diff options
Diffstat (limited to 'Documentation/admin-guide/cgroup-v2.rst')
| -rw-r--r-- | Documentation/admin-guide/cgroup-v2.rst | 99 |
1 files changed, 80 insertions, 19 deletions
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 17e6e9565156..86311c2907cd 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -239,6 +239,13 @@ cgroup v2 currently supports the following mount options. will not be tracked by the memory controller (even if cgroup v2 is remounted later on). + pids_localevents + The option restores v1-like behavior of pids.events:max, that is only + local (inside cgroup proper) fork failures are counted. Without this + option pids.events.max represents any pids.max enforcemnt across + cgroup's subtree. + + Organizing Processes and Threads -------------------------------- @@ -1058,12 +1065,15 @@ cpufreq governor about the minimum desired frequency which should always be provided by a CPU, as well as the maximum desired frequency, which should not be exceeded by a CPU. -WARNING: cgroup2 doesn't yet support control of realtime processes and -the cpu controller can only be enabled when all RT processes are in -the root cgroup. Be aware that system management software may already -have placed RT processes into nonroot cgroups during the system boot -process, and these processes may need to be moved to the root cgroup -before the cpu controller can be enabled. +WARNING: cgroup2 doesn't yet support control of realtime processes. For +a kernel built with the CONFIG_RT_GROUP_SCHED option enabled for group +scheduling of realtime processes, the cpu controller can only be enabled +when all RT processes are in the root cgroup. This limitation does +not apply if CONFIG_RT_GROUP_SCHED is disabled. Be aware that system +management software may already have placed RT processes into nonroot +cgroups during the system boot process, and these processes may need +to be moved to the root cgroup before the cpu controller can be enabled +with a CONFIG_RT_GROUP_SCHED enabled kernel. CPU Interface Files @@ -1296,17 +1306,10 @@ PAGE_SIZE multiple when read back. This is a simple interface to trigger memory reclaim in the target cgroup. - This file accepts a single key, the number of bytes to reclaim. - No nested keys are currently supported. - Example:: echo "1G" > memory.reclaim - The interface can be later extended with nested keys to - configure the reclaim behavior. For example, specify the - type of memory to reclaim from (anon, file, ..). - Please note that the kernel can over or under reclaim from the target cgroup. If less bytes are reclaimed than the specified amount, -EAGAIN is returned. @@ -1318,6 +1321,17 @@ PAGE_SIZE multiple when read back. This means that the networking layer will not adapt based on reclaim induced by memory.reclaim. +The following nested keys are defined. + + ========== ================================ + swappiness Swappiness value to reclaim with + ========== ================================ + + Specifying a swappiness value instructs the kernel to perform + the reclaim with that swappiness value. Note that this has the + same semantics as vm.swappiness applied to memcg reclaim with + all the existing limitations and potential future extensions. + memory.peak A read-only single value file which exists on non-root cgroups. @@ -1432,7 +1446,7 @@ PAGE_SIZE multiple when read back. sec_pagetables Amount of memory allocated for secondary page tables, this currently includes KVM mmu allocations on x86 - and arm64. + and arm64 and IOMMU page tables. percpu (npn) Amount of memory used for storing per-cpu kernel @@ -1572,6 +1586,15 @@ PAGE_SIZE multiple when read back. pglazyfreed (npn) Amount of reclaimed lazyfree pages + zswpin + Number of pages moved in to memory from zswap. + + zswpout + Number of pages moved out of memory to zswap. + + zswpwb + Number of pages written from zswap to swap. + thp_fault_alloc (npn) Number of transparent hugepages which were allocated to satisfy a page fault. This counter is not present when CONFIG_TRANSPARENT_HUGEPAGE @@ -2181,11 +2204,31 @@ PID Interface Files Hard limit of number of processes. pids.current - A read-only single value file which exists on all cgroups. + A read-only single value file which exists on non-root cgroups. The number of processes currently in the cgroup and its descendants. + pids.peak + A read-only single value file which exists on non-root cgroups. + + The maximum value that the number of processes in the cgroup and its + descendants has ever reached. + + pids.events + A read-only flat-keyed file which exists on non-root cgroups. Unless + specified otherwise, a value change in this file generates a file + modified event. The following entries are defined. + + max + The number of times the cgroup's total number of processes hit the pids.max + limit (see also pids_localevents). + + pids.events.local + Similar to pids.events but the fields in the file are local + to the cgroup i.e. not hierarchical. The file modified event + generated on this file reflects only the local events. + Organisational operations are not blocked by cgroup policies, so it is possible to have pids.current > pids.max. This can be done by either setting the limit to be smaller than pids.current, or attaching enough @@ -2320,8 +2363,12 @@ Cpuset Interface Files is always a subset of it. Users can manually set it to a value that is different from - "cpuset.cpus". The only constraint in setting it is that the - list of CPUs must be exclusive with respect to its sibling. + "cpuset.cpus". One constraint in setting it is that the list of + CPUs must be exclusive with respect to "cpuset.cpus.exclusive" + of its sibling. If "cpuset.cpus.exclusive" of a sibling cgroup + isn't set, its "cpuset.cpus" value, if set, cannot be a subset + of it to leave at least one CPU available when the exclusive + CPUs are taken away. For a parent cgroup, any one of its exclusive CPUs can only be distributed to at most one of its child cgroups. Having an @@ -2337,8 +2384,8 @@ Cpuset Interface Files cpuset-enabled cgroups. This file shows the effective set of exclusive CPUs that - can be used to create a partition root. The content of this - file will always be a subset of "cpuset.cpus" and its parent's + can be used to create a partition root. The content + of this file will always be a subset of its parent's "cpuset.cpus.exclusive.effective" if its parent is not the root cgroup. It will also be a subset of "cpuset.cpus.exclusive" if it is set. If "cpuset.cpus.exclusive" is not set, it is @@ -2599,6 +2646,15 @@ Miscellaneous controller provides 3 interface files. If two misc resources (res_ res_a 3 res_b 0 + misc.peak + A read-only flat-keyed file shown in all cgroups. It shows the + historical maximum usage of the resources in the cgroup and its + children.:: + + $ cat misc.peak + res_a 10 + res_b 8 + misc.max A read-write flat-keyed file shown in the non root cgroups. Allowed maximum usage of the resources in the cgroup and its children.:: @@ -2628,6 +2684,11 @@ Miscellaneous controller provides 3 interface files. If two misc resources (res_ The number of times the cgroup's resource usage was about to go over the max boundary. + misc.events.local + Similar to misc.events but the fields in the file are local to the + cgroup i.e. not hierarchical. The file modified event generated on + this file reflects only the local events. + Migration and Ownership ~~~~~~~~~~~~~~~~~~~~~~~ |