diff options
Diffstat (limited to 'Documentation/admin-guide/sysctl')
-rw-r--r-- | Documentation/admin-guide/sysctl/abi.rst | 2 | ||||
-rw-r--r-- | Documentation/admin-guide/sysctl/kernel.rst | 61 | ||||
-rw-r--r-- | Documentation/admin-guide/sysctl/vm.rst | 53 |
3 files changed, 63 insertions, 53 deletions
diff --git a/Documentation/admin-guide/sysctl/abi.rst b/Documentation/admin-guide/sysctl/abi.rst index 77b1d1b2ad42..4e6db0a2a4c0 100644 --- a/Documentation/admin-guide/sysctl/abi.rst +++ b/Documentation/admin-guide/sysctl/abi.rst @@ -11,7 +11,7 @@ Documentation for /proc/sys/abi/ Copyright (c) 2020, Stephen Kitt -For general info, see :doc:`index`. +For general info, see Documentation/admin-guide/sysctl/index.rst. ------------------------------------------------------------------------------ diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst index 68b21395a743..426162009ce9 100644 --- a/Documentation/admin-guide/sysctl/kernel.rst +++ b/Documentation/admin-guide/sysctl/kernel.rst @@ -9,7 +9,8 @@ Copyright (c) 1998, 1999, Rik van Riel <riel@nl.linux.org> Copyright (c) 2009, Shen Feng<shen@cn.fujitsu.com> -For general info and legal blurb, please look in :doc:`index`. +For general info and legal blurb, please look in +Documentation/admin-guide/sysctl/index.rst. ------------------------------------------------------------------------------ @@ -54,7 +55,7 @@ free space valid for 30 seconds. acpi_video_flags ================ -See :doc:`/power/video`. This allows the video resume mode to be set, +See Documentation/power/video.rst. This allows the video resume mode to be set, in a similar fashion to the ``acpi_sleep`` kernel parameter, by combining the following values: @@ -89,7 +90,7 @@ is 0x15 and the full version number is 0x234, this file will contain the value 340 = 0x154. See the ``type_of_loader`` and ``ext_loader_type`` fields in -:doc:`/x86/boot` for additional information. +Documentation/x86/boot.rst for additional information. bootloader_version (x86 only) @@ -99,7 +100,7 @@ The complete bootloader version number. In the example above, this file will contain the value 564 = 0x234. See the ``type_of_loader`` and ``ext_loader_ver`` fields in -:doc:`/x86/boot` for additional information. +Documentation/x86/boot.rst for additional information. bpf_stats_enabled @@ -269,7 +270,7 @@ see the ``hostname(1)`` man page. firmware_config =============== -See :doc:`/driver-api/firmware/fallback-mechanisms`. +See Documentation/driver-api/firmware/fallback-mechanisms.rst. The entries in this directory allow the firmware loader helper fallback to be controlled: @@ -297,7 +298,7 @@ crashes and outputting them to a serial console. ftrace_enabled, stack_tracer_enabled ==================================== -See :doc:`/trace/ftrace`. +See Documentation/trace/ftrace.rst. hardlockup_all_cpu_backtrace @@ -325,7 +326,7 @@ when a hard lockup is detected. 1 Panic on hard lockup. = =========================== -See :doc:`/admin-guide/lockup-watchdogs` for more information. +See Documentation/admin-guide/lockup-watchdogs.rst for more information. This can also be set using the nmi_watchdog kernel parameter. @@ -333,7 +334,12 @@ hotplug ======= Path for the hotplug policy agent. -Default value is "``/sbin/hotplug``". +Default value is ``CONFIG_UEVENT_HELPER_PATH``, which in turn defaults +to the empty string. + +This file only exists when ``CONFIG_UEVENT_HELPER`` is enabled. Most +modern systems rely exclusively on the netlink-based uevent source and +don't need this. hung_task_all_cpu_backtrace @@ -582,7 +588,8 @@ in a KVM virtual machine. This default can be overridden by adding:: nmi_watchdog=1 -to the guest kernel command line (see :doc:`/admin-guide/kernel-parameters`). +to the guest kernel command line (see +Documentation/admin-guide/kernel-parameters.rst). numa_balancing @@ -1067,7 +1074,7 @@ that support this feature. real-root-dev ============= -See :doc:`/admin-guide/initrd`. +See Documentation/admin-guide/initrd.rst. reboot-cmd (SPARC only) @@ -1088,6 +1095,13 @@ Model available). If your platform happens to meet the requirements for EAS but you do not want to use it, change this value to 0. +task_delayacct +=============== + +Enables/disables task delay accounting (see +:doc:`accounting/delay-accounting.rst`). Enabling this feature incurs +a small amount of overhead in the scheduler but is useful for debugging +and performance tuning. It is required by some tools such as iotop. sched_schedstats ================ @@ -1154,7 +1168,7 @@ will take effect. seccomp ======= -See :doc:`/userspace-api/seccomp_filter`. +See Documentation/userspace-api/seccomp_filter.rst. sg-big-buff @@ -1283,11 +1297,11 @@ This parameter can be used to control the soft lockup detector. = ================================= The soft lockup detector monitors CPUs for threads that are hogging the CPUs -without rescheduling voluntarily, and thus prevent the 'watchdog/N' threads -from running. The mechanism depends on the CPUs ability to respond to timer -interrupts which are needed for the 'watchdog/N' threads to be woken up by -the watchdog timer function, otherwise the NMI watchdog — if enabled — can -detect a hard lockup condition. +without rescheduling voluntarily, and thus prevent the 'migration/N' threads +from running, causing the watchdog work fail to execute. The mechanism depends +on the CPUs ability to respond to timer interrupts which are needed for the +watchdog work to be queued by the watchdog timer function, otherwise the NMI +watchdog — if enabled — can detect a hard lockup condition. stack_erasing @@ -1325,7 +1339,7 @@ the boot PROM. sysrq ===== -See :doc:`/admin-guide/sysrq`. +See Documentation/admin-guide/sysrq.rst. tainted @@ -1355,15 +1369,16 @@ ORed together. The letters are seen in "Tainted" line of Oops reports. 131072 `(T)` The kernel was built with the struct randomization plugin ====== ===== ============================================================== -See :doc:`/admin-guide/tainted-kernels` for more information. +See Documentation/admin-guide/tainted-kernels.rst for more information. Note: writes to this sysctl interface will fail with ``EINVAL`` if the kernel is booted with the command line option ``panic_on_taint=<bitmask>,nousertaint`` and any of the ORed together values being written to ``tainted`` match with the bitmask declared on panic_on_taint. - See :doc:`/admin-guide/kernel-parameters` for more details on that particular - kernel command line option and its optional ``nousertaint`` switch. + See Documentation/admin-guide/kernel-parameters.rst for more details on + that particular kernel command line option and its optional + ``nousertaint`` switch. threads-max =========== @@ -1387,7 +1402,7 @@ If a value outside of this range is written to ``threads-max`` an traceoff_on_warning =================== -When set, disables tracing (see :doc:`/trace/ftrace`) when a +When set, disables tracing (see Documentation/trace/ftrace.rst) when a ``WARN()`` is hit. @@ -1407,8 +1422,8 @@ will send them to printk() again. This only works if the kernel was booted with ``tp_printk`` enabled. -See :doc:`/admin-guide/kernel-parameters` and -:doc:`/trace/boottime-trace`. +See Documentation/admin-guide/kernel-parameters.rst and +Documentation/trace/boottime-trace.rst. .. _unaligned-dump-stack: diff --git a/Documentation/admin-guide/sysctl/vm.rst b/Documentation/admin-guide/sysctl/vm.rst index 586cd4b86428..5e795202111f 100644 --- a/Documentation/admin-guide/sysctl/vm.rst +++ b/Documentation/admin-guide/sysctl/vm.rst @@ -25,7 +25,6 @@ files can be found in mm/swap.c. Currently, these files are in /proc/sys/vm: - admin_reserve_kbytes -- block_dump - compact_memory - compaction_proactiveness - compact_unevictable_allowed @@ -64,7 +63,7 @@ Currently, these files are in /proc/sys/vm: - overcommit_ratio - page-cluster - panic_on_oom -- percpu_pagelist_fraction +- percpu_pagelist_high_fraction - stat_interval - stat_refresh - numa_stat @@ -106,13 +105,6 @@ On x86_64 this is about 128MB. Changing this takes effect whenever an application requests memory. -block_dump -========== - -block_dump enables block I/O debugging when set to a nonzero value. More -information on block I/O debugging is in Documentation/admin-guide/laptops/laptop-mode.rst. - - compact_memory ============== @@ -126,7 +118,8 @@ compaction_proactiveness This tunable takes a value in the range [0, 100] with a default value of 20. This tunable determines how aggressively compaction is done in the -background. Setting it to 0 disables proactive compaction. +background. Write of a non zero value to this tunable will immediately +trigger the proactive compaction. Setting it to 0 disables proactive compaction. Note that compaction has a non-trivial system-wide impact as pages belonging to different processes are moved around, which could also lead @@ -790,22 +783,24 @@ panic_on_oom=2+kdump gives you very strong tool to investigate why oom happens. You can get snapshot. -percpu_pagelist_fraction -======================== +percpu_pagelist_high_fraction +============================= -This is the fraction of pages at most (high mark pcp->high) in each zone that -are allocated for each per cpu page list. The min value for this is 8. It -means that we don't allow more than 1/8th of pages in each zone to be -allocated in any single per_cpu_pagelist. This entry only changes the value -of hot per cpu pagelists. User can specify a number like 100 to allocate -1/100th of each zone to each per cpu page list. +This is the fraction of pages in each zone that are can be stored to +per-cpu page lists. It is an upper boundary that is divided depending +on the number of online CPUs. The min value for this is 8 which means +that we do not allow more than 1/8th of pages in each zone to be stored +on per-cpu page lists. This entry only changes the value of hot per-cpu +page lists. A user can specify a number like 100 to allocate 1/100th of +each zone between per-cpu lists. -The batch value of each per cpu pagelist is also updated as a result. It is -set to pcp->high/4. The upper limit of batch is (PAGE_SHIFT * 8) +The batch value of each per-cpu page list remains the same regardless of +the value of the high fraction so allocation latencies are unaffected. -The initial value is zero. Kernel does not use this value at boot time to set -the high water marks for each per cpu page list. If the user writes '0' to this -sysctl, it will revert to this default behavior. +The initial value is zero. Kernel uses this value to set the high pcp->high +mark based on the low watermark for the zone and the number of local +online CPUs. If the user writes '0' to this sysctl, it will revert to +this default behavior. stat_interval @@ -936,12 +931,12 @@ allocations, THP and hugetlbfs pages. To make it sensible with respect to the watermark_scale_factor parameter, the unit is in fractions of 10,000. The default value of -15,000 on !DISCONTIGMEM configurations means that up to 150% of the high -watermark will be reclaimed in the event of a pageblock being mixed due -to fragmentation. The level of reclaim is determined by the number of -fragmentation events that occurred in the recent past. If this value is -smaller than a pageblock then a pageblocks worth of pages will be reclaimed -(e.g. 2MB on 64-bit x86). A boost factor of 0 will disable the feature. +15,000 means that up to 150% of the high watermark will be reclaimed in the +event of a pageblock being mixed due to fragmentation. The level of reclaim +is determined by the number of fragmentation events that occurred in the +recent past. If this value is smaller than a pageblock then a pageblocks +worth of pages will be reclaimed (e.g. 2MB on 64-bit x86). A boost factor +of 0 will disable the feature. watermark_scale_factor |