mm/cgroup/reclaim: fix dirty pages throttling on cgroup v1
authorAneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Fri, 18 Nov 2022 07:06:03 +0000 (12:36 +0530)
committerAndrew Morton <akpm@linux-foundation.org>
Wed, 23 Nov 2022 02:50:45 +0000 (18:50 -0800)
commit81a70c21d9170de67a45843bdd627f4cce9c4215
tree21b0e60c2d5eb5b04a3cd9ff696470cf06537b13
parentea4452de2ae987342fadbdd2c044034e6480daad
mm/cgroup/reclaim: fix dirty pages throttling on cgroup v1

balance_dirty_pages doesn't do the required dirty throttling on cgroupv1.
See commit 9badce000e2c ("cgroup, writeback: don't enable cgroup writeback
on traditional hierarchies").  Instead, the kernel depends on writeback
throttling in shrink_folio_list to achieve the same goal.  With large
memory systems, the flusher may not be able to writeback quickly enough
such that we will start finding pages in the shrink_folio_list already in
writeback.  Hence for cgroupv1 let's do a reclaim throttle after waking up
the flusher.

The below test which used to fail on a 256GB system completes till the the
file system is full with this change.

root@lp2:/sys/fs/cgroup/memory# mkdir test
root@lp2:/sys/fs/cgroup/memory# cd test/
root@lp2:/sys/fs/cgroup/memory/test# echo 120M > memory.limit_in_bytes
root@lp2:/sys/fs/cgroup/memory/test# echo $$ > tasks
root@lp2:/sys/fs/cgroup/memory/test# dd if=/dev/zero of=/home/kvaneesh/test bs=1M
Killed

Link: https://lkml.kernel.org/r/20221118070603.84081-1-aneesh.kumar@linux.ibm.com
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: zefan li <lizefan.x@bytedance.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mm/vmscan.c