Commit Graph

13 Commits

Author SHA1 Message Date
David Rientjes b6bb981149 mm, vmpressure: pass-through notification support
By default, vmpressure events are not pass-through, i.e.  they propagate
up through the memcg hierarchy until an event notifier is found for any
threshold level.

This presents a difficulty when a thread waiting on a read(2) for a
vmpressure event cannot distinguish between local memory pressure and
memory pressure in a descendant memcg, especially when that thread may
not control the memcg hierarchy.

Consider a user-controlled child memcg with a smaller limit than a
top-level memcg controlled by the "Activity Manager" specified in
Documentation/cgroup-v1/memory.txt.  It may register for memory pressure
notification for descendant memcgs to make a policy decision: oom kill a
low priority job, increase the limit, decrease other limits, etc.  If it
registers for memory pressure notification on the top-level memcg, it
currently cannot distinguish between memory pressure in its own memcg or
a descendant memcg, which is user-controlled.

Conversely, if a user registers for memory pressure notification on
their own descendant memcg, the Activity Manager does not receive any
pressure notification for that child memcg hierarchy.  Vmpressure events
are not received for ancestor memcgs if the memcg experiencing pressure
have notifiers registered, perhaps outside the knowledge of the thread
waiting on read(2) at the top level.

Both of these are consequences of vmpressure notification not being
pass-through.

This implements a pass-through behavior for vmpressure events.  When
writing to control.event_control, vmpressure event handlers may
optionally specify a mode.  There are two new modes:

 - "hierarchy": always propagate memory pressure events up the hierarchy
   regardless if descendant memcgs have their own notifiers registered,
   and

 - "local": only receive notifications when the memcg for which the
   event is registered experiences memory pressure.

Of course, processes may register for one notification of "low,local",
for example, and another for "low".

If no mode is specified, the current behavior is maintained for
backwards compatibility.

See the change to Documentation/cgroup-v1/memory.txt for full
specification.

[dan.carpenter@oracle.com: free the same pointer we allocated]
  Link: http://lkml.kernel.org/r/20170613191820.GA20003@elgon.mountain
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1705311421320.8946@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Anton Vorontsov <anton@enomsg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-07-10 16:32:31 -07:00
Linus Torvalds f7878dc3a9 Merge branch 'for-4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
 "Several noteworthy changes.

   - Parav's rdma controller is finally merged. It is very straight
     forward and can limit the abosolute numbers of common rdma
     constructs used by different cgroups.

   - kernel/cgroup.c got too chubby and disorganized. Created
     kernel/cgroup/ subdirectory and moved all cgroup related files
     under kernel/ there and reorganized the core code. This hurts for
     backporting patches but was long overdue.

   - cgroup v2 process listing reimplemented so that it no longer
     depends on allocating a buffer large enough to cache the entire
     result to sort and uniq the output. v2 has always mangled the sort
     order to ensure that users don't depend on the sorted output, so
     this shouldn't surprise anybody. This makes the pid listing
     functions use the same iterators that are used internally, which
     have to have the same iterating capabilities anyway.

   - perf cgroup filtering now works automatically on cgroup v2. This
     patch was posted a long time ago but somehow fell through the
     cracks.

   - misc fixes asnd documentation updates"

* 'for-4.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (27 commits)
  kernfs: fix locking around kernfs_ops->release() callback
  cgroup: drop the matching uid requirement on migration for cgroup v2
  cgroup, perf_event: make perf_event controller work on cgroup2 hierarchy
  cgroup: misc cleanups
  cgroup: call subsys->*attach() only for subsystems which are actually affected by migration
  cgroup: track migration context in cgroup_mgctx
  cgroup: cosmetic update to cgroup_taskset_add()
  rdmacg: Fixed uninitialized current resource usage
  cgroup: Add missing cgroup-v2 PID controller documentation.
  rdmacg: Added documentation for rdmacg
  IB/core: added support to use rdma cgroup controller
  rdmacg: Added rdma cgroup controller
  cgroup: fix a comment typo
  cgroup: fix RCU related sparse warnings
  cgroup: move namespace code to kernel/cgroup/namespace.c
  cgroup: rename functions for consistency
  cgroup: move v1 mount functions to kernel/cgroup/cgroup-v1.c
  cgroup: separate out cgroup1_kf_syscall_ops
  cgroup: refactor mount path and clearly distinguish v1 and v2 paths
  cgroup: move cgroup v1 specific code to kernel/cgroup/cgroup-v1.c
  ...
2017-02-27 21:41:08 -08:00
W. Trevor King 43d8808b08 Documentation: cpuset: Fix 'cpuset.tasks' -> 'tasks'
This looks like it was accidentally caught up in e21a05cb (doc:
cpuset: Update the cpuset flag file, 2010-02-24).

While I'm touching the line, also fix the posessive "cpusets" ->
"cpuset's".

Signed-off-by: W. Trevor King <wking@tremily.us>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2017-01-13 11:04:45 -07:00
Parav Pandit 9c1e67f941 rdmacg: Added documentation for rdmacg
Added documentation for v1 and v2 version describing high
level design and usage examples on using rdma controller.

Signed-off-by: Parav Pandit <pandit.parav@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2017-01-10 11:14:27 -05:00
Mauro Carvalho Chehab 8c27ceff36 docs: fix locations of several documents that got moved
The previous patch renamed several files that are cross-referenced
along the Kernel documentation. Adjust the links to point to
the right places.

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
2016-10-24 08:12:35 -02:00
Linus Torvalds 52ddb7e9dd Three fixes for the docs build, including removing an annoying warning on
"make help" if sphinx isn't present.
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Merge tag 'doc-4.8-fixes' of git://git.lwn.net/linux

Pull documentation fixes from Jonathan Corbet:
 "Three fixes for the docs build, including removing an annoying warning
  on 'make help' if sphinx isn't present"

* tag 'doc-4.8-fixes' of git://git.lwn.net/linux:
  DocBook: use DOCBOOKS="" to ignore DocBooks instead of IGNORE_DOCBOOKS=1
  Documenation: update cgroup's document path
  Documentation/sphinx: do not warn about missing tools in 'make help'
2016-08-07 10:23:17 -04:00
seokhoon.yoon 09c3bcce7c Documenation: update cgroup's document path
cgroup's document path is changed to "cgroup-v1". update it.

Signed-off-by: seokhoon.yoon <iamyooon@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2016-08-03 15:43:58 -06:00
Mel Gorman a52633d8e9 mm, vmscan: move lru_lock to the node
Node-based reclaim requires node-based LRUs and locking.  This is a
preparation patch that just moves the lru_lock to the node so later
patches are easier to review.  It is a mechanical change but note this
patch makes contention worse because the LRU lock is hotter and direct
reclaim and kswapd can contend on the same lock even when reclaiming
from different zones.

Link: http://lkml.kernel.org/r/1467970510-21195-3-git-send-email-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Rik van Riel <riel@surriel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-07-28 16:07:41 -07:00
Qiang Huang 2bdbc5bc16 Documentation/memcg: update kmem limit doc as codes behavior
The restriction of kmem setting is not there anymore because the
accounting is enabled by default even in the cgroup v1 - see
b313aeee25 ("mm: memcontrol: enable kmem accounting for all
cgroups in the legacy hierarchy").

Update docs accordingly.

Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2016-05-14 10:12:45 -06:00
Linus Torvalds 6b5f04b6cf Merge branch 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup updates from Tejun Heo:
 "cgroup changes for v4.6-rc1.  No userland visible behavior changes in
  this pull request.  I'll send out a separate pull request for the
  addition of cgroup namespace support.

   - The biggest change is the revamping of cgroup core task migration
     and controller handling logic.  There are quite a few places where
     controllers and tasks are manipulated.  Previously, many of those
     places implemented custom operations for each specific use case
     assuming specific starting conditions.  While this worked, it makes
     the code fragile and difficult to follow.

     The bulk of this pull request restructures these operations so that
     most related operations are performed through common helpers which
     implement recursive (subtrees are always processed consistently)
     and idempotent (they make cgroup hierarchy converge to the target
     state rather than performing operations assuming specific starting
     conditions).  This makes the code a lot easier to understand,
     verify and extend.

   - Implicit controller support is added.  This is primarily for using
     perf_event on the v2 hierarchy so that perf can match cgroup v2
     path without requiring the user to do anything special.  The kernel
     portion of perf_event changes is acked but userland changes are
     still pending review.

   - cgroup_no_v1= boot parameter added to ease testing cgroup v2 in
     certain environments.

   - There is a regression introduced during v4.4 devel cycle where
     attempts to migrate zombie tasks can mess up internal object
     management.  This was fixed earlier this week and included in this
     pull request w/ stable cc'd.

   - Misc non-critical fixes and improvements"

* 'for-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup: (44 commits)
  cgroup: avoid false positive gcc-6 warning
  cgroup: ignore css_sets associated with dead cgroups during migration
  Documentation: cgroup v2: Trivial heading correction.
  cgroup: implement cgroup_subsys->implicit_on_dfl
  cgroup: use css_set->mg_dst_cgrp for the migration target cgroup
  cgroup: make cgroup[_taskset]_migrate() take cgroup_root instead of cgroup
  cgroup: move migration destination verification out of cgroup_migrate_prepare_dst()
  cgroup: fix incorrect destination cgroup in cgroup_update_dfl_csses()
  cgroup: Trivial correction to reflect controller.
  cgroup: remove stale item in cgroup-v1 document INDEX file.
  cgroup: update css iteration in cgroup_update_dfl_csses()
  cgroup: allocate 2x cgrp_cset_links when setting up a new root
  cgroup: make cgroup_calc_subtree_ss_mask() take @this_ss_mask
  cgroup: reimplement rebind_subsystems() using cgroup_apply_control() and friends
  cgroup: use cgroup_apply_enable_control() in cgroup creation path
  cgroup: combine cgroup_mutex locking and offline css draining
  cgroup: factor out cgroup_{apply|finalize}_control() from cgroup_subtree_control_write()
  cgroup: introduce cgroup_{save|propagate|restore}_control()
  cgroup: make cgroup_drain_offline() and cgroup_apply_control_{disable|enable}() recursive
  cgroup: factor out cgroup_apply_control_enable() from cgroup_subtree_control_write()
  ...
2016-03-18 20:25:49 -07:00
Christoph Lameter 93e205a728 fix Christoph's email addresses
There are various email addresses for me throughout the kernel.  Use the
one that will always be valid.

Signed-off-by: Christoph Lameter <cl@linux.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-03-17 15:09:34 -07:00
Haosdent Huang 88bcf65e66 cgroup: remove stale item in cgroup-v1 document INDEX file.
Signed-off-by: Haosdent Huang <haosdent@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
2016-03-04 08:01:47 -05:00
Tejun Heo 6255c46fa0 cgroup: rename cgroup documentations
cgroup-legacy may be too loaded.  Rename the docs so that they're
postfixed with v1 and v2.

* s/cgroup-legacy/cgroup-v1/
* s/cgroup.txt/cgroup-v2.txt/

Signed-off-by: Tejun Heo <tj@kernel.org>
2016-01-11 23:14:51 -05:00