Lines Matching +full:multi +full:- +full:socket
9 conventions of cgroup v2. It describes all userland-visible aspects
12 v1 is available under :ref:`Documentation/admin-guide/cgroup-v1/index.rst <cgroup-v1>`.
17 1-1. Terminology
18 1-2. What is cgroup?
20 2-1. Mounting
21 2-2. Organizing Processes and Threads
22 2-2-1. Processes
23 2-2-2. Threads
24 2-3. [Un]populated Notification
25 2-4. Controlling Controllers
26 2-4-1. Enabling and Disabling
27 2-4-2. Top-down Constraint
28 2-4-3. No Internal Process Constraint
29 2-5. Delegation
30 2-5-1. Model of Delegation
31 2-5-2. Delegation Containment
32 2-6. Guidelines
33 2-6-1. Organize Once and Control
34 2-6-2. Avoid Name Collisions
36 3-1. Weights
37 3-2. Limits
38 3-3. Protections
39 3-4. Allocations
41 4-1. Format
42 4-2. Conventions
43 4-3. Core Interface Files
45 5-1. CPU
46 5-1-1. CPU Interface Files
47 5-2. Memory
48 5-2-1. Memory Interface Files
49 5-2-2. Usage Guidelines
50 5-2-3. Memory Ownership
51 5-3. IO
52 5-3-1. IO Interface Files
53 5-3-2. Writeback
54 5-3-3. IO Latency
55 5-3-3-1. How IO Latency Throttling Works
56 5-3-3-2. IO Latency Interface Files
57 5-3-4. IO Priority
58 5-4. PID
59 5-4-1. PID Interface Files
60 5-5. Cpuset
61 5.5-1. Cpuset Interface Files
62 5-6. Device
63 5-7. RDMA
64 5-7-1. RDMA Interface Files
65 5-8. HugeTLB
66 5.8-1. HugeTLB Interface Files
67 5-8. Misc
68 5-8-1. perf_event
69 5-N. Non-normative information
70 5-N-1. CPU controller root cgroup process behaviour
71 5-N-2. IO controller root cgroup process behaviour
73 6-1. Basics
74 6-2. The Root and Views
75 6-3. Migration and setns(2)
76 6-4. Interaction with Other Namespaces
78 P-1. Filesystem Support for Writeback
81 R-1. Multiple Hierarchies
82 R-2. Thread Granularity
83 R-3. Competition Between Inner Nodes and Threads
84 R-4. Other Interface Issues
85 R-5. Controller Issues and Remedies
86 R-5-1. Memory
93 -----------
102 ---------------
108 cgroup is largely composed of two parts - the core and controllers.
124 hierarchical - if a controller is enabled on a cgroup, it affects all
126 sub-hierarchy of the cgroup. When a controller is enabled on a nested
136 --------
141 # mount -t cgroup2 none $MOUNT_POINT
151 is no longer referenced in its current hierarchy. Because per-cgroup
158 to inter-controller dependencies, other controllers may need to be
180 ignored on non-init namespace mounts. Please refer to the
190 option is ignored on non-init namespace mounts.
199 behavior but is a mount-option to avoid regressing setups
205 --------------------------------
211 A child cgroup can be created by creating a sub-directory::
216 structure. Each cgroup has a read-writable interface file
218 belong to the cgroup one-per-line. The PIDs are not ordered and the
249 0::/test-cgroup/test-cgroup-nested
256 0::/test-cgroup/test-cgroup-nested (deleted)
282 constraint - threaded controllers can be enabled on non-leaf cgroups
306 - As the cgroup will join the parent's resource domain. The parent
309 - When the parent is an unthreaded domain, it must not have any domain
313 Topology-wise, a cgroup can be in an invalid state. Please consider
316 A (threaded domain) - B (threaded) - C (domain, just created)
331 threads in the cgroup. Except that the operations are per-thread
332 instead of per-process, "cgroup.threads" has the same format and
354 between threads in a non-leaf cgroup and its child cgroups. Each
359 --------------------------
361 Each non-root cgroup has a "cgroup.events" file which contains
362 "populated" field indicating whether the cgroup's sub-hierarchy has
366 example, to start a clean-up operation after all processes of a given
367 sub-hierarchy have exited. The populated state updates and
368 notifications are recursive. Consider the following sub-hierarchy
372 A(4) - B(0) - C(1)
382 -----------------------
396 # echo "+cpu +memory -io" > cgroup.subtree_control
405 Consider the following sub-hierarchy. The enabled controllers are
408 A(cpu,memory) - B(memory) - C()
422 controller interface files - anything which doesn't start with
426 Top-down Constraint
429 Resources are distributed top-down and a cgroup can further distribute
431 parent. This means that all non-root "cgroup.subtree_control" files
441 Non-root cgroups can distribute domain resources to their children
456 refer to the Non-normative information section in the Controllers
469 ----------
489 delegated, the user can build sub-hierarchy under the directory,
493 happens in the delegated sub-hierarchy, nothing can escape the
497 cgroups in or nesting depth of a delegated sub-hierarchy; however,
504 A delegated sub-hierarchy is contained in the sense that processes
505 can't be moved into or out of the sub-hierarchy by the delegatee.
508 requiring the following conditions for a process with a non-root euid
512 - The writer must have write access to the "cgroup.procs" file.
514 - The writer must have write access to the "cgroup.procs" file of the
518 processes around freely in the delegated sub-hierarchy it can't pull
519 in from or push out to outside the sub-hierarchy.
525 ~~~~~~~~~~~~~ - C0 - C00
528 ~~~~~~~~~~~~~ - C1 - C10
535 will be denied with -EACCES.
540 is not reachable, the migration is rejected with -ENOENT.
544 ----------
552 inherent trade-offs between migration and various hot paths in terms
558 resource structure once on start-up. Dynamic adjustments to resource
591 -------
597 work-conserving. Due to the dynamic nature, this model is usually
613 ------
616 Limits can be over-committed - the sum of the limits of children can
621 As limits can be over-committed, all configuration combinations are
630 -----------
635 soft boundaries. Protections can also be over-committed in which case
642 As protections can be over-committed, all configuration combinations
646 "memory.low" implements best-effort memory protection and is an
651 -----------
654 resource. Allocations can't be over-committed - the sum of the
661 As allocations can't be over-committed, some configuration
666 "cpu.rt.max" hard-allocates realtime slices and is an example of this
674 ------
679 New-line separated values
687 (when read-only or multiple values can be written at once)
713 -----------
715 - Settings for a single feature should be contained in a single file.
717 - The root cgroup should be exempt from resource control and thus
720 - The default time unit is microseconds. If a different unit is ever
723 - A parts-per quantity should use a percentage decimal with at least
724 two digit fractional part - e.g. 13.40.
726 - If a controller implements weight based resource distribution, its
732 - If a controller implements an absolute resource guarantee and/or
741 - If a setting has a configurable default value and keyed specific
755 # cat cgroup-example-interface-file
761 # echo 125 > cgroup-example-interface-file
765 # echo "default 125" > cgroup-example-interface-file
769 # echo "8:16 170" > cgroup-example-interface-file
773 # echo "8:0 default" > cgroup-example-interface-file
774 # cat cgroup-example-interface-file
778 - For events which are not very high frequency, an interface file
785 --------------------
791 A read-write single value file which exists on non-root
797 - "domain" : A normal valid domain cgroup.
799 - "domain threaded" : A threaded domain cgroup which is
802 - "domain invalid" : A cgroup which is in an invalid state.
806 - "threaded" : A threaded cgroup which is a member of a
813 A read-write new-line separated values file which exists on
817 the cgroup one-per-line. The PIDs are not ordered and the
826 - It must have write access to the "cgroup.procs" file.
828 - It must have write access to the "cgroup.procs" file of the
831 When delegating a sub-hierarchy, write access to this file
839 A read-write new-line separated values file which exists on
843 the cgroup one-per-line. The TIDs are not ordered and the
852 - It must have write access to the "cgroup.threads" file.
854 - The cgroup that the thread is currently in must be in the
857 - It must have write access to the "cgroup.procs" file of the
860 When delegating a sub-hierarchy, write access to this file
864 A read-only space separated values file which exists on all
871 A read-write space separated values file which exists on all
878 Space separated list of controllers prefixed with '+' or '-'
880 name prefixed with '+' enables the controller and '-'
886 A read-only flat-keyed file which exists on non-root cgroups.
898 A read-write single value files. The default is "max".
905 A read-write single value files. The default is "max".
912 A read-only flat-keyed file with the following entries:
930 A read-write single value file which exists on non-root cgroups.
953 create new sub-cgroups.
959 ---
987 A read-only flat-keyed file.
992 - usage_usec
993 - user_usec
994 - system_usec
998 - nr_periods
999 - nr_throttled
1000 - throttled_usec
1003 A read-write single value file which exists on non-root
1009 A read-write single value file which exists on non-root
1012 The nice value is in the range [-20, 19].
1021 A read-write two value file which exists on non-root cgroups.
1033 A read-only nested-key file which exists on non-root cgroups.
1039 A read-write single value file which exists on non-root cgroups.
1054 A read-write single value file which exists on non-root cgroups.
1067 ------
1075 While not completely water-tight, all major memory usages by a given
1080 - Userland memory - page cache and anonymous memory.
1082 - Kernel data structures such as dentries and inodes.
1084 - TCP socket buffers.
1097 A read-only single value file which exists on non-root
1104 A read-write single value file which exists on non-root
1130 A read-write single value file which exists on non-root
1133 Best-effort memory protection. If the memory usage of a
1153 A read-write single value file which exists on non-root
1165 A read-write single value file which exists on non-root
1174 In default configuration regular 0-order allocations always
1179 as -ENOMEM or silently ignore in cases like disk readahead.
1186 A read-write single value file which exists on non-root
1196 Tasks with the OOM protection (oom_score_adj set to -1000)
1204 A read-only flat-keyed file which exists on non-root cgroups.
1218 boundary is over-committed.
1238 considered as an option, e.g. for failed high-order
1251 A read-only flat-keyed file which exists on non-root cgroups.
1254 types of memory, type-specific details, and other information
1263 If the entry has no per-node counter(or not show in the
1264 mempry.numa_stat). We use 'npn'(non-per-node) as the tag
1279 Amount of memory used for storing per-cpu kernel
1286 Amount of cached filesystem data that is swap-backed,
1305 Amount of memory, swap-backed and filesystem-backed,
1311 the value for the foo counter, since the foo counter is type-based, not
1312 list-based.
1323 Amount of memory used for storing in-kernel data
1388 A read-only nested-keyed file which exists on non-root cgroups.
1391 types of memory, type-specific details, and other information
1413 A read-only single value file which exists on non-root
1420 A read-write single value file which exists on non-root
1425 allow userspace to implement custom out-of-memory procedures.
1436 A read-write single value file which exists on non-root
1443 A read-only flat-keyed file which exists on non-root cgroups.
1459 because of running out of swap system-wide or max
1468 A read-only nested-key file which exists on non-root cgroups.
1478 Over-committing on high limit (sum of high limits > available memory)
1492 pressure - how much the workload is being impacted due to lack of
1493 memory - is necessary to determine whether a workload needs more
1507 To which cgroup the area will be charged is in-deterministic; however,
1518 --
1523 only if cfq-iosched is in use and neither scheme is available for
1524 blk-mq devices.
1531 A read-only nested-keyed file.
1551 A read-write nested-keyed file with exists only on the root
1563 enable Weight-based control enable
1595 devices which show wide temporary behavior changes - e.g. a
1606 A read-write nested-keyed file with exists only on the root
1619 model The cost model in use - "linear"
1645 generate device-specific coefficients.
1648 A read-write flat-keyed file which exists on non-root cgroups.
1668 A read-write nested-keyed file which exists on non-root
1682 When writing, any number of nested key-value pairs can be
1707 A read-only nested-key file which exists on non-root cgroups.
1726 writes out dirty pages for the memory domain. Both system-wide and
1727 per-cgroup dirty memory states are examined and the more restrictive
1765 memory controller and system-wide clean memory.
1798 your real setting, setting at 10-15% higher than the value in io.stat.
1808 - Queue depth throttling. This is the number of outstanding IO's a group is
1812 - Artificial delay induction. There are certain types of IO that cannot be
1859 no-change
1862 none-to-rt
1867 restrict-to-be
1878 +-------------+---+
1879 | no-change | 0 |
1880 +-------------+---+
1881 | none-to-rt | 1 |
1882 +-------------+---+
1883 | rt-to-be | 2 |
1884 +-------------+---+
1885 | all-to-idle | 3 |
1886 +-------------+---+
1890 +-------------------------------+---+
1892 +-------------------------------+---+
1893 | IOPRIO_CLASS_RT (real-time) | 1 |
1894 +-------------------------------+---+
1896 +-------------------------------+---+
1898 +-------------------------------+---+
1902 - Translate the I/O priority class policy into a number.
1903 - Change the request I/O priority class into the maximum of the I/O priority
1907 ---
1926 A read-write single value file which exists on non-root
1932 A read-only single value file which exists on all cgroups.
1942 through fork() or clone(). These will return -EAGAIN if the creation
1947 ------
1954 memory placement to reduce cross-node memory access and contention
1965 A read-write multiple values file which exists on non-root
1966 cpuset-enabled cgroups.
1973 The CPU numbers are comma-separated numbers or ranges.
1977 0-4,6,8-10
1980 setting as the nearest cgroup ancestor with a non-empty
1987 A read-only multiple values file which exists on all
1988 cpuset-enabled cgroups.
2004 A read-write multiple values file which exists on non-root
2005 cpuset-enabled cgroups.
2012 The memory node numbers are comma-separated numbers or ranges.
2016 0-1,3
2019 setting as the nearest cgroup ancestor with a non-empty
2027 A read-only multiple values file which exists on all
2028 cpuset-enabled cgroups.
2043 A read-write single value file which exists on non-root
2044 cpuset-enabled cgroups. This flag is owned by the parent cgroup
2049 "root" - a partition root
2050 "member" - a non-root member of a partition
2091 "member" Non-root member of a partition
2117 -----------------
2128 the attempt will succeed or fail with -EPERM.
2133 If the program returns 0, the attempt fails with -EPERM, otherwise
2141 ----
2150 A readwrite nested-keyed file that exists for all the cgroups
2171 A read-only file that describes current resource usage.
2180 -------
2197 A read-only flat-keyed file which exists on non-root cgroups.
2208 ----
2219 Non-normative information
2220 -------------------------
2236 appropriately so the neutral - nice 0 - value is 100 instead of 1024).
2252 ------
2271 The path '/batchjobs/container_id1' can be considered as system-data
2276 # ls -l /proc/self/ns/cgroup
2277 lrwxrwxrwx 1 root root 0 2014-07-15 10:37 /proc/self/ns/cgroup -> cgroup:[4026531835]
2283 # ls -l /proc/self/ns/cgroup
2284 lrwxrwxrwx 1 root root 0 2014-07-15 10:35 /proc/self/ns/cgroup -> cgroup:[4026532183]
2288 When some thread from a multi-threaded process unshares its cgroup
2300 ------------------
2311 # ~/unshare -c # unshare cgroupns in some cgroup
2319 Each process gets its namespace-specific view of "/proc/$PID/cgroup"
2350 ----------------------
2379 ---------------------------------
2382 running inside a non-init cgroup namespace::
2384 # mount -t cgroup2 none $MOUNT_POINT
2391 the view of cgroup hierarchy by namespace-private cgroupfs mount
2404 --------------------------------
2407 address_space_operations->writepage[s]() to annotate bio's using the
2424 super_block by setting SB_I_CGROUPWB in ->s_iflags. This allows for
2441 - Multiple hierarchies including named ones are not supported.
2443 - All v1 mount options are not supported.
2445 - The "tasks" file is removed and "cgroup.procs" is not sorted.
2447 - "cgroup.clone_children" is removed.
2449 - /proc/cgroups is meaningless for v2. Use "cgroup.controllers" file
2457 --------------------
2510 ------------------
2518 Generally, in-process knowledge is available only to the process
2519 itself; thus, unlike service-level organization of processes,
2526 sub-hierarchies and control resource distributions along them. This
2527 effectively raised cgroup to the status of a syscall-like API exposed
2537 that the process would actually be operating on its own sub-hierarchy.
2541 system-management pseudo filesystem. cgroup ended up with interface
2544 individual applications through the ill-defined delegation mechanism
2554 -------------------------------------------
2565 cycles and the number of internal threads fluctuated - the ratios
2581 clearly defined. There were attempts to add ad-hoc behaviors and
2595 ----------------------
2599 was how an empty cgroup was notified - a userland helper binary was
2602 to in-kernel event delivery filtering mechanism further complicating
2624 ------------------------------
2631 global reclaim prefers is opt-in, rather than opt-out. The costs for
2641 becomes self-defeating.
2643 The memory.low boundary on the other hand is a top-down allocated
2681 new limit is met - or the task writing to memory.max is killed.
2690 groups can sabotage swapping by other means - such as referencing its
2691 anonymous memory in a tight loop - and an admin can not assume full