diff options
Diffstat (limited to 'kernel/Documentation/sysctl')
| -rw-r--r-- | kernel/Documentation/sysctl/kernel.txt | 37 | ||||
| -rw-r--r-- | kernel/Documentation/sysctl/net.txt | 16 | ||||
| -rw-r--r-- | kernel/Documentation/sysctl/vm.txt | 16 |
3 files changed, 52 insertions, 17 deletions
diff --git a/kernel/Documentation/sysctl/kernel.txt b/kernel/Documentation/sysctl/kernel.txt index c831001c4..af70d1541 100644 --- a/kernel/Documentation/sysctl/kernel.txt +++ b/kernel/Documentation/sysctl/kernel.txt @@ -33,6 +33,7 @@ show up in /proc/sys/kernel: - domainname - hostname - hotplug +- hardlockup_all_cpu_backtrace - hung_task_panic - hung_task_check_count - hung_task_timeout_secs @@ -197,8 +198,8 @@ core_pattern is used to specify a core dumpfile pattern name. %P global pid (init PID namespace) %i tid %I global tid (init PID namespace) - %u uid - %g gid + %u uid (in initial user namespace) + %g gid (in initial user namespace) %d dump mode, matches PR_SET_DUMPABLE and /proc/sys/fs/suid_dumpable %s signal number @@ -293,6 +294,17 @@ domain names are in general different. For a detailed discussion see the hostname(1) man page. ============================================================== +hardlockup_all_cpu_backtrace: + +This value controls the hard lockup detector behavior when a hard +lockup condition is detected as to whether or not to gather further +debug information. If enabled, arch-specific all-CPU stack dumping +will be initiated. + +0: do nothing. This is the default behavior. + +1: on detection capture more debug information. +============================================================== hotplug: @@ -923,6 +935,27 @@ and nmi_watchdog. ============================================================== +watchdog_cpumask: + +This value can be used to control on which cpus the watchdog may run. +The default cpumask is all possible cores, but if NO_HZ_FULL is +enabled in the kernel config, and cores are specified with the +nohz_full= boot argument, those cores are excluded by default. +Offline cores can be included in this mask, and if the core is later +brought online, the watchdog will be started based on the mask value. + +Typically this value would only be touched in the nohz_full case +to re-enable cores that by default were not running the watchdog, +if a kernel lockup was suspected on those cores. + +The argument value is the standard cpulist format for cpumasks, +so for example to enable the watchdog on cores 0, 2, 3, and 4 you +might say: + + echo 0,2-4 > /proc/sys/kernel/watchdog_cpumask + +============================================================== + watchdog_thresh: This value can be used to control the frequency of hrtimer and NMI diff --git a/kernel/Documentation/sysctl/net.txt b/kernel/Documentation/sysctl/net.txt index 6294b5186..809ab6efc 100644 --- a/kernel/Documentation/sysctl/net.txt +++ b/kernel/Documentation/sysctl/net.txt @@ -54,13 +54,15 @@ default_qdisc -------------- The default queuing discipline to use for network devices. This allows -overriding the default queue discipline of pfifo_fast with an -alternative. Since the default queuing discipline is created with the -no additional parameters so is best suited to queuing disciplines that -work well without configuration like stochastic fair queue (sfq), -CoDel (codel) or fair queue CoDel (fq_codel). Don't use queuing disciplines -like Hierarchical Token Bucket or Deficit Round Robin which require setting -up classes and bandwidths. +overriding the default of pfifo_fast with an alternative. Since the default +queuing discipline is created without additional parameters so is best suited +to queuing disciplines that work well without configuration like stochastic +fair queue (sfq), CoDel (codel) or fair queue CoDel (fq_codel). Don't use +queuing disciplines like Hierarchical Token Bucket or Deficit Round Robin +which require setting up classes and bandwidths. Note that physical multiqueue +interfaces still use mq as root qdisc, which in turn uses this default for its +leaves. Virtual devices (like e.g. lo or veth) ignore this setting and instead +default to noqueue. Default: pfifo_fast busy_read diff --git a/kernel/Documentation/sysctl/vm.txt b/kernel/Documentation/sysctl/vm.txt index 9832ec52f..f72370b44 100644 --- a/kernel/Documentation/sysctl/vm.txt +++ b/kernel/Documentation/sysctl/vm.txt @@ -225,11 +225,11 @@ with your system. To disable them, echo 4 (bit 3) into drop_caches. extfrag_threshold This parameter affects whether the kernel will compact memory or direct -reclaim to satisfy a high-order allocation. /proc/extfrag_index shows what -the fragmentation index for each order is in each zone in the system. Values -tending towards 0 imply allocations would fail due to lack of memory, -values towards 1000 imply failures are due to fragmentation and -1 implies -that the allocation will succeed as long as watermarks are met. +reclaim to satisfy a high-order allocation. The extfrag/extfrag_index file in +debugfs shows what the fragmentation index for each order is in each zone in +the system. Values tending towards 0 imply allocations would fail due to lack +of memory, values towards 1000 imply failures are due to fragmentation and -1 +implies that the allocation will succeed as long as watermarks are met. The kernel will not compact memory in a zone if the fragmentation index is <= extfrag_threshold. The default value is 500. @@ -349,7 +349,7 @@ zone[i]'s protection[j] is calculated by following expression. (i < j): zone[i]->protection[j] - = (total sums of present_pages from zone[i+1] to zone[j] on the node) + = (total sums of managed_pages from zone[i+1] to zone[j] on the node) / lowmem_reserve_ratio[i]; (i = j): (should not be protected. = 0; @@ -360,7 +360,7 @@ The default values of lowmem_reserve_ratio[i] are 256 (if zone[i] means DMA or DMA32 zone) 32 (others). As above expression, they are reciprocal number of ratio. -256 means 1/256. # of protection pages becomes about "0.39%" of total present +256 means 1/256. # of protection pages becomes about "0.39%" of total managed pages of higher zones on the node. If you would like to protect more pages, smaller values are effective. @@ -639,7 +639,7 @@ and don't use much of it. The default value is 0. See Documentation/vm/overcommit-accounting and -security/commoncap.c::cap_vm_enough_memory() for more information. +mm/mmap.c::__vm_enough_memory() for more information. ============================================================== |