summaryrefslogtreecommitdiffstats
path: root/kernel/Documentation/sysctl
diff options
context:
space:
mode:
Diffstat (limited to 'kernel/Documentation/sysctl')
-rw-r--r--kernel/Documentation/sysctl/kernel.txt37
-rw-r--r--kernel/Documentation/sysctl/net.txt16
-rw-r--r--kernel/Documentation/sysctl/vm.txt16
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.
==============================================================