Commit de6fef50 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'cgroup-for-6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup 

Pull cgroup updates from Tejun Heo:

 - The locking around cpuset hotplug processing has always been a bit of
   mess which was worked around by making hotplug processing
   asynchronous. The asynchronity isn't great and led to other issues.

   We tried to make the behavior synchronous a while ago but that led to
   lockdep splats. Waiman took another stab at cleaning up and making it
   synchronous. The patch has been in -next for well over a month and
   there haven't been any complaints, so fingers crossed.

 - Tracepoints added to help understanding rstat lock contentions.

 - A bunch of minor changes - doc updates, code cleanups and selftests.

* tag 'cgroup-for-6.10' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (24 commits)
  cgroup/rstat: add cgroup_rstat_cpu_lock helpers and tracepoints
  selftests/cgroup: Drop define _GNU_SOURCE
  docs: cgroup-v1: Update page cache removal functions
  selftests/cgroup: fix uninitialized variables in test_zswap.c
  selftests/cgroup: cpu_hogger init: use {} instead of {NULL}
  selftests/cgroup: fix clang warnings: uninitialized fd variable
  selftests/cgroup: fix clang build failures for abs() calls
  cgroup/cpuset: Remove outdated comment in sched_partition_write()
  cgroup/cpuset: Fix incorrect top_cpuset flags
  cgroup/cpuset: Avoid clearing CS_SCHED_LOAD_BALANCE twice
  cgroup/cpuset: Statically initialize more members of top_cpuset
  cgroup: Avoid unnecessary looping in cgroup_no_v1()
  cgroup, legacy_freezer: update comment for freezer_css_offline()
  docs, cgroup: add entries for pids to cgroup-v2.rst
  cgroup: don't call cgroup1_pidlist_destroy_all() for v2
  cgroup_freezer: update comment for freezer_css_online()
  cgroup/rstat: desc member cgrp in cgroup_rstat_flush_release
  cgroup/rstat: add cgroup_rstat_lock helpers and tracepoints
  cgroup/pids: Remove superfluous zeroing
  docs: cgroup-v1: Fix description for css_online
  ...
parents f4b0c4b5 21c38a3b

Documentation/admin-guide/cgroup-v1/cgroups.rst

+1 −1
Original line number Diff line number Diff line
@@ -570,7 +570,7 @@ visible to cgroup_for_each_child/descendant_*() iterators. The 
subsystem may choose to fail creation by returning -errno. This

callback can be used to implement reliable state sharing and

propagation along the hierarchy. See the comment on

cgroup_for_each_descendant_pre() for details.

cgroup_for_each_live_descendant_pre() for details.



``void css_offline(struct cgroup *cgrp);``

(cgroup_mutex held by caller)

Documentation/admin-guide/cgroup-v1/memcg_test.rst

+1 −1
Original line number Diff line number Diff line
@@ -102,7 +102,7 @@ Under below explanation, we assume CONFIG_SWAP=y. 
	The logic is very clear. (About migration, see below)



	Note:

	  __remove_from_page_cache() is called by remove_from_page_cache()

	  __filemap_remove_folio() is called by filemap_remove_folio()

	  and __remove_mapping().



6. Shmem(tmpfs) Page Cache

Documentation/admin-guide/cgroup-v2.rst

+24 −7
Original line number Diff line number Diff line
@@ -1058,12 +1058,15 @@ 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
@@ -2190,11 +2193,25 @@ 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. The

	following entries are defined. Unless specified otherwise, a value

	change in this file generates a file modified event.



	  max

		Number of times fork failed because limit was hit.



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

include/linux/cgroup.h

+1 −1
Original line number Diff line number Diff line
@@ -690,7 +690,7 @@ static inline void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen) 
void cgroup_rstat_updated(struct cgroup *cgrp, int cpu);

void cgroup_rstat_flush(struct cgroup *cgrp);

void cgroup_rstat_flush_hold(struct cgroup *cgrp);

void cgroup_rstat_flush_release(void);

void cgroup_rstat_flush_release(struct cgroup *cgrp);



/*

 * Basic resource stats.

include/linux/cpuset.h

+0 −3
Original line number Diff line number Diff line
@@ -70,7 +70,6 @@ extern int cpuset_init(void); 
extern void cpuset_init_smp(void);

extern void cpuset_force_rebuild(void);

extern void cpuset_update_active_cpus(void);

extern void cpuset_wait_for_hotplug(void);

extern void inc_dl_tasks_cs(struct task_struct *task);

extern void dec_dl_tasks_cs(struct task_struct *task);

extern void cpuset_lock(void);
@@ -185,8 +184,6 @@ static inline void cpuset_update_active_cpus(void) 
	partition_sched_domains(1, NULL, NULL);

}



static inline void cpuset_wait_for_hotplug(void) { }



static inline void inc_dl_tasks_cs(struct task_struct *task) { }

static inline void dec_dl_tasks_cs(struct task_struct *task) { }

static inline void cpuset_lock(void) { }