Introduce a new interface, wmark_scale_factor, which defines the
distance between wmark_high and wmark_low.  The unit is in fractions of
10,000. The default value of 50 means the distance between wmark_high
and wmark_low is 0.5% of the max limit of the cgroup.  The maximum value
is 1000, or 10% of the max limit.

The distance between wmark_low and wmark_high have impact on how hard
memcg kswapd would reclaim.
Reviewed-by: NGavin Shan <shan.gavin@linux.alibaba.com>
Reviewed-by: NXunlei Pang <xlpang@linux.alibaba.com>
Signed-off-by: NYang Shi <yang.shi@linux.alibaba.com>

Currently when memory usage exceeds memory cgroup limit, memory cgroup
just can do sync direct reclaim.  This may incur unexpected stall on
some applications which are sensitive to latency.  Introduce background
async page reclaim mechanism, like what kswapd does.

Define memcg memory usage water mark by introducing wmark_ratio interface,
which is from 0 to 100 and represents percentage of max limit.  The
wmark_high is calculated by (max * wmark_ratio / 100), the wmark_low is
(wmark_high - wmark_high >> 8), which is an empirical value.  If wmark_ratio
is 0, it means water mark is disabled, both wmark_low and wmark_high is max,
which is the default value.

If wmark_ratio is setup, when charging page, if usage is greater than
wmark_high, which means the available memory of memcg is low, a work
would be scheduled to do background page reclaim until memory usage is
reduced to wmark_low if possible.

Define a dedicated unbound workqueue for scheduling water mark reclaim
works.
Reviewed-by: NGavin Shan <shan.gavin@linux.alibaba.com>
Reviewed-by: NXunlei Pang <xlpang@linux.alibaba.com>
Signed-off-by: NYang Shi <yang.shi@linux.alibaba.com>

Remove the address_space ->tree_lock and use the xa_lock newly added to
the radix_tree_root.  Rename the address_space ->page_tree to ->i_pages,
since we don't really care that it's a tree.

[willy@infradead.org: fix nds32, fs/dax.c]
  Link: http://lkml.kernel.org/r/20180406145415.GB20605@bombadil.infradead.orgLink: http://lkml.kernel.org/r/20180313132639.17387-9-willy@infradead.orgSigned-off-by: NMatthew Wilcox <mawilcox@microsoft.com>
Acked-by: NJeff Layton <jlayton@redhat.com>
Cc: Darrick J. Wong <darrick.wong@oracle.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is no entry file_mapped in the memory.stat file. This looks like a
simple word flip that's gone unnoticed since 2010 (dc10e281,
memcg: update documentation).
Signed-off-by: NFlorian Schmidt <florian.schmidt@neclab.eu>
Acked-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

The cgroup-v1 documentation is out of date in a few places:

 * cgroup controllers can no longer be compiled as modules since commit
   3ed80a62 ("cgroup: drop module support"); the functions and fields
   referenced here no longer exist.

 * Controllers need to create of a cgroup_subsys object named
   "<name>_cgrp_subsys" instead of "<name>_subsys" since commit
   073219e9 ("cgroup: clean up cgroup_subsys names and initialization")

Cc: Tejun Heo <tj@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Signed-off-by: NMatt Roper <matthew.d.roper@intel.com>
Signed-off-by: NTejun 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.comSigned-off-by: NDavid Rientjes <rientjes@google.com>
Signed-off-by: NDan 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: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

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: NW. Trevor King <wking@tremily.us>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

Added documentation for v1 and v2 version describing high
level design and usage examples on using rdma controller.
Signed-off-by: NParav Pandit <pandit.parav@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

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: NMauro Carvalho Chehab <mchehab@s-opensource.com>

cgroup's document path is changed to "cgroup-v1". update it.
Signed-off-by: Nseokhoon.yoon <iamyooon@gmail.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

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.netSigned-off-by: NMel Gorman <mgorman@techsingularity.net>
Reviewed-by: NMinchan Kim <minchan@kernel.org>
Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
Acked-by: NVlastimil 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: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus 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
b313aeee ("mm: memcontrol: enable kmem accounting for all
cgroups in the legacy hierarchy").

Update docs accordingly.
Signed-off-by: NQiang Huang <h.huangqiang@huawei.com>
Acked-by: NMichal Hocko <mhocko@suse.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

There are various email addresses for me throughout the kernel.  Use the
one that will always be valid.
Signed-off-by: NChristoph Lameter <cl@linux.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NHaosdent Huang <haosdent@gmail.com>
Signed-off-by: NTejun Heo <tj@kernel.org>

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: NTejun Heo <tj@kernel.org>