linux-stable.git/include/linux/cgroup-defs.h, branch v5.6.2

cgroup: use cgrp->kn->id as the cgroup ID

2019-11-12T16:18:04+00:00

cgroup ID is currently allocated using a dedicated per-hierarchy idr
and used internally and exposed through tracepoints and bpf.  This is
confusing because there are tracepoints and other interfaces which use
the cgroupfs ino as IDs.

The preceding changes made kn->id exposed as ino as 64bit ino on
supported archs or ino+gen (low 32bits as ino, high gen).  There's no
reason for cgroup to use different IDs.  The kernfs IDs are unique and
userland can easily discover them and map them back to paths using
standard file operations.

This patch replaces cgroup IDs with kernfs IDs.

* cgroup_id() is added and all cgroup ID users are converted to use it.

* kernfs_node creation is moved to earlier during cgroup init so that
  cgroup_id() is available during init.

* While at it, s/cgroup/cgrp/ in psi helpers for consistency.

* Fallback ID value is changed to 1 to be consistent with root cgroup
  ID.

Signed-off-by: Tejun Heo 
Reviewed-by: Greg Kroah-Hartman 
Cc: Namhyung Kim

cgroup: use cgroup->last_bstat instead of cgroup->bstat_pending for consistency

2019-11-06T20:50:15+00:00

cgroup->bstat_pending is used to determine the base stat delta to
propagate to the parent.  While correct, this is different from how
percpu delta is determined for no good reason and the inconsistency
makes the code more difficult to understand.

This patch makes parent propagation delta calculation use the same
method as percpu to global propagation.

* cgroup_base_stat_accumulate() is renamed to cgroup_base_stat_add()
  and cgroup_base_stat_sub() is added.

* percpu propagation calculation is updated to use the above helpers.

* cgroup->bstat_pending is replaced with cgroup->last_bstat and
  updated to use the same calculation as percpu propagation.

Signed-off-by: Tejun Heo

docs: cgroup-v1: add it to the admin-guide book

2019-07-15T14:03:02+00:00

Those files belong to the admin guide, so add them.

Signed-off-by: Mauro Carvalho Chehab

Merge branch 'for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

2019-07-09T04:35:12+00:00

Pull cgroup updates from Tejun Heo:
 "Documentation updates and the addition of cgroup_parse_float() which
  will be used by new controllers including blk-iocost"

* 'for-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  docs: cgroup-v1: convert docs to ReST and rename to *.rst
  cgroup: Move cgroup_parse_float() implementation out of CONFIG_SYSFS
  cgroup: add cgroup_parse_float()

Merge branch 'for-5.2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

2019-06-15T03:46:14+00:00

Pull cgroup fixes from Tejun Heo:
 "This has an unusually high density of tricky fixes:

   - task_get_css() could deadlock when it races against a dying cgroup.

   - cgroup.procs didn't list thread group leaders with live threads.

     This could mislead readers to think that a cgroup is empty when
     it's not. Fixed by making PROCS iterator include dead tasks. I made
     a couple mistakes making this change and this pull request contains
     a couple follow-up patches.

   - When cpusets run out of online cpus, it updates cpusmasks of member
     tasks in bizarre ways. Joel improved the behavior significantly"

* 'for-5.2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cpuset: restore sanity to cpuset_cpus_allowed_fallback()
  cgroup: Fix css_task_iter_advance_css_set() cset skip condition
  cgroup: css_task_iter_skip()'d iterators must be advanced before accessed
  cgroup: Include dying leaders with live threads in PROCS iterations
  cgroup: Implement css_task_iter_skip()
  cgroup: Call cgroup_release() before __exit_signal()
  docs cgroups: add another example size for hugetlb
  cgroup: Use css_tryget() instead of css_tryget_online() in task_get_css()

docs: cgroup-v1: convert docs to ReST and rename to *.rst

2019-06-14T20:29:54+00:00

Convert the cgroup-v1 files to ReST format, in order to
allow a later addition to the admin-guide.

The conversion is actually:
  - add blank lines and identation in order to identify paragraphs;
  - fix tables markups;
  - add some lists markups;
  - mark literal blocks;
  - adjust title markups.

At its new index.rst, let's add a :orphan: while this is not linked to
the main index.rst file, in order to avoid build warnings.

Signed-off-by: Mauro Carvalho Chehab 
Acked-by: Tejun Heo 
Signed-off-by: Tejun Heo

cgroup/bfq: revert bfq.weight symlink change

2019-06-10T09:35:41+00:00

There's some discussion on how to do this the best, and Tejun prefers
that BFQ just create the file itself instead of having cgroups support
a symlink feature.

Hence revert commit 54b7b868e826 and 19e9da9e86c4 for 5.2, and this
can be done properly for 5.3.

Signed-off-by: Jens Axboe

cgroup: let a symlink too be created with a cftype file

2019-06-07T07:29:39+00:00

This commit enables a cftype to have a symlink (of any name) that
points to the file associated with the cftype.

Signed-off-by: Angelo Ruocco 
Signed-off-by: Paolo Valente 
Signed-off-by: Jens Axboe

mm, memcg: consider subtrees in memory.events

2019-06-01T22:51:31+00:00

memory.stat and other files already consider subtrees in their output, and
we should too in order to not present an inconsistent interface.

The current situation is fairly confusing, because people interacting with
cgroups expect hierarchical behaviour in the vein of memory.stat,
cgroup.events, and other files.  For example, this causes confusion when
debugging reclaim events under low, as currently these always read "0" at
non-leaf memcg nodes, which frequently causes people to misdiagnose breach
behaviour.  The same confusion applies to other counters in this file when
debugging issues.

Aggregation is done at write time instead of at read-time since these
counters aren't hot (unlike memory.stat which is per-page, so it does it
at read time), and it makes sense to bundle this with the file
notifications.

After this patch, events are propagated up the hierarchy:

    [root@ktst ~]# cat /sys/fs/cgroup/system.slice/memory.events
    low 0
    high 0
    max 0
    oom 0
    oom_kill 0
    [root@ktst ~]# systemd-run -p MemoryMax=1 true
    Running as unit: run-r251162a189fb4562b9dabfdc9b0422f5.service
    [root@ktst ~]# cat /sys/fs/cgroup/system.slice/memory.events
    low 0
    high 0
    max 7
    oom 1
    oom_kill 1

As this is a change in behaviour, this can be reverted to the old
behaviour by mounting with the `memory_localevents' flag set.  However, we
use the new behaviour by default as there's a lack of evidence that there
are any current users of memory.events that would find this change
undesirable.

akpm: this is a behaviour change, so Cc:stable.  THis is so that
forthcoming distros which use cgroup v2 are more likely to pick up the
revised behaviour.

Link: http://lkml.kernel.org/r/20190208224419.GA24772@chrisdown.name
Signed-off-by: Chris Down 
Acked-by: Johannes Weiner 
Reviewed-by: Shakeel Butt 
Cc: Michal Hocko 
Cc: Tejun Heo 
Cc: Roman Gushchin 
Cc: Dennis Zhou 
Cc: Suren Baghdasaryan 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

cgroup: Include dying leaders with live threads in PROCS iterations

2019-05-31T17:38:58+00:00

CSS_TASK_ITER_PROCS currently iterates live group leaders; however,
this means that a process with dying leader and live threads will be
skipped.  IOW, cgroup.procs might be empty while cgroup.threads isn't,
which is confusing to say the least.

Fix it by making cset track dying tasks and include dying leaders with
live threads in PROCS iteration.

Signed-off-by: Tejun Heo 
Reported-and-tested-by: Topi Miettinen 
Cc: Oleg Nesterov