Pull documentation updates from Jonathan Corbet:
"A fairly routine cycle for docs - lots of typo fixes, some new
documents, and more translations. There's also some LICENSES
adjustments from Thomas"
* tag 'docs-5.1' of git://git.lwn.net/linux: (74 commits)
docs: Bring some order to filesystem documentation
Documentation/locking/lockdep: Drop last two chars of sample states
doc: rcu: Suspicious RCU usage is a warning
docs: driver-api: iio: fix errors in documentation
Documentation/process/howto: Update for 4.x -> 5.x versioning
docs: Explicitly state that the 'Fixes:' tag shouldn't split lines
doc: security: Add kern-doc for lsm_hooks.h
doc: sctp: Merge and clean up rst files
Docs: Correct /proc/stat path
scripts/spdxcheck.py: fix C++ comment style detection
doc: fix typos in license-rules.rst
Documentation: fix admin-guide/README.rst minimum gcc version requirement
doc: process: complete removal of info about -git patches
doc: translations: sync translations 'remove info about -git patches'
perf-security: wrap paragraphs on 72 columns
perf-security: elaborate on perf_events/Perf privileged users
perf-security: document collected perf_events/Perf data categories
perf-security: document perf_events/Perf resource control
sysfs.txt: add note on available attribute macros
docs: kernel-doc: typo "if ... if" -> "if ... is"
...
There is no entry file_mapped in the memory.stat file. This looks like a
simple word flip that's gone unnoticed since 2010 (dc10e281f5,
memcg: update documentation).
Signed-off-by: Florian Schmidt <florian.schmidt@neclab.eu>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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>
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>
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>
