Merge tag 'tif-task_work.arch-2020-12-14' of git://git.kernel.dk/linux-block

[linux-2.6-microblaze.git] / Documentation / admin-guide / sysctl / vm.rst

diff --git a/Documentation/admin-guide/sysctl/vm.rst b/Documentation/admin-guide/sysctl/vm.rst
index 4b9d2e8..e972caa 100644 (file)
--- a/Documentation/admin-guide/sysctl/vm.rst
+++ b/Documentation/admin-guide/sysctl/vm.rst
@@ -27,6 +27,7 @@ Currently, these files are in /proc/sys/vm:
 - admin_reserve_kbytes
 - block_dump
 - compact_memory
+- compaction_proactiveness
 - compact_unevictable_allowed
 - dirty_background_bytes
 - dirty_background_ratio
@@ -37,6 +38,7 @@ Currently, these files are in /proc/sys/vm:
 - dirty_writeback_centisecs
 - drop_caches
 - extfrag_threshold
+- highmem_is_dirtyable
 - hugetlb_shm_group
 - laptop_mode
 - legacy_va_layout
@@ -144,7 +146,7 @@ This should be used on systems where stalls for minor page faults are an
 acceptable trade for large contiguous free memory.  Set to 0 to prevent
 compaction from moving pages that are unevictable.  Default value is 1.
 On CONFIG_PREEMPT_RT the default value is 0 in order to avoid a page fault, due
-to compaction, which would block the task from becomming active until the fault
+to compaction, which would block the task from becoming active until the fault
 is resolved.
 
 
@@ -871,12 +873,17 @@ file-backed pages is less than the high watermark in a zone.
 unprivileged_userfaultfd
 ========================
 
-This flag controls whether unprivileged users can use the userfaultfd
-system calls.  Set this to 1 to allow unprivileged users to use the
-userfaultfd system calls, or set this to 0 to restrict userfaultfd to only
-privileged users (with SYS_CAP_PTRACE capability).
+This flag controls the mode in which unprivileged users can use the
+userfaultfd system calls. Set this to 0 to restrict unprivileged users
+to handle page faults in user mode only. In this case, users without
+SYS_CAP_PTRACE must pass UFFD_USER_MODE_ONLY in order for userfaultfd to
+succeed. Prohibiting use of userfaultfd for handling faults from kernel
+mode may make certain vulnerabilities more difficult to exploit.
 
-The default value is 1.
+Set this to 1 to allow unprivileged users to use the userfaultfd system
+calls without any restrictions.
+
+The default value is 0.
 
 
 user_reserve_kbytes