affect in-kernel flushers.
The latter problem is particulary a concern when userspace reads stats
after an event occurs, but gets stats from before the event. Examples:
- When memory usage / pressure spikes, a userspace OOM handler may look
at the stats of different memcgs to select a victim based on various
heuristics (e.g. how much private memory will be freed by killing
this). Reading stale stats from before the usage spike in this case
may cause a wrongful OOM kill.
- A proactive reclaimer may read the stats after writing to
memory.reclaim to measure the success of the reclaim operation. Stale
stats from before reclaim may give a false negative.
- Reading the stats of a parent and a child memcg may be inconsistent
(child larger than parent), if the flush doesn't happen when the
parent is read, but happens when the child is read.
As for in-kernel flushers, they will occasionally get stale stats. No
regressions are currently known from this, but if there are regressions,
they would be very difficult to debug and link to the source of the
problem.
This patch aims to fix these problems by restoring subtree flushing, and
removing the unified/coalesced flushing logic that skips flushing if there
is an ongoing flush. This change would introduce a significant regression
with global stats flushing thresholds. With per-memcg stats flushing
thresholds, this seems to perform really well. The thresholds protect the
underlying lock from unnecessary contention.
This patch was tested in two ways to ensure the latency of flushing is
up to par, on a machine with 384 cpus:
- A synthetic test with 5000 concurrent workers in 500 cgroups doing
allocations and reclaim, as well as 1000 readers for memory.stat
(variation of [2]). No regressions were noticed in the total runtime.
Note that significant regressions in this test are observed with
global stats thresholds, but not with per-memcg thresholds.
- A synthetic stress test for concurrently reading memcg stats while
memory allocation/freeing workers are running in the background,
provided by Wei Xu [3]. With 250k threads reading the stats every
100ms in 50k cgroups, 99.9% of reads take <= 50us. Less than 0.01%
of reads take more than 1ms, and no reads take more than 100ms.
[1] https://lore.kernel.org/lkml/CABWYdi0c6__rh-K7dcM_pkf9BJdTRtAU08M43KO9ME4-dsgfoQ@mail.gmail.com/
[2] https://lore.kernel.org/lkml/CAJD7tka13M-zVZTyQJYL1iUAYvuQ1fcHbCjcOBZcz6POYTV-4g@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CAAPL-u9D2b=iF5Lf_cRnKxUfkiEe0AMDTu6yhrUAzX0b6a6rDg@mail.gmail.com/
[akpm@linux-foundation.org: fix mm/zswap.c]
[yosryahmed@google.com: remove stats flushing mutex]
Link: https://lkml.kernel.org/r/CAJD7tkZgP3m-VVPn+fF_YuvXeQYK=tZZjJHj=dzD=CcSSpp2qg@mail.gmail.com
Link: https://lkml.kernel.org/r/20231129032154.3710765-6-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Tested-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ivan Babrou <ivan@cloudflare.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutny <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Wei Xu <weixugc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Yosry Ahmed [Wed, 29 Nov 2023 03:21:52 +0000 (03:21 +0000)]
mm: workingset: move the stats flush into workingset_test_recent()
The workingset code flushes the stats in workingset_refault() to get
accurate stats of the eviction memcg. In preparation for more scoped
flushed and passing the eviction memcg to the flush call, move the call to
workingset_test_recent() where we have a pointer to the eviction memcg.
The flush call is sleepable, and cannot be made in an rcu read section.
Hence, minimize the rcu read section by also moving it into
workingset_test_recent(). Furthermore, instead of holding the rcu read
lock throughout workingset_test_recent(), only hold it briefly to get a
ref on the eviction memcg. This allows us to make the flush call after we
get the eviction memcg.
As for workingset_refault(), nothing else there appears to be protected by
rcu. The memcg of the faulted folio (which is not necessarily the same as
the eviction memcg) is protected by the folio lock, which is held from all
callsites. Add a VM_BUG_ON() to make sure this doesn't change from under
us.
No functional change intended.
Link: https://lkml.kernel.org/r/20231129032154.3710765-5-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Tested-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ivan Babrou <ivan@cloudflare.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutny <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Wei Xu <weixugc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Yosry Ahmed [Wed, 29 Nov 2023 03:21:51 +0000 (03:21 +0000)]
mm: memcg: make stats flushing threshold per-memcg
A global counter for the magnitude of memcg stats update is maintained on
the memcg side to avoid invoking rstat flushes when the pending updates
are not significant. This avoids unnecessary flushes, which are not very
cheap even if there isn't a lot of stats to flush. It also avoids
unnecessary lock contention on the underlying global rstat lock.
Make this threshold per-memcg. The scheme is followed where percpu (now
also per-memcg) counters are incremented in the update path, and only
propagated to per-memcg atomics when they exceed a certain threshold.
This provides two benefits: (a) On large machines with a lot of memcgs,
the global threshold can be reached relatively fast, so guarding the
underlying lock becomes less effective. Making the threshold per-memcg
avoids this.
(b) Having a global threshold makes it hard to do subtree flushes, as we
cannot reset the global counter except for a full flush. Per-memcg
counters removes this as a blocker from doing subtree flushes, which helps
avoid unnecessary work when the stats of a small subtree are needed.
Nothing is free, of course. This comes at a cost: (a) A new per-cpu
counter per memcg, consuming NR_CPUS * NR_MEMCGS * 4 bytes. The extra
memory usage is insigificant.
(b) More work on the update side, although in the common case it will only
be percpu counter updates. The amount of work scales with the number of
ancestors (i.e. tree depth). This is not a new concept, adding a cgroup
to the rstat tree involves a parent loop, so is charging. Testing results
below show no significant regressions.
(c) The error margin in the stats for the system as a whole increases from
NR_CPUS * MEMCG_CHARGE_BATCH to NR_CPUS * MEMCG_CHARGE_BATCH * NR_MEMCGS.
This is probably fine because we have a similar per-memcg error in charges
coming from percpu stocks, and we have a periodic flusher that makes sure
we always flush all the stats every 2s anyway.
This patch was tested to make sure no significant regressions are
introduced on the update path as follows. The following benchmarks were
ran in a cgroup that is 2 levels deep (/sys/fs/cgroup/a/b/):
(1) Running 22 instances of netperf on a 44 cpu machine with
hyperthreading disabled. All instances are run in a level 2 cgroup, as
well as netserver:
# netserver -6
# netperf -6 -H ::1 -l 60 -t TCP_SENDFILE -- -m 10K
Averaging 20 runs, the numbers are as follows:
Base: 40198.0 mbps
Patched: 38629.7 mbps (-3.9%)
The regression is minimal, especially for 22 instances in the same
cgroup sharing all ancestors (so updating the same atomics).
(2) will-it-scale page_fault tests. These tests (specifically
per_process_ops in page_fault3 test) detected a 25.9% regression before
for a change in the stats update path [1]. These are the
numbers from 10 runs (+ is good) on a machine with 256 cpus:
LABEL | MEAN | MEDIAN | STDDEV |
------------------------------+-------------+-------------+-------------
page_fault1_per_process_ops | | | |
(A) base | 270249.164 | 265437.000 | 13451.836 |
(B) patched | 261368.709 | 255725.000 | 13394.767 |
| -3.29% | -3.66% | |
page_fault1_per_thread_ops | | | |
(A) base | 242111.345 | 239737.000 | 10026.031 |
(B) patched | 237057.109 | 235305.000 | 9769.687 |
| -2.09% | -1.85% | |
page_fault1_scalability | | |
(A) base | 0.034387 | 0.035168 | 0.
0018283 |
(B) patched | 0.033988 | 0.034573 | 0.
0018056 |
| -1.16% | -1.69% | |
page_fault2_per_process_ops | | |
(A) base | 203561.836 | 203301.000 | 2550.764 |
(B) patched | 197195.945 | 197746.000 | 2264.263 |
| -3.13% | -2.73% | |
page_fault2_per_thread_ops | | |
(A) base | 171046.473 | 170776.000 | 1509.679 |
(B) patched | 166626.327 | 166406.000 | 768.753 |
| -2.58% | -2.56% | |
page_fault2_scalability | | |
(A) base | 0.054026 | 0.053821 | 0.
00062121 |
(B) patched | 0.053329 | 0.05306 | 0.
00048394 |
| -1.29% | -1.41% | |
page_fault3_per_process_ops | | |
(A) base |
1295807.782 |
1297550.000 | 5907.585 |
(B) patched |
1275579.873 |
1273359.000 | 8759.160 |
| -1.56% | -1.86% | |
page_fault3_per_thread_ops | | |
(A) base | 391234.164 | 390860.000 | 1760.720 |
(B) patched | 377231.273 | 376369.000 | 1874.971 |
| -3.58% | -3.71% | |
page_fault3_scalability | | |
(A) base | 0.60369 | 0.60072 | 0.
0083029 |
(B) patched | 0.61733 | 0.61544 | 0.009855 |
| +2.26% | +2.45% | |
All regressions seem to be minimal, and within the normal variance for the
benchmark. The fix for [1] assumes that 3% is noise -- and there were no
further practical complaints), so hopefully this means that such
variations in these microbenchmarks do not reflect on practical workloads.
(3) I also ran stress-ng in a nested cgroup and did not observe any
obvious regressions.
[1]https://lore.kernel.org/all/
20190520063534.GB19312@shao2-debian/
Link: https://lkml.kernel.org/r/20231129032154.3710765-4-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ivan Babrou <ivan@cloudflare.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutny <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Wei Xu <weixugc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Yosry Ahmed [Wed, 29 Nov 2023 03:21:50 +0000 (03:21 +0000)]
mm: memcg: move vmstats structs definition above flushing code
The following patch will make use of those structs in the flushing code,
so move their definitions (and a few other dependencies) a little bit up
to reduce the diff noise in the following patch.
No functional change intended.
Link: https://lkml.kernel.org/r/20231129032154.3710765-3-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Tested-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ivan Babrou <ivan@cloudflare.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutny <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Wei Xu <weixugc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Yosry Ahmed [Wed, 29 Nov 2023 03:21:49 +0000 (03:21 +0000)]
mm: memcg: change flush_next_time to flush_last_time
Patch series "mm: memcg: subtree stats flushing and thresholds", v4.
This series attempts to address shortages in today's approach for memcg
stats flushing, namely occasionally stale or expensive stat reads. The
series does so by changing the threshold that we use to decide whether to
trigger a flush to be per memcg instead of global (patch 3), and then
changing flushing to be per memcg (i.e. subtree flushes) instead of
global (patch 5).
This patch (of 5):
flush_next_time is an inaccurate name. It's not the next time that
periodic flushing will happen, it's rather the next time that ratelimited
flushing can happen if the periodic flusher is late.
Simplify its semantics by just storing the timestamp of the last flush
instead, flush_last_time. Move the 2*FLUSH_TIME addition to
mem_cgroup_flush_stats_ratelimited(), and add a comment explaining it.
This way, all the ratelimiting semantics live in one place.
No functional change intended.
Link: https://lkml.kernel.org/r/20231129032154.3710765-1-yosryahmed@google.com
Link: https://lkml.kernel.org/r/20231129032154.3710765-2-yosryahmed@google.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Tested-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Chris Li <chrisl@kernel.org> (Google)
Tested-by: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Ivan Babrou <ivan@cloudflare.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutny <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: Waiman Long <longman@redhat.com>
Cc: Wei Xu <weixugc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Andrew Morton [Thu, 14 Dec 2023 15:32:58 +0000 (07:32 -0800)]
mm/list_lru.c: remove unused list_lru_from_kmem()
Fixes:
0a97c01cd20bb ("list_lru: allow explicit memcg and NUMA node selection)
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/
202312141318.q8b5yrAq-lkp@intel.com/
Cc: Nhat Pham <nphamcs@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Andrew Morton [Wed, 13 Dec 2023 20:59:49 +0000 (12:59 -0800)]
lib/maple_tree.c: fix build error due to hotfix alteration
Commit
0de56e38b307 ("maple_tree: use maple state end for write
operations") was broken by a later patch "maple_tree: do not preallocate
nodes for slot stores". But the later patch was scheduled ahead of
0de56e38b307, for 6.7-rc.
This fixlet undoes the damage.
Fixes:
0de56e38b307 ("maple_tree: use maple state end for write operations")
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Andrew Morton [Wed, 20 Dec 2023 22:47:18 +0000 (14:47 -0800)]
sync mm-stable with mm-hotfixes-stable to pick up depended-upon changes
Matthew Wilcox (Oracle) [Mon, 18 Dec 2023 14:03:28 +0000 (14:03 +0000)]
mailmap: add an old address for Naoya Horiguchi
This address now bounces, remap it to a current address.
Link: https://lkml.kernel.org/r/20231218140328.3313474-1-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Matthew Wilcox (Oracle) [Mon, 18 Dec 2023 13:58:37 +0000 (13:58 +0000)]
mm/memory-failure: cast index to loff_t before shifting it
On 32-bit systems, we'll lose the top bits of index because arithmetic
will be performed in unsigned long instead of unsigned long long. This
affects files over 4GB in size.
Link: https://lkml.kernel.org/r/20231218135837.3310403-4-willy@infradead.org
Fixes:
6100e34b2526 ("mm, memory_failure: Teach memory_failure() about dev_pagemap pages")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Matthew Wilcox (Oracle) [Mon, 18 Dec 2023 13:58:36 +0000 (13:58 +0000)]
mm/memory-failure: check the mapcount of the precise page
A process may map only some of the pages in a folio, and might be missed
if it maps the poisoned page but not the head page. Or it might be
unnecessarily hit if it maps the head page, but not the poisoned page.
Link: https://lkml.kernel.org/r/20231218135837.3310403-3-willy@infradead.org
Fixes:
7af446a841a2 ("HWPOISON, hugetlb: enable error handling path for hugepage")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Matthew Wilcox (Oracle) [Mon, 18 Dec 2023 13:58:35 +0000 (13:58 +0000)]
mm/memory-failure: pass the folio and the page to collect_procs()
Patch series "Three memory-failure fixes".
I've been looking at the memory-failure code and I believe I have found
three bugs that need fixing -- one going all the way back to 2010! I'll
have more patches later to use folios more extensively but didn't want
these bugfixes to get caught up in that.
This patch (of 3):
Both collect_procs_anon() and collect_procs_file() iterate over the VMA
interval trees looking for a single pgoff, so it is wrong to look for the
pgoff of the head page as is currently done. However, it is also wrong to
look at page->mapping of the precise page as this is invalid for tail
pages. Clear up the confusion by passing both the folio and the precise
page to collect_procs().
Link: https://lkml.kernel.org/r/20231218135837.3310403-1-willy@infradead.org
Link: https://lkml.kernel.org/r/20231218135837.3310403-2-willy@infradead.org
Fixes:
415c64c1453a ("mm/memory-failure: split thp earlier in memory error handling")
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Muhammad Usama Anjum [Thu, 14 Dec 2023 10:19:30 +0000 (15:19 +0500)]
selftests: secretmem: floor the memory size to the multiple of page_size
The "locked-in-memory size" limit per process can be non-multiple of
page_size. The mmap() fails if we try to allocate locked-in-memory with
same size as the allowed limit if it isn't multiple of the page_size
because mmap() rounds off the memory size to be allocated to next multiple
of page_size.
Fix this by flooring the length to be allocated with mmap() to the
previous multiple of the page_size.
This was getting triggered on KernelCI regularly because of different
ulimit settings which wasn't multiple of the page_size. Find logs
here: https://linux.kernelci.org/test/plan/id/
657654bd8e81e654fae13532/
The bug in was present from the time test was first added.
Link: https://lkml.kernel.org/r/20231214101931.1155586-1-usama.anjum@collabora.com
Fixes:
76fe17ef588a ("secretmem: test: add basic selftest for memfd_secret(2)")
Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Reported-by: "kernelci.org bot" <bot@kernelci.org>
Closes: https://linux.kernelci.org/test/plan/id/
657654bd8e81e654fae13532/
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Charan Teja Kalla [Thu, 14 Dec 2023 04:58:41 +0000 (04:58 +0000)]
mm: migrate high-order folios in swap cache correctly
Large folios occupy N consecutive entries in the swap cache instead of
using multi-index entries like the page cache. However, if a large folio
is re-added to the LRU list, it can be migrated. The migration code was
not aware of the difference between the swap cache and the page cache and
assumed that a single xas_store() would be sufficient.
This leaves potentially many stale pointers to the now-migrated folio in
the swap cache, which can lead to almost arbitrary data corruption in the
future. This can also manifest as infinite loops with the RCU read lock
held.
[willy@infradead.org: modifications to the changelog & tweaked the fix]
Fixes:
3417013e0d18 ("mm/migrate: Add folio_migrate_mapping()")
Link: https://lkml.kernel.org/r/20231214045841.961776-1-willy@infradead.org
Signed-off-by: Charan Teja Kalla <quic_charante@quicinc.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reported-by: Charan Teja Kalla <quic_charante@quicinc.com>
Closes: https://lkml.kernel.org/r/
1700569840-17327-1-git-send-email-quic_charante@quicinc.com
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Sidhartha Kumar [Wed, 13 Dec 2023 20:50:57 +0000 (12:50 -0800)]
maple_tree: do not preallocate nodes for slot stores
mas_preallocate() defaults to requesting 1 node for preallocation and then
,depending on the type of store, will update the request variable. There
isn't a check for a slot store type, so slot stores are preallocating the
default 1 node. Slot stores do not require any additional nodes, so add a
check for the slot store case that will bypass node_count_gfp(). Update
the tests to reflect that slot stores do not require allocations.
User visible effects of this bug include increased memory usage from the
unneeded node that was allocated.
Link: https://lkml.kernel.org/r/20231213205058.386589-1-sidhartha.kumar@oracle.com
Fixes:
0b8bb544b1a7 ("maple_tree: update mas_preallocate() testing")
Signed-off-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: <stable@vger.kernel.org> [6.6+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Baokun Li [Wed, 13 Dec 2023 06:23:24 +0000 (14:23 +0800)]
mm/filemap: avoid buffered read/write race to read inconsistent data
The following concurrency may cause the data read to be inconsistent with
the data on disk:
cpu1 cpu2
------------------------------|------------------------------
// Buffered write 2048 from 0
ext4_buffered_write_iter
generic_perform_write
copy_page_from_iter_atomic
ext4_da_write_end
ext4_da_do_write_end
block_write_end
__block_commit_write
folio_mark_uptodate
// Buffered read 4096 from 0 smp_wmb()
ext4_file_read_iter set_bit(PG_uptodate, folio_flags)
generic_file_read_iter i_size_write // 2048
filemap_read unlock_page(page)
filemap_get_pages
filemap_get_read_batch
folio_test_uptodate(folio)
ret = test_bit(PG_uptodate, folio_flags)
if (ret)
smp_rmb();
// Ensure that the data in page 0-2048 is up-to-date.
// New buffered write 2048 from 2048
ext4_buffered_write_iter
generic_perform_write
copy_page_from_iter_atomic
ext4_da_write_end
ext4_da_do_write_end
block_write_end
__block_commit_write
folio_mark_uptodate
smp_wmb()
set_bit(PG_uptodate, folio_flags)
i_size_write // 4096
unlock_page(page)
isize = i_size_read(inode) // 4096
// Read the latest isize 4096, but without smp_rmb(), there may be
// Load-Load disorder resulting in the data in the 2048-4096 range
// in the page is not up-to-date.
copy_page_to_iter
// copyout 4096
In the concurrency above, we read the updated i_size, but there is no read
barrier to ensure that the data in the page is the same as the i_size at
this point, so we may copy the unsynchronized page out. Hence adding the
missing read memory barrier to fix this.
This is a Load-Load reordering issue, which only occurs on some weak
mem-ordering architectures (e.g. ARM64, ALPHA), but not on strong
mem-ordering architectures (e.g. X86). And theoretically the problem
doesn't only happen on ext4, filesystems that call filemap_read() but
don't hold inode lock (e.g. btrfs, f2fs, ubifs ...) will have this
problem, while filesystems with inode lock (e.g. xfs, nfs) won't have
this problem.
Link: https://lkml.kernel.org/r/20231213062324.739009-1-libaokun1@huawei.com
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Andreas Dilger <adilger.kernel@dilger.ca>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Cc: Theodore Ts'o <tytso@mit.edu>
Cc: yangerkun <yangerkun@huawei.com>
Cc: Yu Kuai <yukuai3@huawei.com>
Cc: Zhang Yi <yi.zhang@huawei.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Nico Pache [Tue, 12 Dec 2023 23:26:59 +0000 (16:26 -0700)]
kunit: kasan_test: disable fortify string checker on kmalloc_oob_memset
Similar to commit
09c6304e38e4 ("kasan: test: fix compatibility with
FORTIFY_SOURCE") the kernel is panicing in kmalloc_oob_memset_*.
This is due to the `ptr` not being hidden from the optimizer which would
disable the runtime fortify string checker.
kernel BUG at lib/string_helpers.c:1048!
Call Trace:
[<
00000000272502e2>] fortify_panic+0x2a/0x30
([<
00000000272502de>] fortify_panic+0x26/0x30)
[<
001bffff817045c4>] kmalloc_oob_memset_2+0x22c/0x230 [kasan_test]
Hide the `ptr` variable from the optimizer to fix the kernel panic. Also
define a memset_size variable and hide that as well. This cleans up the
code and follows the same convention as other tests.
[npache@redhat.com: address review comments from Andrey]
Link: https://lkml.kernel.org/r/20231214164423.6202-1-npache@redhat.com
Link: https://lkml.kernel.org/r/20231212232659.18839-1-npache@redhat.com
Signed-off-by: Nico Pache <npache@redhat.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Vincenzo Frascino <vincenzo.frascino@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Arnd Bergmann [Mon, 23 Oct 2023 11:01:55 +0000 (13:01 +0200)]
kexec: select CRYPTO from KEXEC_FILE instead of depending on it
All other users of crypto code use 'select' instead of 'depends on', so do
the same thing with KEXEC_FILE for consistency.
In practice this makes very little difference as kernels with kexec
support are very likely to also include some other feature that already
selects both crypto and crypto_sha256, but being consistent here helps for
usability as well as to avoid potential circular dependencies.
This reverts the dependency back to what it was originally before commit
74ca317c26a3f ("kexec: create a new config option CONFIG_KEXEC_FILE for
new syscall"), which changed changed it with the comment "This should be
safer as "select" is not recursive", but that appears to have been done in
error, as "select" is indeed recursive, and there are no other
dependencies that prevent CRYPTO_SHA256 from being selected here.
Link: https://lkml.kernel.org/r/20231023110308.1202042-2-arnd@kernel.org
Fixes:
74ca317c26a3f ("kexec: create a new config option CONFIG_KEXEC_FILE for new syscall")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Eric DeVolder <eric_devolder@yahoo.com>
Tested-by: Eric DeVolder <eric_devolder@yahoo.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Conor Dooley <conor@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Arnd Bergmann [Mon, 23 Oct 2023 11:01:54 +0000 (13:01 +0200)]
kexec: fix KEXEC_FILE dependencies
The cleanup for the CONFIG_KEXEC Kconfig logic accidentally changed the
'depends on CRYPTO=y' dependency to a plain 'depends on CRYPTO', which
causes a link failure when all the crypto support is in a loadable module
and kexec_file support is built-in:
x86_64-linux-ld: vmlinux.o: in function `__x64_sys_kexec_file_load':
(.text+0x32e30a): undefined reference to `crypto_alloc_shash'
x86_64-linux-ld: (.text+0x32e58e): undefined reference to `crypto_shash_update'
x86_64-linux-ld: (.text+0x32e6ee): undefined reference to `crypto_shash_final'
Both s390 and x86 have this problem, while ppc64 and riscv have the
correct dependency already. On riscv, the dependency is only used for the
purgatory, not for the kexec_file code itself, which may be a bit
surprising as it means that with CONFIG_CRYPTO=m, it is possible to enable
KEXEC_FILE but then the purgatory code is silently left out.
Move this into the common Kconfig.kexec file in a way that is correct
everywhere, using the dependency on CRYPTO_SHA256=y only when the
purgatory code is available. This requires reversing the dependency
between ARCH_SUPPORTS_KEXEC_PURGATORY and KEXEC_FILE, but the effect
remains the same, other than making riscv behave like the other ones.
On s390, there is an additional dependency on CRYPTO_SHA256_S390, which
should technically not be required but gives better performance. Remove
this dependency here, noting that it was not present in the initial
Kconfig code but was brought in without an explanation in commit
71406883fd357 ("s390/kexec_file: Add kexec_file_load system call").
[arnd@arndb.de: fix riscv build]
Link: https://lkml.kernel.org/r/67ddd260-d424-4229-a815-e3fcfb864a77@app.fastmail.com
Link: https://lkml.kernel.org/r/20231023110308.1202042-1-arnd@kernel.org
Fixes:
6af5138083005 ("x86/kexec: refactor for kernel/Kconfig.kexec")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Eric DeVolder <eric_devolder@yahoo.com>
Tested-by: Eric DeVolder <eric_devolder@yahoo.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Conor Dooley <conor@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Yu Zhao [Fri, 8 Dec 2023 06:14:07 +0000 (23:14 -0700)]
mm/mglru: reclaim offlined memcgs harder
In the effort to reduce zombie memcgs [1], it was discovered that the
memcg LRU doesn't apply enough pressure on offlined memcgs. Specifically,
instead of rotating them to the tail of the current generation
(MEMCG_LRU_TAIL) for a second attempt, it moves them to the next
generation (MEMCG_LRU_YOUNG) after the first attempt.
Not applying enough pressure on offlined memcgs can cause them to build
up, and this can be particularly harmful to memory-constrained systems.
On Pixel 8 Pro, launching apps for 50 cycles:
Before After Change
Zombie memcgs 45 35 -22%
[1] https://lore.kernel.org/CABdmKX2M6koq4Q0Cmp_-=wbP0Qa190HdEGGaHfxNS05gAkUtPA@mail.gmail.com/
Link: https://lkml.kernel.org/r/20231208061407.2125867-4-yuzhao@google.com
Fixes:
e4dde56cd208 ("mm: multi-gen LRU: per-node lru_gen_folio lists")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reported-by: T.J. Mercier <tjmercier@google.com>
Tested-by: T.J. Mercier <tjmercier@google.com>
Cc: Charan Teja Kalla <quic_charante@quicinc.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jaroslav Pulchart <jaroslav.pulchart@gooddata.com>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Yu Zhao [Fri, 8 Dec 2023 06:14:06 +0000 (23:14 -0700)]
mm/mglru: respect min_ttl_ms with memcgs
While investigating kswapd "consuming 100% CPU" [1] (also see "mm/mglru:
try to stop at high watermarks"), it was discovered that the memcg LRU can
breach the thrashing protection imposed by min_ttl_ms.
Before the memcg LRU:
kswapd()
shrink_node_memcgs()
mem_cgroup_iter()
inc_max_seq() // always hit a different memcg
lru_gen_age_node()
mem_cgroup_iter()
check the timestamp of the oldest generation
After the memcg LRU:
kswapd()
shrink_many()
restart:
iterate the memcg LRU:
inc_max_seq() // occasionally hit the same memcg
if raced with lru_gen_rotate_memcg():
goto restart
lru_gen_age_node()
mem_cgroup_iter()
check the timestamp of the oldest generation
Specifically, when the restart happens in shrink_many(), it needs to stick
with the (memcg LRU) generation it began with. In other words, it should
neither re-read memcg_lru->seq nor age an lruvec of a different
generation. Otherwise it can hit the same memcg multiple times without
giving lru_gen_age_node() a chance to check the timestamp of that memcg's
oldest generation (against min_ttl_ms).
[1] https://lore.kernel.org/CAK8fFZ4DY+GtBA40Pm7Nn5xCHy+51w3sfxPqkqpqakSXYyX+Wg@mail.gmail.com/
Link: https://lkml.kernel.org/r/20231208061407.2125867-3-yuzhao@google.com
Fixes:
e4dde56cd208 ("mm: multi-gen LRU: per-node lru_gen_folio lists")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Tested-by: T.J. Mercier <tjmercier@google.com>
Cc: Charan Teja Kalla <quic_charante@quicinc.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jaroslav Pulchart <jaroslav.pulchart@gooddata.com>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Kalesh Singh <kaleshsingh@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Yu Zhao [Fri, 8 Dec 2023 06:14:05 +0000 (23:14 -0700)]
mm/mglru: try to stop at high watermarks
The initial MGLRU patchset didn't include the memcg LRU support, and it
relied on should_abort_scan(), added by commit
f76c83378851 ("mm:
multi-gen LRU: optimize multiple memcgs"), to "backoff to avoid
overshooting their aggregate reclaim target by too much".
Later on when the memcg LRU was added, should_abort_scan() was deemed
unnecessary, and the test results [1] showed no side effects after it was
removed by commit
a579086c99ed ("mm: multi-gen LRU: remove eviction
fairness safeguard").
However, that test used memory.reclaim, which sets nr_to_reclaim to
SWAP_CLUSTER_MAX. So it can overshoot only by SWAP_CLUSTER_MAX-1 pages,
i.e., from nr_reclaimed=nr_to_reclaim-1 to
nr_reclaimed=nr_to_reclaim+SWAP_CLUSTER_MAX-1. Compared with the batch
size kswapd sets to nr_to_reclaim, SWAP_CLUSTER_MAX is tiny. Therefore
that test isn't able to reproduce the worst case scenario, i.e., kswapd
overshooting GBs on large systems and "consuming 100% CPU" (see the Closes
tag).
Bring back a simplified version of should_abort_scan() on top of the memcg
LRU, so that kswapd stops when all eligible zones are above their
respective high watermarks plus a small delta to lower the chance of
KSWAPD_HIGH_WMARK_HIT_QUICKLY. Note that this only applies to order-0
reclaim, meaning compaction-induced reclaim can still run wild (which is a
different problem).
On Android, launching 55 apps sequentially:
Before After Change
pgpgin
838377172 802955040 -4%
pgpgout
38037080 34336300 -10%
[1] https://lore.kernel.org/
20221222041905.
2431096-1-yuzhao@google.com/
Link: https://lkml.kernel.org/r/20231208061407.2125867-2-yuzhao@google.com
Fixes:
a579086c99ed ("mm: multi-gen LRU: remove eviction fairness safeguard")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reported-by: Charan Teja Kalla <quic_charante@quicinc.com>
Reported-by: Jaroslav Pulchart <jaroslav.pulchart@gooddata.com>
Closes: https://lore.kernel.org/CAK8fFZ4DY+GtBA40Pm7Nn5xCHy+51w3sfxPqkqpqakSXYyX+Wg@mail.gmail.com/
Tested-by: Jaroslav Pulchart <jaroslav.pulchart@gooddata.com>
Tested-by: Kalesh Singh <kaleshsingh@google.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: T.J. Mercier <tjmercier@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Yu Zhao [Fri, 8 Dec 2023 06:14:04 +0000 (23:14 -0700)]
mm/mglru: fix underprotected page cache
Unmapped folios accessed through file descriptors can be underprotected.
Those folios are added to the oldest generation based on:
1. The fact that they are less costly to reclaim (no need to walk the
rmap and flush the TLB) and have less impact on performance (don't
cause major PFs and can be non-blocking if needed again).
2. The observation that they are likely to be single-use. E.g., for
client use cases like Android, its apps parse configuration files
and store the data in heap (anon); for server use cases like MySQL,
it reads from InnoDB files and holds the cached data for tables in
buffer pools (anon).
However, the oldest generation can be very short lived, and if so, it
doesn't provide the PID controller with enough time to respond to a surge
of refaults. (Note that the PID controller uses weighted refaults and
those from evicted generations only take a half of the whole weight.) In
other words, for a short lived generation, the moving average smooths out
the spike quickly.
To fix the problem:
1. For folios that are already on LRU, if they can be beyond the
tracking range of tiers, i.e., five accesses through file
descriptors, move them to the second oldest generation to give them
more time to age. (Note that tiers are used by the PID controller
to statistically determine whether folios accessed multiple times
through file descriptors are worth protecting.)
2. When adding unmapped folios to LRU, adjust the placement of them so
that they are not too close to the tail. The effect of this is
similar to the above.
On Android, launching 55 apps sequentially:
Before After Change
workingset_refault_anon
25641024 25598972 0%
workingset_refault_file
115016834 106178438 -8%
Link: https://lkml.kernel.org/r/20231208061407.2125867-1-yuzhao@google.com
Fixes:
ac35a4902374 ("mm: multi-gen LRU: minimal implementation")
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reported-by: Charan Teja Kalla <quic_charante@quicinc.com>
Tested-by: Kalesh Singh <kaleshsingh@google.com>
Cc: T.J. Mercier <tjmercier@google.com>
Cc: Kairui Song <ryncsn@gmail.com>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Jaroslav Pulchart <jaroslav.pulchart@gooddata.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Stevens [Tue, 18 Apr 2023 08:40:31 +0000 (17:40 +0900)]
mm/shmem: fix race in shmem_undo_range w/THP
Split folios during the second loop of shmem_undo_range. It's not
sufficient to only split folios when dealing with partial pages, since
it's possible for a THP to be faulted in after that point. Calling
truncate_inode_folio in that situation can result in throwing away data
outside of the range being targeted.
[akpm@linux-foundation.org: tidy up comment layout]
Link: https://lkml.kernel.org/r/20230418084031.3439795-1-stevensd@google.com
Fixes:
b9a8a4195c7d ("truncate,shmem: Handle truncates that split large folios")
Signed-off-by: David Stevens <stevensd@chromium.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Suleiman Souhlal <suleiman@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
John Hubbard [Sat, 9 Dec 2023 02:01:44 +0000 (18:01 -0800)]
Revert "selftests: error out if kernel header files are not yet built"
This reverts commit
9fc96c7c19df ("selftests: error out if kernel header
files are not yet built").
It turns out that requiring the kernel headers to be built as a
prerequisite to building selftests, does not work in many cases. For
example, Peter Zijlstra writes:
"My biggest beef with the whole thing is that I simply do not want to use
'make headers', it doesn't work for me.
I have a ton of output directories and I don't care to build tools into
the output dirs, in fact some of them flat out refuse to work that way
(bpf comes to mind)." [1]
Therefore, stop erroring out on the selftests build. Additional patches
will be required in order to change over to not requiring the kernel
headers.
[1] https://lore.kernel.org/
20231208221007.GO28727@noisy.programming.kicks-ass.net
Link: https://lkml.kernel.org/r/20231209020144.244759-1-jhubbard@nvidia.com
Fixes:
9fc96c7c19df ("selftests: error out if kernel header files are not yet built")
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Cc: Anders Roxell <anders.roxell@linaro.org>
Cc: Muhammad Usama Anjum <usama.anjum@collabora.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Marcos Paulo de Souza <mpdesouza@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Yuntao Wang [Sat, 9 Dec 2023 14:14:38 +0000 (22:14 +0800)]
crash_core: fix the check for whether crashkernel is from high memory
If crash_base is equal to CRASH_ADDR_LOW_MAX, it also indicates that
the crashkernel memory is allocated from high memory. However, the
current check only considers the case where crash_base is greater than
CRASH_ADDR_LOW_MAX. Fix it.
The runtime effects is that crashkernel high memory is successfully
reserved, whereas the crashkernel low memory is bypassed in this case,
then kdump kernel bootup will fail because of no low memory under 4G.
This patch also includes some minor cleanups.
Link: https://lkml.kernel.org/r/20231209141438.77233-1-ytcoode@gmail.com
Fixes:
0ab97169aa05 ("crash_core: add generic function to do reservation")
Signed-off-by: Yuntao Wang <ytcoode@gmail.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Zhen Lei <thunder.leizhen@huawei.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Baoquan He [Fri, 8 Dec 2023 07:30:36 +0000 (15:30 +0800)]
x86, kexec: fix the wrong ifdeffery CONFIG_KEXEC
With the current ifdeffery CONFIG_KEXEC, get_cmdline_acpi_rsdp() is only
available when kexec_load interface is taken, while kexec_file_load
interface can't make use of it.
Now change it to CONFIG_KEXEC_CORE.
Link: https://lkml.kernel.org/r/20231208073036.7884-6-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Eric DeVolder <eric_devolder@yahoo.com>
Cc: Ignat Korchagin <ignat@cloudflare.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Baoquan He [Fri, 8 Dec 2023 07:30:35 +0000 (15:30 +0800)]
sh, kexec: fix the incorrect ifdeffery and dependency of CONFIG_KEXEC
The select of KEXEC for CRASH_DUMP in kernel/Kconfig.kexec will be
dropped, then compiling errors will be triggered if below config
items are set:
===
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_CRASH_DUMP=y
===
Here, change the dependency of building kexec_core related object files,
and the ifdeffery on SuperH from CONFIG_KEXEC to CONFIG_KEXEC_CORE.
Link: https://lkml.kernel.org/r/20231208073036.7884-5-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Eric DeVolder <eric_devolder@yahoo.com>
Cc: Ignat Korchagin <ignat@cloudflare.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Baoquan He [Fri, 8 Dec 2023 07:30:34 +0000 (15:30 +0800)]
mips, kexec: fix the incorrect ifdeffery and dependency of CONFIG_KEXEC
The select of KEXEC for CRASH_DUMP in kernel/Kconfig.kexec will be
dropped, then compiling errors will be triggered if below config items are
set:
===
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_CRASH_DUMP=y
===
--------------------------------------------------------------------
mipsel-linux-ld: kernel/kexec_core.o: in function `kimage_free':
kernel/kexec_core.c:(.text+0x2200): undefined reference to `machine_kexec_cleanup'
mipsel-linux-ld: kernel/kexec_core.o: in function `__crash_kexec':
kernel/kexec_core.c:(.text+0x2480): undefined reference to `machine_crash_shutdown'
mipsel-linux-ld: kernel/kexec_core.c:(.text+0x2488): undefined reference to `machine_kexec'
mipsel-linux-ld: kernel/kexec_core.o: in function `kernel_kexec':
kernel/kexec_core.c:(.text+0x29b8): undefined reference to `machine_shutdown'
mipsel-linux-ld: kernel/kexec_core.c:(.text+0x29c0): undefined reference to `machine_kexec'
--------------------------------------------------------------------
Here, change the dependency of building kexec_core related object files,
and the ifdeffery in mips from CONFIG_KEXEC to CONFIG_KEXEC_CORE.
Link: https://lkml.kernel.org/r/20231208073036.7884-4-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/
202311302042.sn8cDPIX-lkp@intel.com/
Cc: Eric DeVolder <eric_devolder@yahoo.com>
Cc: Ignat Korchagin <ignat@cloudflare.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Baoquan He [Fri, 8 Dec 2023 07:30:33 +0000 (15:30 +0800)]
m68k, kexec: fix the incorrect ifdeffery and build dependency of CONFIG_KEXEC
The select of KEXEC for CRASH_DUMP in kernel/Kconfig.kexec will be
dropped, then compiling errors will be triggered if below config items are
set:
===
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_CRASH_DUMP=y
===
Here, change the dependency of buinding machine_kexec.o relocate_kernel.o
and the ifdeffery in asm/kexe.h to CONFIG_KEXEC_CORE.
Link: https://lkml.kernel.org/r/20231208073036.7884-3-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Cc: Eric DeVolder <eric_devolder@yahoo.com>
Cc: Ignat Korchagin <ignat@cloudflare.com>
Cc: kernel test robot <lkp@intel.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Baoquan He [Fri, 8 Dec 2023 07:30:32 +0000 (15:30 +0800)]
loongarch, kexec: change dependency of object files
Patch series "kexec: fix the incorrect ifdeffery and dependency of
CONFIG_KEXEC".
The select of KEXEC for CRASH_DUMP in kernel/Kconfig.kexec will be
dropped, then compiling errors will be triggered if below config items are
set:
===
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_CRASH_DUMP=y
===
E.g on mips, below link error are seen:
--------------------------------------------------------------------
mipsel-linux-ld: kernel/kexec_core.o: in function `kimage_free':
kernel/kexec_core.c:(.text+0x2200): undefined reference to `machine_kexec_cleanup'
mipsel-linux-ld: kernel/kexec_core.o: in function `__crash_kexec':
kernel/kexec_core.c:(.text+0x2480): undefined reference to `machine_crash_shutdown'
mipsel-linux-ld: kernel/kexec_core.c:(.text+0x2488): undefined reference to `machine_kexec'
mipsel-linux-ld: kernel/kexec_core.o: in function `kernel_kexec':
kernel/kexec_core.c:(.text+0x29b8): undefined reference to `machine_shutdown'
mipsel-linux-ld: kernel/kexec_core.c:(.text+0x29c0): undefined reference to `machine_kexec'
--------------------------------------------------------------------
Here, change the incorrect dependency of building kexec_core related
object files, and the ifdeffery on architectures from CONFIG_KEXEC to
CONFIG_KEXEC_CORE.
Testing:
========
Passed on mips and loognarch with the LKP reproducer.
This patch (of 5):
Currently, in arch/loongarch/kernel/Makefile, building machine_kexec.o
relocate_kernel.o depends on CONFIG_KEXEC.
Whereas, since we will drop the select of KEXEC for CRASH_DUMP in
kernel/Kconfig.kexec, compiling error will be triggered if below config
items are set:
===
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_CRASH_DUMP=y
===
---------------------------------------------------------------
loongarch64-linux-ld: kernel/kexec_core.o: in function `.L209':
>> kexec_core.c:(.text+0x1660): undefined reference to `machine_kexec_cleanup'
loongarch64-linux-ld: kernel/kexec_core.o: in function `.L287':
>> kexec_core.c:(.text+0x1c5c): undefined reference to `machine_crash_shutdown'
>> loongarch64-linux-ld: kexec_core.c:(.text+0x1c64): undefined reference to `machine_kexec'
loongarch64-linux-ld: kernel/kexec_core.o: in function `.L2^B5':
>> kexec_core.c:(.text+0x2090): undefined reference to `machine_shutdown'
loongarch64-linux-ld: kexec_core.c:(.text+0x20a0): undefined reference to `machine_kexec'
---------------------------------------------------------------
Here, change the dependency of machine_kexec.o relocate_kernel.o to
CONFIG_KEXEC_CORE can fix above building error.
Link: https://lkml.kernel.org/r/20231208073036.7884-1-bhe@redhat.com
Link: https://lkml.kernel.org/r/20231208073036.7884-2-bhe@redhat.com
Signed-off-by: Baoquan He <bhe@redhat.com>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/
202311300946.kHE9Iu71-lkp@intel.com/
Cc: Eric DeVolder <eric_devolder@yahoo.com>
Cc: Ignat Korchagin <ignat@cloudflare.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Fri, 8 Dec 2023 17:50:18 +0000 (17:50 +0000)]
mm/damon/core: make damon_start() waits until kdamond_fn() starts
The cleanup tasks of kdamond threads including reset of corresponding
DAMON context's ->kdamond field and decrease of global nr_running_ctxs
counter is supposed to be executed by kdamond_fn(). However, commit
0f91d13366a4 ("mm/damon: simplify stop mechanism") made neither
damon_start() nor damon_stop() ensure the corresponding kdamond has
started the execution of kdamond_fn().
As a result, the cleanup can be skipped if damon_stop() is called fast
enough after the previous damon_start(). Especially the skipped reset
of ->kdamond could cause a use-after-free.
Fix it by waiting for start of kdamond_fn() execution from
damon_start().
Link: https://lkml.kernel.org/r/20231208175018.63880-1-sj@kernel.org
Fixes:
0f91d13366a4 ("mm/damon: simplify stop mechanism")
Signed-off-by: SeongJae Park <sj@kernel.org>
Reported-by: Jakub Acs <acsjakub@amazon.de>
Cc: Changbin Du <changbin.du@intel.com>
Cc: Jakub Acs <acsjakub@amazon.de>
Cc: <stable@vger.kernel.org> # 5.15.x
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
David Hildenbrand [Wed, 6 Dec 2023 10:35:58 +0000 (11:35 +0100)]
selftests/mm: cow: print ksft header before printing anything else
Doing a ksft_print_msg() before the ksft_print_header() seems to confuse
the ksft framework in a strange way: running the test on the cmdline
results in the expected output.
But piping the output somewhere else, results in some odd output,
whereby we repeatedly get the same info printed:
# [INFO] detected THP size: 2048 KiB
# [INFO] detected hugetlb page size: 2048 KiB
# [INFO] detected hugetlb page size:
1048576 KiB
# [INFO] huge zeropage is enabled
TAP version 13
1..190
# [INFO] Anonymous memory tests in private mappings
# [RUN] Basic COW after fork() ... with base page
# [INFO] detected THP size: 2048 KiB
# [INFO] detected hugetlb page size: 2048 KiB
# [INFO] detected hugetlb page size:
1048576 KiB
# [INFO] huge zeropage is enabled
TAP version 13
1..190
# [INFO] Anonymous memory tests in private mappings
# [RUN] Basic COW after fork() ... with base page
ok 1 No leak from parent into child
# [RUN] Basic COW after fork() ... with swapped out base page
# [INFO] detected THP size: 2048 KiB
# [INFO] detected hugetlb page size: 2048 KiB
# [INFO] detected hugetlb page size:
1048576 KiB
# [INFO] huge zeropage is enabled
Doing the ksft_print_header() first seems to resolve that and gives us
the output we expect:
TAP version 13
# [INFO] detected THP size: 2048 KiB
# [INFO] detected hugetlb page size: 2048 KiB
# [INFO] detected hugetlb page size:
1048576 KiB
# [INFO] huge zeropage is enabled
1..190
# [INFO] Anonymous memory tests in private mappings
# [RUN] Basic COW after fork() ... with base page
ok 1 No leak from parent into child
# [RUN] Basic COW after fork() ... with swapped out base page
ok 2 No leak from parent into child
# [RUN] Basic COW after fork() ... with THP
ok 3 No leak from parent into child
# [RUN] Basic COW after fork() ... with swapped-out THP
ok 4 No leak from parent into child
# [RUN] Basic COW after fork() ... with PTE-mapped THP
ok 5 No leak from parent into child
Link: https://lkml.kernel.org/r/20231206103558.38040-1-david@redhat.com
Fixes:
f4b5fd6946e2 ("selftests/vm: anon_cow: THP tests")
Signed-off-by: David Hildenbrand <david@redhat.com>
Reported-by: Nico Pache <npache@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kefeng Wang [Thu, 7 Dec 2023 15:25:25 +0000 (23:25 +0800)]
mm: fix VMA heap bounds checking
After converting selinux to VMA heap check helper, the gcl triggers an
execheap SELinux denial, which is caused by a changed logic check.
Previously selinux only checked that the VMA range was within the VMA heap
range, and the implementation checks the intersection between the two
ranges, but the corner case (vm_end=start_brk, brk=vm_start) isn't handled
correctly.
Since commit
11250fd12eb8 ("mm: factor out VMA stack and heap checks") was
only a function extraction, it seems that the issue was introduced by
commit
0db0c01b53a1 ("procfs: fix /proc/<pid>/maps heap check"). Let's
fix above corner cases, meanwhile, correct the wrong indentation of the
stack and heap check helpers.
Fixes:
11250fd12eb8 ("mm: factor out VMA stack and heap checks")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reported-by: Ondrej Mosnacek <omosnace@redhat.com>
Closes: https://lore.kernel.org/selinux/CAFqZXNv0SVT0fkOK6neP9AXbj3nxJ61JAY4+zJzvxqJaeuhbFw@mail.gmail.com/
Tested-by: Ondrej Mosnacek <omosnace@redhat.com>
Link: https://lkml.kernel.org/r/20231207152525.2607420-1-wangkefeng.wang@huawei.com
Cc: David Hildenbrand <david@redhat.com>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Smalley <stephen.smalley.work@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Baoquan He [Tue, 5 Dec 2023 03:02:55 +0000 (11:02 +0800)]
riscv: fix VMALLOC_START definition
When below config items are set, compiler complained:
--------------------
CONFIG_CRASH_CORE=y
CONFIG_KEXEC_CORE=y
CONFIG_CRASH_DUMP=y
......
-----------------------
-------------------------------------------------------------------
arch/riscv/kernel/crash_core.c: In function 'arch_crash_save_vmcoreinfo':
arch/riscv/kernel/crash_core.c:11:58: warning: format '%lx' expects argument of type 'long unsigned int', but argument 2 has type 'int' [-Wformat=]
11 | vmcoreinfo_append_str("NUMBER(VMALLOC_START)=0x%lx\n", VMALLOC_START);
| ~~^
| |
| long unsigned int
| %x
----------------------------------------------------------------------
This is because on riscv macro VMALLOC_START has different type when
CONFIG_MMU is set or unset.
arch/riscv/include/asm/pgtable.h:
--------------------------------------------------
Changing it to _AC(0, UL) in case CONFIG_MMU=n can fix the warning.
Link: https://lkml.kernel.org/r/ZW7OsX4zQRA3mO4+@MiWiFi-R3L-srv
Signed-off-by: Baoquan He <bhe@redhat.com>
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org> # build-tested
Cc: Eric DeVolder <eric_devolder@yahoo.com>
Cc: Ignat Korchagin <ignat@cloudflare.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ignat Korchagin [Wed, 29 Nov 2023 22:04:09 +0000 (22:04 +0000)]
kexec: drop dependency on ARCH_SUPPORTS_KEXEC from CRASH_DUMP
In commit
f8ff23429c62 ("kernel/Kconfig.kexec: drop select of KEXEC for
CRASH_DUMP") we tried to fix a config regression, where CONFIG_CRASH_DUMP
required CONFIG_KEXEC.
However, it was not enough at least for arm64 platforms. While further
testing the patch with our arm64 config I noticed that CONFIG_CRASH_DUMP
is unavailable in menuconfig. This is because CONFIG_CRASH_DUMP still
depends on the new CONFIG_ARCH_SUPPORTS_KEXEC introduced in commit
91506f7e5d21 ("arm64/kexec: refactor for kernel/Kconfig.kexec") and on
arm64 CONFIG_ARCH_SUPPORTS_KEXEC requires CONFIG_PM_SLEEP_SMP=y, which in
turn requires either CONFIG_SUSPEND=y or CONFIG_HIBERNATION=y neither of
which are set in our config.
Given that we already established that CONFIG_KEXEC (which is a switch for
kexec system call itself) is not required for CONFIG_CRASH_DUMP drop
CONFIG_ARCH_SUPPORTS_KEXEC dependency as well. The arm64 kernel builds
just fine with CONFIG_CRASH_DUMP=y and with both CONFIG_KEXEC=n and
CONFIG_KEXEC_FILE=n after
f8ff23429c62 ("kernel/Kconfig.kexec: drop select
of KEXEC for CRASH_DUMP") and this patch are applied given that the
necessary shared bits are included via CONFIG_KEXEC_CORE dependency.
[bhe@redhat.com: don't export some symbols when CONFIG_MMU=n]
Link: https://lkml.kernel.org/r/ZW03ODUKGGhP1ZGU@MiWiFi-R3L-srv
[bhe@redhat.com: riscv, kexec: fix dependency of two items]
Link: https://lkml.kernel.org/r/ZW04G/SKnhbE5mnX@MiWiFi-R3L-srv
Link: https://lkml.kernel.org/r/20231129220409.55006-1-ignat@cloudflare.com
Fixes:
91506f7e5d21 ("arm64/kexec: refactor for kernel/Kconfig.kexec")
Signed-off-by: Ignat Korchagin <ignat@cloudflare.com>
Signed-off-by: Baoquan He <bhe@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: <stable@vger.kernel.org> # 6.6+: f8ff234: kernel/Kconfig.kexec: drop select of KEXEC for CRASH_DUMP
Cc: <stable@vger.kernel.org> # 6.6+
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Levi Yun [Thu, 9 Nov 2023 16:08:22 +0000 (16:08 +0000)]
maple_tree: change return type of mas_split_final_node as void.
mas_split_final_node() always returns true and its return value is never
checked.
Change return type to void.
Link: https://lkml.kernel.org/r/20231109160821.16248-2-ppbuk5246@gmail.com
Signed-off-by: Levi Yun <ppbuk5246@gmail.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Barry Song [Wed, 6 Dec 2023 11:00:54 +0000 (00:00 +1300)]
mm: compaction: avoid fast_isolate_freepages blindly choose improper pageblock
Testing shows fast_isolate_freepages can blindly choose an unsuitable
pageblock from time to time particularly while the min mark is used from
XXX path:
if (!page) {
cc->fast_search_fail++;
if (scan_start) {
/*
* Use the highest PFN found above min. If one was
* not found, be pessimistic for direct compaction
* and use the min mark.
*/
if (highest >= min_pfn) {
page = pfn_to_page(highest);
cc->free_pfn = highest;
} else {
if (cc->direct_compaction && pfn_valid(min_pfn)) { /* XXX */
page = pageblock_pfn_to_page(min_pfn,
min(pageblock_end_pfn(min_pfn),
zone_end_pfn(cc->zone)),
cc->zone);
cc->free_pfn = min_pfn;
}
}
}
}
The reason is that no code is doing any check on the min_pfn
min_pfn = pageblock_start_pfn(cc->free_pfn - (distance >> 1));
In contrast, slow path of isolate_freepages() is always skipping
unsuitable pageblocks in a decent way.
This issue doesn't happen quite often. When running 25 machines with
16GiB memory for one night, most of them can hit this unexpected code
path. However the frequency isn't like many times per second. It might
be one time in a couple of hours. Thus, it is very hard to measure the
visible performance impact in my machines though the affection of choosing
the unsuitable migration_target should be negative in theory.
I feel it's still worth fixing this to at least make the code
theoretically self-explanatory as it is quite odd an unsuitable
migration_target can be still migration_target.
Link: https://lkml.kernel.org/r/20231206110054.61617-1-v-songbaohua@oppo.com
Signed-off-by: Barry Song <v-songbaohua@oppo.com>
Reported-by: Zhanyuan Hu <huzhanyuan@oppo.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Chen Haonan [Wed, 6 Dec 2023 10:36:27 +0000 (18:36 +0800)]
mm: use vma_pages() for vma objects
vma_pages() is more readable and also better at avoiding error codes, so
use vma_pages() instead of direct operations on vma
Link: https://lkml.kernel.org/r/tencent_151850CF327EB055BBC83298A929BD06CD0A@qq.com
Signed-off-by: Chen Haonan <chen.haonan2@zte.com.cn>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Li zeming [Tue, 5 Dec 2023 02:17:51 +0000 (10:17 +0800)]
mm: cma: remove unnecessary initialization of ret
The ret variable can be defined without assigning a value, as it is
assigned before use.
Link: https://lkml.kernel.org/r/20231205021751.100459-1-zeming@nfschina.com
Signed-off-by: Li zeming <zeming@nfschina.com>
Reviewed-by: Andrew Morton <akpm@linux-foudation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Muchun Song [Tue, 5 Dec 2023 03:08:53 +0000 (11:08 +0800)]
mm: hugetlb_vmemmap: move mmap lock to vmemmap_remap_range()
All the users of vmemmap_remap_range() will hold the mmap lock and release
it once it returns, it is naturally to move the lock to
vmemmap_remap_range() to simplify the code and the users.
Link: https://lkml.kernel.org/r/20231205030853.3921-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Muchun Song [Tue, 5 Dec 2023 03:05:30 +0000 (11:05 +0800)]
mm: hugetlb_vmemmap: add check of CONFIG_MEMORY_HOTPLUG back
The compiler will optimize the code as much as possible if we add the
check of CONFIG_MEMORY_HOTPLUG back.
Link: https://lkml.kernel.org/r/20231205030530.3802-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Li zeming [Tue, 5 Dec 2023 02:29:54 +0000 (10:29 +0800)]
mm: filemap: remove unnecessary iitialization of ret
The ret variable can be defined without assigning a value, as it is
assigned before use.
Link: https://lkml.kernel.org/r/20231205022954.101045-1-zeming@nfschina.com
Signed-off-by: Li zeming <zeming@nfschina.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Dmytro Maluka [Tue, 5 Dec 2023 17:02:44 +0000 (18:02 +0100)]
mm/thp: add CONFIG_TRANSPARENT_HUGEPAGE_NEVER option
Currently enabling THP support (CONFIG_TRANSPARENT_HUGEPAGE) requires
enabling either CONFIG_TRANSPARENT_HUGEPAGE_ALWAYS or
CONFIG_TRANSPARENT_HUGEPAGE_MADVISE, which both cause khugepaged starting
by default at kernel bootup. Add the third choice
CONFIG_TRANSPARENT_HUGEPAGE_NEVER, in line with the existing kernel
command line setting transparent_hugepage=never, to disable THP by default
(in particular, to prevent starting khugepaged by default) but still allow
enabling it at runtime via sysfs.
Rationale: khugepaged has its own non-negligible memory cost even if it is
not used by any applications, since it bumps up vm.min_free_kbytes to its
own required minimum in set_recommended_min_free_kbytes(). For example,
on a machine with 4GB RAM, with 3 mm zones and pageblock_order ==
MAX_ORDER, starting khugepaged causes vm.min_free_kbytes increase from 8MB
to 132MB.
So if we use THP on machines with e.g. >=8GB of memory for better
performance, but avoid using it on lower-memory machines to avoid its
memory overhead, then for the same reason we also want to avoid even
starting khugepaged on those <8GB machines. So with
CONFIG_TRANSPARENT_HUGEPAGE_NEVER we can use the same kernel image on both
>=8GB and <8GB machines, with THP support enabled but khugepaged not
started by default. The userspace can then decide to enable THP via sysfs
if needed, based on the total amount of memory.
This could also be achieved with the existing transparent_hugepage=never
setting in the kernel command line instead. But it seems cleaner to avoid
tweaking the command line for such a basic setting.
P.S. I see that CONFIG_TRANSPARENT_HUGEPAGE_NEVER was already proposed
in the past [1] but without an explanation of the purpose.
[1] https://lore.kernel.org/all/
202211301651462590168@zte.com.cn/
Link: https://lkml.kernel.org/r/20231205170244.2746210-1-dmaluka@chromium.org
Link: https://lore.kernel.org/all/20231204163254.2636289-1-dmaluka@chromium.org/
Signed-off-by: Dmytro Maluka <dmaluka@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kefeng Wang [Fri, 10 Nov 2023 03:33:21 +0000 (11:33 +0800)]
mm: huge_memory: use more folio api in __split_huge_page_tail()
Use more folio APIs to save six compound_head() calls in
__split_huge_page_tail().
Link: https://lkml.kernel.org/r/20231110033324.2455523-5-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Catalin Marinas [Fri, 1 Dec 2023 19:08:29 +0000 (19:08 +0000)]
kmemleak: avoid RCU stalls when freeing metadata for per-CPU pointers
On systems with large number of CPUs, the following soft lockup splat
might sometimes happen:
[ 2656.001617] watchdog: BUG: soft lockup - CPU#364 stuck for 21s! [ksoftirqd/364:2206]
:
[ 2656.141194] RIP: 0010:_raw_spin_unlock_irqrestore+0x3d/0x70
:
2656.241214] Call Trace:
[ 2656.243971] <IRQ>
[ 2656.246237] ? show_trace_log_lvl+0x1c4/0x2df
[ 2656.251152] ? show_trace_log_lvl+0x1c4/0x2df
[ 2656.256066] ? kmemleak_free_percpu+0x11f/0x1f0
[ 2656.261173] ? watchdog_timer_fn+0x379/0x470
[ 2656.265984] ? __pfx_watchdog_timer_fn+0x10/0x10
[ 2656.271179] ? __hrtimer_run_queues+0x5f3/0xd00
[ 2656.276283] ? __pfx___hrtimer_run_queues+0x10/0x10
[ 2656.281783] ? ktime_get_update_offsets_now+0x95/0x2c0
[ 2656.287573] ? ktime_get_update_offsets_now+0xdd/0x2c0
[ 2656.293380] ? hrtimer_interrupt+0x2e9/0x780
[ 2656.298221] ? __sysvec_apic_timer_interrupt+0x184/0x640
[ 2656.304211] ? sysvec_apic_timer_interrupt+0x8e/0xc0
[ 2656.309807] </IRQ>
[ 2656.312169] <TASK>
[ 2656.326110] kmemleak_free_percpu+0x11f/0x1f0
[ 2656.331015] free_percpu.part.0+0x1b/0xe70
[ 2656.335635] free_vfsmnt+0xb9/0x100
[ 2656.339567] rcu_do_batch+0x3c8/0xe30
[ 2656.363693] rcu_core+0x3de/0x5a0
[ 2656.367433] __do_softirq+0x2d0/0x9a8
[ 2656.381119] run_ksoftirqd+0x36/0x60
[ 2656.385145] smpboot_thread_fn+0x556/0x910
[ 2656.394971] kthread+0x2a4/0x350
[ 2656.402826] ret_from_fork+0x29/0x50
[ 2656.406861] </TASK>
The issue is caused by kmemleak registering each per_cpu_ptr()
corresponding to the __percpu pointer. This is unnecessary since such
individual per-CPU pointers are not tracked anyway. Create a new
object_percpu_tree_root rbtree that stores a single __percpu pointer
together with an OBJECT_PERCPU flag for the kmemleak metadata. Scanning
needs to be done for all per_cpu_ptr() pointers with a cond_resched()
between each CPU iteration to avoid RCU stalls.
[catalin.marinas@arm.com: update comment]
Link: https://lkml.kernel.org/r/20231206114414.2085824-1-catalin.marinas@arm.com
Link: https://lore.kernel.org/r/20231127194153.289626-1-longman@redhat.comLink:
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Waiman Long <longman@redhat.com>
Closes: https://lore.kernel.org/r/
20231127194153.289626-1-longman@redhat.com
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Steven Rostedt (Google) [Fri, 1 Dec 2023 19:59:36 +0000 (14:59 -0500)]
mm/rmap: fix misplaced parenthesis of a likely()
Running my yearly branch profiler to see where likely/unlikely annotation
may be added or removed, I discovered this:
correct incorrect % Function File Line
------- --------- - -------- ---- ----
0 457918 100 page_try_dup_anon_rmap rmap.h 264
[..]
458021 0 0 page_try_dup_anon_rmap rmap.h 265
I thought it was interesting that line 264 of rmap.h had a 100% incorrect
annotation, but the line directly below it was 100% correct. Looking at the
code:
if (likely(!is_device_private_page(page) &&
unlikely(page_needs_cow_for_dma(vma, page))))
It didn't make sense. The "likely()" was around the entire if statement
(not just the "!is_device_private_page(page)"), which also included the
"unlikely()" portion of that if condition.
If the unlikely portion is unlikely to be true, that would make the entire
if condition unlikely to be true, so it made no sense at all to say the
entire if condition is true.
What is more likely to be likely is just the first part of the if statement
before the && operation. It's likely to be a misplaced parenthesis. And
after making the if condition broken into a likely() && unlikely(), both
now appear to be correct!
Link: https://lkml.kernel.org/r/20231201145936.5ddfdb50@gandalf.local.home
Fixes:
fb3d824d1a46c ("mm/rmap: split page_dup_rmap() into page_dup_file_rmap() and page_try_dup_anon_rmap()")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Hildenbrand <david@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Ryan Roberts [Fri, 1 Dec 2023 16:10:45 +0000 (16:10 +0000)]
mm/readahead: do not allow order-1 folio
The THP machinery does not support order-1 folios because it requires meta
data spanning the first 3 `struct page`s. So order-2 is the smallest
large folio that we can safely create.
There was a theoretical bug whereby if ra->size was 2 or 3 pages (due to
the device-specific bdi->ra_pages being set that way), we could end up
with order = 1. Fix this by unconditionally checking if the preferred
order is 1 and if so, set it to 0. Previously this was done in a few
specific places, but with this refactoring it is done just once,
unconditionally, at the end of the calculation.
This is a theoretical bug found during review of the code; I have no
evidence to suggest this manifests in the real world (I expect all
device-specific ra_pages values are much bigger than 3).
Link: https://lkml.kernel.org/r/20231201161045.3962614-1-ryan.roberts@arm.com
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kefeng Wang [Sat, 18 Nov 2023 02:32:32 +0000 (10:32 +0800)]
mm: memory: use folio_prealloc() in wp_page_copy()
Use folio_prealloc() helper to simplify code a bit.
Link: https://lkml.kernel.org/r/20231118023232.1409103-6-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kefeng Wang [Sat, 18 Nov 2023 02:32:31 +0000 (10:32 +0800)]
mm: memory: use a folio in do_cow_fault()
Use folio_prealloc() helper and convert to use a folio in do_cow_fault(),
which save five compound_head() calls.
Link: https://lkml.kernel.org/r/20231118023232.1409103-5-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kefeng Wang [Sat, 18 Nov 2023 02:32:30 +0000 (10:32 +0800)]
mm: memory: rename page_copy_prealloc() to folio_prealloc()
Let's rename page_copy_prealloc() to folio_prealloc(), which could be
reused in more functons, as it maybe zero the new page, pass a new
need_zero to it, and call the vma_alloc_zeroed_movable_folio() if
need_zero is true.
Link: https://lkml.kernel.org/r/20231118023232.1409103-4-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kefeng Wang [Sat, 18 Nov 2023 02:32:29 +0000 (10:32 +0800)]
mm: memory: use a folio in validate_page_before_insert()
Use a folio in validate_page_before_insert() to save two compound_head()
calls.
Link: https://lkml.kernel.org/r/20231118023232.1409103-3-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reviewed-by: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Kefeng Wang [Sat, 18 Nov 2023 02:32:28 +0000 (10:32 +0800)]
mm: ksm: use more folio api in ksm_might_need_to_copy()
Patch series "mm: cleanup and use more folio in page fault", v3.
Rename page_copy_prealloc() to folio_prealloc(), which is used by more
functions, also do more folio conversion in page fault.
This patch (of 5):
Since ksm only support normal page, no swapout/in for ksm large folio too,
add large folio check in ksm_might_need_to_copy(), also convert
page->index to folio->index as page->index is going away.
Then convert ksm_might_need_to_copy() to use more folio api to save nine
compound_head() calls, short 'address' to reduce max-line-length.
Link: https://lkml.kernel.org/r/20231118023232.1409103-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20231118023232.1409103-2-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Thu, 30 Nov 2023 02:36:52 +0000 (02:36 +0000)]
Docs/admin-guide/mm/damon/usage: document for quota goals
Update DAMON sysfs usage for newly added DAMOS quota goals interface.
Link: https://lkml.kernel.org/r/20231130023652.50284-10-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Thu, 30 Nov 2023 02:36:51 +0000 (02:36 +0000)]
Docs/ABI/damon: document DAMOS quota goals
Update DAMON ABI document for the newly added DAMON sysfs files and inputs
for DAMOS quota goals.
Link: https://lkml.kernel.org/r/20231130023652.50284-9-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Thu, 30 Nov 2023 02:36:50 +0000 (02:36 +0000)]
Docs/mm/damon/design: document DAMOS quota auto tuning
Document the DAMOS quota auto tuning feature on the design document.
Link: https://lkml.kernel.org/r/20231130023652.50284-8-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Thu, 30 Nov 2023 02:36:49 +0000 (02:36 +0000)]
selftests/damon: test quota goals directory
Add DAMON selftests for testing creation/existence of quota goals
directories and files, and simple valid input writes.
Link: https://lkml.kernel.org/r/20231130023652.50284-7-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Thu, 30 Nov 2023 02:36:48 +0000 (02:36 +0000)]
mm/damon/core-test: add a unit test for the feedback loop algorithm
Implement a simple kunit test for testing the behavior of the feedback
loop algorithm for the aim-oriented feedback-friven DAMOS aggressiveness
auto tuning.
Link: https://lkml.kernel.org/r/20231130023652.50284-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Thu, 30 Nov 2023 02:36:47 +0000 (02:36 +0000)]
mm/damon/sysfs-schemes: implement a command for scheme quota goals only commit
To update DAMOS quota goals, users need to enter 'commit' command to the
'state' file of the kdamond, which applies not only the goals but entire
inputs. It is inefficient. Implement yet another 'state' file input
command for reading and committing only the scheme quota goals, namely
'commit_schemes_quota_goals'.
Link: https://lkml.kernel.org/r/20231130023652.50284-5-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Thu, 30 Nov 2023 02:36:46 +0000 (02:36 +0000)]
mm/damon/sysfs-schemes: commit damos quota goals user input to DAMOS
Make DAMON sysfs interface to read the user inputs for DAMOS quota goals
and pass those to DAMOS, so that the users can use the quota auto-tuning
feature. It uses the DAMON sysfs interface's user input commit mechanism,
which applies all user inputs for initial starting of DAMON and online
input updates, which can be done by writing 'on' and 'commit' to the
kdamond's 'state' file, respectively. In other words, the user should
periodically write appropriate value to 'current_value' files and 'commit'
command to the 'state' file. 'target_value' files could also be similarly
updated at any time.
Note that the interface is supporting multiple goals while the core logic
supports only one goal. DAMON sysfs interface passes only best feedback
among the given inputs, to avoid making DAMOS too aggressive.
Link: https://lkml.kernel.org/r/20231130023652.50284-4-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Thu, 30 Nov 2023 02:36:45 +0000 (02:36 +0000)]
mm/damon/sysfs-schemes: implement files for scheme quota goals setup
Implement DAMON sysfs directories and files for the goals of DAMOS quota.
Those allow users set multiple goals for their aim, with target values.
Users can further enter the current score value for each goal as feedback
for DAMOS.
Note that this commit is implementing only the basic file operations, and
not connecting the files with the DAMOS core logic. Hence writing
something to the files makes no real effect. The following commit will
connect the file operations and the core logic.
Link: https://lkml.kernel.org/r/20231130023652.50284-3-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
SeongJae Park [Thu, 30 Nov 2023 02:36:44 +0000 (02:36 +0000)]
mm/damon/core: implement goal-oriented feedback-driven quota auto-tuning
Patch series "mm/damon: let users feed and tame/auto-tune DAMOS".
Introduce Aim-oriented Feedback-driven DAMOS Aggressiveness Auto-tuning.
It makes DAMOS self-tuned with periodic simple user feedback.
Background: DAMOS Control Difficulty
====================================
DAMOS helps users easily implement access pattern aware system operations.
However, controlling DAMOS in the wild is not that easy.
The basic way for DAMOS control is specifying the target access pattern.
In this approach, the user is assumed to well understand the access
pattern and the characteristics of the system and the workloads. Though
there are useful tools for that, it takes time and effort depending on the
complexity and the dynamicity of the system and the workloads. After all,
the access pattern consists of three ranges, namely the size, the access
rate, and the age of the regions. It means users need to tune six
parameters, which is anyway not a simple task.
One of the worst cases would be DAMOS being too aggressive like a
berserker, and therefore consuming too much system resource and making
unwanted radical system operations. To let users avoid such cases, DAMOS
allows users to set the upper-limit of the schemes' aggressiveness, namely
DAMOS quota. DAMOS further provides its best-effort under the limit by
prioritizing regions based on the access pattern of the regions. For
example, users can ask DAMOS to page out up to 100 MiB of memory regions
per second. Then DAMOS pages out regions that are not accessed for a
longer time (colder) first under the limit. This allows users to set the
target access pattern a bit naive with wider ranges, and focus on tuning
only one parameter, the quota. In other words, the number of parameters
to tune can be reduced from six to one.
Still, however, the optimum value for the quota depends on the system and
the workloads' characteristics, so not that simple. The number of
parameters to tune can also increase again if the user needs to run
multiple schemes.
Aim-oriented Feedback-driven DAMOS Aggressiveness Auto Tuning
=============================================================
Users would use DAMOS since they want to achieve something with it. They
will likely have measurable metrics representing the achievement and the
target number of the metric like SLO, and continuously measure that
anyway. While the additional cost of getting the information is nearly
zero, it could be useful for DAMOS to understand how appropriate its
current aggressiveness is set, and adjust it on its own to make the metric
value more close to the target.
Based on this idea, we introduce a new way of tuning DAMOS with nearly
zero additional effort, namely Aim-oriented Feedback-driven DAMOS
Aggressiveness Auto Tuning. It asks users to provide feedback
representing how well DAMOS is doing relative to the users' aim. Then
DAMOS adjusts its aggressiveness, specifically the quota that provides
the best effort result under the limit, based on the current level of
the aggressiveness and the users' feedback.
Implementation
==============
The implementation asks users to represent the feedback with score
numbers. The scores could be anything including user-space specific
metrics including latency and throughput of special user-space workloads,
and system metrics including free memory ratio, memory pressure stall time
(PSI), and active to inactive LRU lists size ratio. The feedback scores
and the aggressiveness of the given DAMOS scheme are assumed to be
positively proportional, though. Selecting metrics of the assumption is
the users' responsibility.
The core logic uses the below simple feedback loop algorithm to calculate
the next aggressiveness level of the scheme from the current
aggressiveness level and the current feedback (target_score and
current_score). It calculates the compensation for next aggressiveness as
a proportion of current aggressiveness and distance to the target score.
As a result, it arrives at the near-goal state in a short time using big
steps when it's far from the goal, but avoids making unnecessarily radical
changes that could turn out to be a bad decision using small steps when
its near to the goal.
f(n) = max(1, f(n - 1) * ((target_score - current_score) / target_score + 1))
Note that the compensation value becomes negative when it's over
achieving the goal. That's why the feedback metric and the
aggressiveness of the scheme should be positively proportional. The
distance-adaptive speed manipulation is simply applied.
Example Use Cases
=================
If users want to reduce the memory footprint of the system as much as
possible as long as the time spent for handling the resulting memory
pressure is within a threshold, they could use DAMOS scheme that reclaims
cold memory regions aiming for a little level of memory pressure stall
time.
If users want the active/inactive LRU lists well balanced to reduce the
performance impact due to possible future memory pressure, they could use
two schemes. The first one would be set to locate hot pages in the active
LRU list, aiming for a specific active-to-inactive LRU list size ratio,
say, 70%. The second one would be to locate cold pages in the inactive
LRU list, aiming for a specific inactive-to-active LRU list size ratio,
say, 30%. Then, DAMOS will balance the two schemes based on the goal and
feedback.
This aim-oriented auto tuning could also be useful for general
balancing-required access aware system operations such as system memory
auto scaling[3] and tiered memory management[4]. These two example usages
are not what current DAMOS implementation is already supporting, but
require additional DAMOS action developments, though.
Evaluation: subtle memory pressure aiming proactive reclamation
===============================================================
To show if the implementation works as expected, we prepare four different
system configurations on AWS i3.metal instances. The first setup
(original) runs the workload without any DAMOS scheme. The second setup
(not-tuned) runs the workload with a virtual address space-based proactive
reclamation scheme that pages out memory regions that are not accessed for
five seconds or more. The third setup (offline-tuned) runs the same
proactive reclamation DAMOS scheme, but after making it tuned for each
workload offline, using our previous user-space driven automatic tuning
approach, namely DAMOOS[1]. The fourth and final setup (AFDAA) runs the
scheme that is the same as that of 'not-tuned' setup, but aims to keep
0.5% of 'some' memory pressure stall time (PSI) for the last 10 seconds
using the aiming-oriented auto tuning.
For each setup, we run realistic workloads from PARSEC3 and SPLASH-2X
benchmark suites. For each run, we measure RSS and runtime of the
workload, and 'some' memory pressure stall time (PSI) of the system. We
repeat the runs five times and use averaged measurements.
For simple comparison of the results, we normalize the measurements to
those of 'original'. In the case of the PSI, though, the measurement for
'original' was zero, so we normalize the value to that of 'not-tuned'
scheme's result. The normalized results are shown below.
Not-tuned Offline-tuned AFDAA
RSS 0.
622688178226118 0.
787950678944904 0.
740093483278979
runtime 1.
11767826657912 1.
0564674983585 1.
0910833880499
PSI 1 0.
727521443794069 0.
308498846350299
The 'not-tuned' scheme achieves about 38.7% memory saving but incur about
11.7% runtime slowdown. The 'offline-tuned' scheme achieves about 22.2%
memory saving with about 5.5% runtime slowdown. It also achieves about
28.2% memory pressure stall time saving. AFDAA achieves about 26% memory
saving with about 9.1% runtime slowdown. It also achieves about 69.1%
memory pressure stall time saving. We repeat this test multiple times,
and get consistent results. AFDAA is now integrated in our daily DAMON
performance test setup.
Apparently the aggressiveness of 'AFDAA' setup is somewhere between those
of 'not-tuned' and 'offline-tuned' setup, since its memory saving and
runtime overhead are between those of the other two setups. Actually we
set the memory pressure stall time goal aiming for this middle
aggressiveness. The difference in the two metrics are not significant,
though. However, it shows significant saving of the memory pressure stall
time, which was the goal of the auto-tuning, over the two variants.
Hence, we conclude the automatic tuning is working as expected.
Please note that the AFDAA setup is only for the evaluation, and
therefore intentionally set a bit aggressive. It might not be
appropriate for production environments.
The test code is also available[2], so you could reproduce it on your
system and workloads.
Patches Sequence
================
The first four patches implement the core logic and user interfaces for
the auto tuning. The first patch implements the core logic for the auto
tuning, and the API for DAMOS users in the kernel space. The second
patch implements basic file operations of DAMON sysfs directories and
files that will be used for setting the goals and providing the
feedback. The third patch connects the quota goals files inputs to the
DAMOS core logic. Finally the fourth patch implements a dedicated DAMOS
sysfs command for efficiently committing the quota goals feedback.
Two patches for simple tests of the logic and interfaces follow. The
fifth patch implements the core logic unit test. The sixth patch
implements a selftest for the DAMON Sysfs interface for the goals.
Finally, three patches for documentation follows. The seventh patch
documents the design of the feature. The eighth patch updates the API
doc for the new sysfs files. The final eighth patch updates the usage
document for the features.
References
==========
[1] DAOS paper:
https://www.amazon.science/publications/daos-data-access-aware-operating-system
[2] Evaluation code:
https://github.com/damonitor/damon-tests/commit/
3f884e61193f0166b8724554b6d06b0c449a712d
[3] Memory auto scaling RFC idea:
https://lore.kernel.org/damon/
20231112195114.61474-1-sj@kernel.org/
[4] DAMON-based tiered memory management RFC idea:
https://lore.kernel.org/damon/
20231112195602.61525-1-sj@kernel.org/
This patch (of 9)
Users can effectively control the upper-limit aggressiveness of DAMOS
schemes using the quota feature. The quota provides best result under the
limit by prioritizing regions based on the access pattern. That said,
finding the best value, which could depend on dynamic characteristics of
the system and the workloads, is still challenging.
Implement a simple feedback-driven tuning mechanism and use it for
automatic tuning of DAMOS quota. The implementation allows users to
provide the feedback by setting a feedback score returning callback
function. Then DAMOS periodically calls the function back and adjusts the
quota based on the return value of the callback and current quota value.
Note that the absolute-value based time/size quotas still work as the
maximum hard limits of the scheme's aggressiveness. The feedback-driven
auto-tuned quota is applied only if it is not exceeding the manually set
maximum limits. Same for the scheme-target access pattern and filters
like other features.
[sj@kernel.org: document get_score_arg field of struct damos_quota]
Link: https://lkml.kernel.org/r/20231204170106.60992-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20231130023652.50284-1-sj@kernel.org
Link: https://lkml.kernel.org/r/20231130023652.50284-2-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: David Gow <davidgow@google.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Nico Pache [Wed, 29 Nov 2023 22:11:40 +0000 (15:11 -0700)]
selftests/mm: dont run ksm_functional_tests twice
ksm functional test is already being run. Remove the duplicate call to
./ksm_functional_tests.
Link: https://lkml.kernel.org/r/20231129221140.614713-1-npache@redhat.com
Fixes:
93fb70aa5904 ("selftests/vm: add KSM unmerge tests")
Signed-off-by: Nico Pache <npache@redhat.com>
Acked-by: Joel Savitz <jsavitz@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Nhat Pham [Thu, 30 Nov 2023 19:40:23 +0000 (11:40 -0800)]
zswap: shrink zswap pool based on memory pressure
Currently, we only shrink the zswap pool when the user-defined limit is
hit. This means that if we set the limit too high, cold data that are
unlikely to be used again will reside in the pool, wasting precious
memory. It is hard to predict how much zswap space will be needed ahead
of time, as this depends on the workload (specifically, on factors such as
memory access patterns and compressibility of the memory pages).
This patch implements a memcg- and NUMA-aware shrinker for zswap, that is
initiated when there is memory pressure. The shrinker does not have any
parameter that must be tuned by the user, and can be opted in or out on a
per-memcg basis.
Furthermore, to make it more robust for many workloads and prevent
overshrinking (i.e evicting warm pages that might be refaulted into
memory), we build in the following heuristics:
* Estimate the number of warm pages residing in zswap, and attempt to
protect this region of the zswap LRU.
* Scale the number of freeable objects by an estimate of the memory
saving factor. The better zswap compresses the data, the fewer pages
we will evict to swap (as we will otherwise incur IO for relatively
small memory saving).
* During reclaim, if the shrinker encounters a page that is also being
brought into memory, the shrinker will cautiously terminate its
shrinking action, as this is a sign that it is touching the warmer
region of the zswap LRU.
As a proof of concept, we ran the following synthetic benchmark: build the
linux kernel in a memory-limited cgroup, and allocate some cold data in
tmpfs to see if the shrinker could write them out and improved the overall
performance. Depending on the amount of cold data generated, we observe
from 14% to 35% reduction in kernel CPU time used in the kernel builds.
[nphamcs@gmail.com: check shrinker enablement early, use less costly stat flushing]
Link: https://lkml.kernel.org/r/20231206194456.3234203-1-nphamcs@gmail.com
Link: https://lkml.kernel.org/r/20231130194023.4102148-7-nphamcs@gmail.com
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Cc: Chengming Zhou <chengming.zhou@linux.dev>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Domenico Cerasuolo [Thu, 30 Nov 2023 19:40:22 +0000 (11:40 -0800)]
selftests: cgroup: update per-memcg zswap writeback selftest
The memcg-zswap self test is updated to adjust to the behavior change
implemented by commit
87730b165089 ("zswap: make shrinking memcg-aware"),
where zswap performs writeback for specific memcg.
Link: https://lkml.kernel.org/r/20231130194023.4102148-6-nphamcs@gmail.com
Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Tested-by: Bagas Sanjaya <bagasdotme@gmail.com>
Acked-by: Chris Li <chrisl@kernel.org> (Google)
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Domenico Cerasuolo [Thu, 30 Nov 2023 19:40:21 +0000 (11:40 -0800)]
mm: memcg: add per-memcg zswap writeback stat
Since zswap now writes back pages from memcg-specific LRUs, we now need a
new stat to show writebacks count for each memcg.
[nphamcs@gmail.com: rename ZSWP_WB to ZSWPWB]
Link: https://lkml.kernel.org/r/20231205193307.2432803-1-nphamcs@gmail.com
Link: https://lkml.kernel.org/r/20231130194023.4102148-5-nphamcs@gmail.com
Suggested-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Tested-by: Bagas Sanjaya <bagasdotme@gmail.com>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Domenico Cerasuolo [Thu, 30 Nov 2023 19:40:20 +0000 (11:40 -0800)]
zswap: make shrinking memcg-aware
Currently, we only have a single global LRU for zswap. This makes it
impossible to perform worload-specific shrinking - an memcg cannot
determine which pages in the pool it owns, and often ends up writing pages
from other memcgs. This issue has been previously observed in practice
and mitigated by simply disabling memcg-initiated shrinking:
https://lore.kernel.org/all/
20230530232435.
3097106-1-nphamcs@gmail.com/T/#u
This patch fully resolves the issue by replacing the global zswap LRU
with memcg- and NUMA-specific LRUs, and modify the reclaim logic:
a) When a store attempt hits an memcg limit, it now triggers a
synchronous reclaim attempt that, if successful, allows the new
hotter page to be accepted by zswap.
b) If the store attempt instead hits the global zswap limit, it will
trigger an asynchronous reclaim attempt, in which an memcg is
selected for reclaim in a round-robin-like fashion.
[nphamcs@gmail.com: use correct function for the onlineness check, use mem_cgroup_iter_break()]
Link: https://lkml.kernel.org/r/20231205195419.2563217-1-nphamcs@gmail.com
[nphamcs@gmail.com: drop the pool's reference at the end of the writeback step]
Link: https://lkml.kernel.org/r/20231206030627.4155634-1-nphamcs@gmail.com
Link: https://lkml.kernel.org/r/20231130194023.4102148-4-nphamcs@gmail.com
Signed-off-by: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Co-developed-by: Nhat Pham <nphamcs@gmail.com>
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Tested-by: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Nhat Pham [Thu, 30 Nov 2023 19:40:19 +0000 (11:40 -0800)]
memcontrol: implement mem_cgroup_tryget_online()
This patch implements a helper function that try to get a reference to an
memcg's css, as well as checking if it is online. This new function is
almost exactly the same as the existing mem_cgroup_tryget(), except for
the onlineness check. In the !CONFIG_MEMCG case, it always returns true,
analogous to mem_cgroup_tryget(). This is useful for e.g to the new zswap
writeback scheme, where we need to select the next online memcg as a
candidate for the global limit reclaim.
Link: https://lkml.kernel.org/r/20231130194023.4102148-3-nphamcs@gmail.com
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Tested-by: Bagas Sanjaya <bagasdotme@gmail.com>
Reviewed-by: Yosry Ahmed <yosryahmed@google.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Nhat Pham [Thu, 30 Nov 2023 19:40:18 +0000 (11:40 -0800)]
list_lru: allow explicit memcg and NUMA node selection
Patch series "workload-specific and memory pressure-driven zswap
writeback", v8.
There are currently several issues with zswap writeback:
1. There is only a single global LRU for zswap, making it impossible to
perform worload-specific shrinking - an memcg under memory pressure
cannot determine which pages in the pool it owns, and often ends up
writing pages from other memcgs. This issue has been previously
observed in practice and mitigated by simply disabling
memcg-initiated shrinking:
https://lore.kernel.org/all/
20230530232435.
3097106-1-nphamcs@gmail.com/T/#u
But this solution leaves a lot to be desired, as we still do not
have an avenue for an memcg to free up its own memory locked up in
the zswap pool.
2. We only shrink the zswap pool when the user-defined limit is hit.
This means that if we set the limit too high, cold data that are
unlikely to be used again will reside in the pool, wasting precious
memory. It is hard to predict how much zswap space will be needed
ahead of time, as this depends on the workload (specifically, on
factors such as memory access patterns and compressibility of the
memory pages).
This patch series solves these issues by separating the global zswap LRU
into per-memcg and per-NUMA LRUs, and performs workload-specific (i.e
memcg- and NUMA-aware) zswap writeback under memory pressure. The new
shrinker does not have any parameter that must be tuned by the user, and
can be opted in or out on a per-memcg basis.
As a proof of concept, we ran the following synthetic benchmark: build the
linux kernel in a memory-limited cgroup, and allocate some cold data in
tmpfs to see if the shrinker could write them out and improved the overall
performance. Depending on the amount of cold data generated, we observe
from 14% to 35% reduction in kernel CPU time used in the kernel builds.
This patch (of 6):
The interface of list_lru is based on the assumption that the list node
and the data it represents belong to the same allocated on the correct
node/memcg. While this assumption is valid for existing slab objects LRU
such as dentries and inodes, it is undocumented, and rather inflexible for
certain potential list_lru users (such as the upcoming zswap shrinker and
the THP shrinker). It has caused us a lot of issues during our
development.
This patch changes list_lru interface so that the caller must explicitly
specify numa node and memcg when adding and removing objects. The old
list_lru_add() and list_lru_del() are renamed to list_lru_add_obj() and
list_lru_del_obj(), respectively.
It also extends the list_lru API with a new function, list_lru_putback,
which undoes a previous list_lru_isolate call. Unlike list_lru_add, it
does not increment the LRU node count (as list_lru_isolate does not
decrement the node count). list_lru_putback also allows for explicit
memcg and NUMA node selection.
Link: https://lkml.kernel.org/r/20231130194023.4102148-1-nphamcs@gmail.com
Link: https://lkml.kernel.org/r/20231130194023.4102148-2-nphamcs@gmail.com
Signed-off-by: Nhat Pham <nphamcs@gmail.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Tested-by: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Domenico Cerasuolo <cerasuolodomenico@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vitaly Wool <vitaly.wool@konsulko.com>
Cc: Yosry Ahmed <yosryahmed@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Peng Zhang [Mon, 20 Nov 2023 07:09:37 +0000 (15:09 +0800)]
maple_tree: simplify mas_leaf_set_meta()
Now it seems that the incoming 'end' is already pointing to the last item,
so we can simplify this function, considering only whether the last slot
is being used. This has passed the maple tree test suite.
Link: https://lkml.kernel.org/r/20231120070937.35481-6-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Peng Zhang [Mon, 20 Nov 2023 07:09:36 +0000 (15:09 +0800)]
maple_tree: delete one of the two identical checks
There are two identical checks, delete one of them.
Link: https://lkml.kernel.org/r/20231120070937.35481-5-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Peng Zhang [Mon, 20 Nov 2023 07:09:35 +0000 (15:09 +0800)]
maple_tree: remove an unused parameter for ma_meta_end()
The parameter maple_type is not used, so remove it.
Link: https://lkml.kernel.org/r/20231120070937.35481-4-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Peng Zhang [Mon, 20 Nov 2023 07:09:34 +0000 (15:09 +0800)]
maple_tree: avoid ascending when mas->min is also the parent's minimum
When the child node is the first child of its parent node, mas->min does
not need to be updated. This can reduce the number of ascending times
in some cases.
Link: https://lkml.kernel.org/r/20231120070937.35481-3-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Peng Zhang [Mon, 20 Nov 2023 07:09:33 +0000 (15:09 +0800)]
maple_tree: move the check forward to avoid static check warning
Patch series "Some cleanups of maple tree", v2.
These are some small cleanups of maple tree.
This patch (of 5):
Put the check for gap before its reference to avoid Smatch static check
warnings. This is not a bug, it's just a validation program. Even with
this change, Smatch may still generate warnings because MT_BUG_ON()
doesn't necessarily stop the program. It may require fixing Smatch itself
to avoid these warnings.
Link: https://lkml.kernel.org/r/20231120070937.35481-1-zhangpeng.00@bytedance.com
Link: https://lkml.kernel.org/r/20231120070937.35481-2-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: http://lists.infradead.org/pipermail/maple-tree/2023-November/003046.html
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jiapeng Chong [Fri, 27 Oct 2023 08:49:44 +0000 (16:49 +0800)]
maple_tree: remove unused function
The function are defined in the maple_tree.c file, but not called
elsewhere, so delete the unused function.
lib/maple_tree.c:689:29: warning: unused function 'mas_pivot'.
Link: https://lkml.kernel.org/r/20231027084944.24888-1-jiapeng.chong@linux.alibaba.com
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7064
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Wed, 1 Nov 2023 17:16:29 +0000 (13:16 -0400)]
maple_tree: mtree_range_walk() clean up
mtree_range_walk() needed to be updated to avoid checking if there was a
pivot value. On closer examination, the code could avoid setting min or
max in certain scenarios. The commit removes the extra check for
pivot[offset] before setting max and only sets max when necessary. It
also only sets min if it is necessary by checking offset 0 prior to the
loop (as it has always done).
The commit also drops a dead node check since the end of the node will
return the array size when the last slot is occupied (by a potential reuse
in a dead node). The data will be discarded later if the node is marked
dead.
Benchmarking these changes results in an increase in performance of 5.45%
using the BENCH_WALK in the maple tree test code.
Link: https://lkml.kernel.org/r/20231101171629.3612299-13-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Wed, 1 Nov 2023 17:16:28 +0000 (13:16 -0400)]
maple_tree: don't find node end in mtree_lookup_walk()
Since the pivot being set is now reliable, the optimized loop no longer
needs to find the node end. The redundant check for a dead node can also
be avoided as there is no danger of using the wrong pivot since the
results will be thrown out in the case of a dead node by the later check.
This patch also adds a benchmark test for the function to the maple tree
test framework. The benchmark shows an average increase performance of
5.98% over 3 runs with this commit.
Link: https://lkml.kernel.org/r/20231101171629.3612299-12-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Wed, 1 Nov 2023 17:16:27 +0000 (13:16 -0400)]
maple_tree: use maple state end for write operations
ma_wr_state was previously tracking the end of the node for writing.
Since the implementation of the ma_state end tracking, this is duplicated
work. This patch removes the maple write state tracking of the end of the
node and uses the maple state end instead.
Link: https://lkml.kernel.org/r/20231101171629.3612299-11-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Wed, 1 Nov 2023 17:16:26 +0000 (13:16 -0400)]
maple_tree: remove mas_searchable()
Now that the status of the maple state is outside of the node, the
mas_searchable() function can be dropped for easier open-coding of what is
going on.
Link: https://lkml.kernel.org/r/20231101171629.3612299-10-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Wed, 1 Nov 2023 17:16:25 +0000 (13:16 -0400)]
maple_tree: separate ma_state node from status
The maple tree node is overloaded to keep status as well as the active
node. This, unfortunately, results in a re-walk on underflow or overflow.
Since the maple state has room, the status can be placed in its own enum
in the structure. Once an underflow/overflow is detected, certain modes
can restore the status to active and others may need to re-walk just that
one node to see the entry.
The status being an enum has the benefit of detecting unhandled status in
switch statements.
[Liam.Howlett@oracle.com: fix comments about MAS_*]
Link: https://lkml.kernel.org/r/20231106154124.614247-1-Liam.Howlett@oracle.com
[Liam.Howlett@oracle.com: update forking to separate maple state and node]
Link: https://lkml.kernel.org/r/20231106154551.615042-1-Liam.Howlett@oracle.com
[Liam.Howlett@oracle.com: fix mas_prev() state separation code]
Link: https://lkml.kernel.org/r/20231207193319.4025462-1-Liam.Howlett@oracle.com
Link: https://lkml.kernel.org/r/20231101171629.3612299-9-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Wed, 1 Nov 2023 17:16:24 +0000 (13:16 -0400)]
maple_tree: clean up inlines for some functions
There are a few functions which were inlined but are somewhat too large to
inline, so remove the inline key word.
There are also several very small functions which are used in critical
code sections which gcc was not inlining, so make this more strict and use
__always_line for these functions.
Link: https://lkml.kernel.org/r/20231101171629.3612299-8-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Wed, 1 Nov 2023 17:16:23 +0000 (13:16 -0400)]
maple_tree: use cached node end in mas_destroy()
The node end is set during the walk, so use the resulting end instead of
re-fetching it.
Link: https://lkml.kernel.org/r/20231101171629.3612299-7-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Wed, 1 Nov 2023 17:16:22 +0000 (13:16 -0400)]
maple_tree: use cached node end in mas_next()
When looking for the next entry, don't recalculate the node end as it is
now tracked in the maple state.
Link: https://lkml.kernel.org/r/20231101171629.3612299-6-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Wed, 1 Nov 2023 17:16:21 +0000 (13:16 -0400)]
maple_tree: add end of node tracking to the maple state
Analysis of the mas_for_each() iteration showed that there is a
significant time spent finding the end of a node. This time can be
greatly reduced if the end of the node is cached in the maple state. Care
must be taken to update & invalidate as necessary.
Link: https://lkml.kernel.org/r/20231101171629.3612299-5-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Wed, 1 Nov 2023 17:16:20 +0000 (13:16 -0400)]
maple_tree: move debug check to __mas_set_range()
__mas_set_range() was created to shortcut resetting the maple state and a
debug check was added to the caller (the vma iterator) to ensure the
internal maple state remains safe to use. Move the debug check from the
vma iterator into the maple tree itself so other users do not incorrectly
use the advanced maple state modification.
Fallout from this change include a large amount of debug setup needed to
be moved to earlier in the header, and the maple_tree.h radix-tree test
code needed to move the inclusion of the header to after the atomic
define. None of those changes have functional changes.
Link: https://lkml.kernel.org/r/20231101171629.3612299-4-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Wed, 1 Nov 2023 17:16:19 +0000 (13:16 -0400)]
maple_tree: make mas_erase() more robust
mas_erase() may not deal correctly with all maple states. Make the
function more robust by ensuring the state is in one of the two acceptable
states.
Link: https://lkml.kernel.org/r/20231101171629.3612299-3-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Liam R. Howlett [Wed, 1 Nov 2023 17:16:18 +0000 (13:16 -0400)]
maple_tree: remove unnecessary default labels from switch statements
Patch series "maple_tree: iterator state changes".
These patches have some general cleanup and a change to separate the maple
state status tracking from the maple state node.
The maple state status change allows for walks to continue from previous
places when the status needs to be recorded to make logical sense for the
next call to the maple state. For instance, it allows for prev/next to
function in a way that better resembles the linked list. It also allows
switch statements to be used to detect missed states during compile, and
the addition of fast-path "active" state is cleaner as an enum.
While making the status change, perf showed some very small (one line)
functions that were not inlined even with the inline key word. Making
these small functions __always_inline is less expensive according to perf.
As part of that change, some inlines have been dropped from larger
functions.
Perf also showed that the commonly used mas_for_each() iterator was
spending a lot of time finding the end of the node. This series
introduces caching of the end of the node in the maple state (and updating
it during writes). This caching along with the inline changes yielded at
23.25% improvement on the BENCH_MAS_FOR_EACH maple tree test framework
benchmark.
I've also included a change to mtree_range_walk and mtree_lookup_walk to
take advantage of Peng's change [1] to the initial pivot setup.
mmtests did not produce any significant gains.
[1] https://lore.kernel.org/all/
20230711035444.526-1-zhangpeng.00@bytedance.com/T/#u
This patch (of 12):
Removing the default types from the switch statements will cause compile
warnings on missing cases.
Link: https://lkml.kernel.org/r/20231101171629.3612299-2-Liam.Howlett@oracle.com
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Suggested-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
projects / linux-2.6-microblaze.git / log