clocksource: Limit number of CPUs checked for clock synchronization

[linux-2.6-microblaze.git] / Documentation / admin-guide / kernel-parameters.txt

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 02470ba..9ec9ea1 100644 (file)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -581,6 +581,22 @@
                        loops can be debugged more effectively on production
                        systems.
 
+       clocksource.max_cswd_read_retries= [KNL]
+                       Number of clocksource_watchdog() retries due to
+                       external delays before the clock will be marked
+                       unstable.  Defaults to three retries, that is,
+                       four attempts to read the clock under test.
+
+       clocksource.verify_n_cpus= [KNL]
+                       Limit the number of CPUs checked for clocksources
+                       marked with CLOCK_SOURCE_VERIFY_PERCPU that
+                       are marked unstable due to excessive skew.
+                       A negative value says to check all CPUs, while
+                       zero says not to check any.  Values larger than
+                       nr_cpu_ids are silently truncated to nr_cpu_ids.
+                       The actual CPUs are chosen randomly, with
+                       no replacement if the same CPU is chosen twice.
+
        clearcpuid=BITNUM[,BITNUM...] [X86]
                        Disable CPUID feature X for the kernel. See
                        arch/x86/include/asm/cpufeatures.h for the valid bit
@@ -1469,6 +1485,12 @@
                        Don't use this when you are not running on the
                        android emulator
 
+       gpio-mockup.gpio_mockup_ranges
+                       [HW] Sets the ranges of gpiochip of for this device.
+                       Format: <start1>,<end1>,<start2>,<end2>...
+       gpio-mockup.gpio_mockup_named_lines
+                       [HW] Let the driver know GPIO lines should be named.
+
        gpt             [EFI] Forces disk with valid GPT signature but
                        invalid Protective MBR to be treated as GPT. If the
                        primary GPT is corrupted, it enables the backup/alternate
@@ -1492,10 +1514,6 @@
                        Format: <unsigned int> such that (rxsize & ~0x1fffc0) == 0.
                        Default: 1024
 
-       gpio-mockup.gpio_mockup_ranges
-                       [HW] Sets the ranges of gpiochip of for this device.
-                       Format: <start1>,<end1>,<start2>,<end2>...
-
        hardlockup_all_cpu_backtrace=
                        [KNL] Should the hard-lockup detector generate
                        backtraces on all cpus.
@@ -1833,6 +1851,18 @@
                        initcall functions.  Useful for debugging built-in
                        modules and initcalls.
 
+       initramfs_async= [KNL]
+                       Format: <bool>
+                       Default: 1
+                       This parameter controls whether the initramfs
+                       image is unpacked asynchronously, concurrently
+                       with devices being probed and
+                       initialized. This should normally just work,
+                       but as a debugging aid, one can get the
+                       historical behaviour of the initramfs
+                       unpacking being completed before device_ and
+                       late_ initcalls.
+
        initrd=         [BOOT] Specify the location of the initial ramdisk
 
        initrdmem=      [KNL] Specify a physical address and size from which to
@@ -2802,7 +2832,24 @@
                        seconds.  Use this parameter to check at some
                        other rate.  0 disables periodic checking.
 
-       memtest=        [KNL,X86,ARM,PPC] Enable memtest
+       memory_hotplug.memmap_on_memory
+                       [KNL,X86,ARM] Boolean flag to enable this feature.
+                       Format: {on | off (default)}
+                       When enabled, runtime hotplugged memory will
+                       allocate its internal metadata (struct pages)
+                       from the hotadded memory which will allow to
+                       hotadd a lot of memory without requiring
+                       additional memory to do so.
+                       This feature is disabled by default because it
+                       has some implication on large (e.g. GB)
+                       allocations in some configurations (e.g. small
+                       memory blocks).
+                       The state of the flag can be read in
+                       /sys/module/memory_hotplug/parameters/memmap_on_memory.
+                       Note that even when enabled, there are a few cases where
+                       the feature is not effective.
+
+       memtest=        [KNL,X86,ARM,PPC,RISCV] Enable memtest
                        Format: <integer>
                        default : 0 <disable>
                        Specifies the number of memtest passes to be
@@ -3251,6 +3298,8 @@
 
        nohugeiomap     [KNL,X86,PPC,ARM64] Disable kernel huge I/O mappings.
 
+       nohugevmalloc   [PPC] Disable kernel huge vmalloc mappings.
+
        nosmt           [KNL,S390] Disable symmetric multithreading (SMT).
                        Equivalent to smt=1.