diff options
Diffstat (limited to 'Documentation/admin-guide/cgroup-v2.rst')
| -rw-r--r-- | Documentation/admin-guide/cgroup-v2.rst | 80 |
1 files changed, 74 insertions, 6 deletions
diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 7bf3f129c68b..3b29005aa981 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -9,7 +9,7 @@ This is the authoritative documentation on the design, interface and conventions of cgroup v2. It describes all userland-visible aspects of cgroup including core and specific controller behaviors. All future changes must be reflected in this document. Documentation for -v1 is available under Documentation/cgroup-v1/. +v1 is available under Documentation/admin-guide/cgroup-v1/. .. CONTENTS @@ -177,6 +177,15 @@ cgroup v2 currently supports the following mount options. ignored on non-init namespace mounts. Please refer to the Delegation section for details. + memory_localevents + + Only populate memory.events with data for the current cgroup, + and not any subtrees. This is legacy behaviour, the default + behaviour without this option is to include subtree counts. + This option is system wide and can only be set on mount or + modified through remount from the init namespace. The mount + option is ignored on non-init namespace mounts. + Organizing Processes and Threads -------------------------------- @@ -696,6 +705,12 @@ Conventions informational files on the root cgroup which end up showing global information available elsewhere shouldn't exist. +- The default time unit is microseconds. If a different unit is ever + used, an explicit unit suffix must be present. + +- A parts-per quantity should use a percentage decimal with at least + two digit fractional part - e.g. 13.40. + - If a controller implements weight based resource distribution, its interface file should be named "weight" and have the range [1, 10000] with 100 as the default. The values are chosen to allow @@ -864,6 +879,8 @@ All cgroup core files are prefixed with "cgroup." populated 1 if the cgroup or its descendants contains any live processes; otherwise, 0. + frozen + 1 if the cgroup is frozen; otherwise, 0. cgroup.max.descendants A read-write single value files. The default is "max". @@ -897,6 +914,31 @@ All cgroup core files are prefixed with "cgroup." A dying cgroup can consume system resources not exceeding limits, which were active at the moment of cgroup deletion. + cgroup.freeze + A read-write single value file which exists on non-root cgroups. + Allowed values are "0" and "1". The default is "0". + + Writing "1" to the file causes freezing of the cgroup and all + descendant cgroups. This means that all belonging processes will + be stopped and will not run until the cgroup will be explicitly + unfrozen. Freezing of the cgroup may take some time; when this action + is completed, the "frozen" value in the cgroup.events control file + will be updated to "1" and the corresponding notification will be + issued. + + A cgroup can be frozen either by its own settings, or by settings + of any ancestor cgroups. If any of ancestor cgroups is frozen, the + cgroup will remain frozen. + + Processes in the frozen cgroup can be killed by a fatal signal. + They also can enter and leave a frozen cgroup: either by an explicit + move by a user, or if freezing of the cgroup races with fork(). + If a process is moved to a frozen cgroup, it stops. If a process is + moved out of a frozen cgroup, it becomes running. + + Frozen status of a cgroup doesn't affect any cgroup tree operations: + it's possible to delete a frozen (and empty) cgroup, as well as + create new sub-cgroups. Controllers =========== @@ -972,7 +1014,7 @@ All time durations are in microseconds. A read-only nested-key file which exists on non-root cgroups. Shows pressure stall information for CPU. See - Documentation/accounting/psi.txt for details. + Documentation/accounting/psi.rst for details. Memory @@ -1104,6 +1146,11 @@ PAGE_SIZE multiple when read back. otherwise, a value change in this file generates a file modified event. + Note that all fields in this file are hierarchical and the + file modified event can be generated due to an event down the + hierarchy. For for the local events at the cgroup level see + memory.events.local. + low The number of times the cgroup is reclaimed due to high memory pressure even though its usage is under @@ -1143,6 +1190,11 @@ PAGE_SIZE multiple when read back. The number of processes belonging to this cgroup killed by any kind of OOM killer. + memory.events.local + Similar to memory.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. + memory.stat A read-only flat-keyed file which exists on non-root cgroups. @@ -1189,6 +1241,10 @@ PAGE_SIZE multiple when read back. Amount of cached filesystem data that was modified and is currently being written back to disk + anon_thp + Amount of memory used in anonymous mappings backed by + transparent hugepages + inactive_anon, active_anon, inactive_file, active_file, unevictable Amount of memory, swap-backed and filesystem-backed, on the internal memory management lists used by the @@ -1248,6 +1304,18 @@ PAGE_SIZE multiple when read back. Amount of reclaimed lazyfree pages + thp_fault_alloc + + Number of transparent hugepages which were allocated to satisfy + a page fault, including COW faults. This counter is not present + when CONFIG_TRANSPARENT_HUGEPAGE is not set. + + thp_collapse_alloc + + Number of transparent hugepages which were allocated to allow + collapsing an existing range of pages. This counter is not + present when CONFIG_TRANSPARENT_HUGEPAGE is not set. + memory.swap.current A read-only single value file which exists on non-root cgroups. @@ -1287,7 +1355,7 @@ PAGE_SIZE multiple when read back. A read-only nested-key file which exists on non-root cgroups. Shows pressure stall information for memory. See - Documentation/accounting/psi.txt for details. + Documentation/accounting/psi.rst for details. Usage Guidelines @@ -1430,7 +1498,7 @@ IO Interface Files A read-only nested-key file which exists on non-root cgroups. Shows pressure stall information for IO. See - Documentation/accounting/psi.txt for details. + Documentation/accounting/psi.rst for details. Writeback @@ -1503,7 +1571,7 @@ protected workload. The limits are only applied at the peer level in the hierarchy. This means that in the diagram below, only groups A, B, and C will influence each other, and -groups D and F will influence each other. Group G will influence nobody. +groups D and F will influence each other. Group G will influence nobody:: [root] / | \ @@ -2056,7 +2124,7 @@ following two functions. a queue (device) has been associated with the bio and before submission. - wbc_account_io(@wbc, @page, @bytes) + wbc_account_cgroup_owner(@wbc, @page, @bytes) Should be called for each data segment being written out. While this function doesn't care exactly when it's called during the writeback session, it's the easiest and most |