Re: [PATCH] mm/mglru: wake up flushers when legacy cgroups run out of clean caches

[jingxiang zeng <jingxiangzeng.cas@gmail.com>]

I apologize for the half-dozen duplicate messages.  I was having a
difficult time configuring git to send email and didn't realize the
messages were actually getting delivered.

Ed

jingxiang zeng <jingxiangzeng.cas@gmail.com> 于2024年8月29日周四 16:36写道：
>
> Commit 14aa8b2d5c2e ("mm/mglru: don't sync disk for each aging cycle")
> removed the opportunity to wake up flushers during the MGLRU page
> reclamation process can lead to an increased likelihood of triggering
> OOM when encountering many dirty pages during reclamation on MGLRU.
>
> This leads to premature OOM if there are too many dirty pages in cgroup:
> Killed
>
> dd invoked oom-killer: gfp_mask=0x101cca(GFP_HIGHUSER_MOVABLE|__GFP_WRITE),
> order=0, oom_score_adj=0
>
> Call Trace:
>   <TASK>
>   dump_stack_lvl+0x5f/0x80
>   dump_stack+0x14/0x20
>   dump_header+0x46/0x1b0
>   oom_kill_process+0x104/0x220
>   out_of_memory+0x112/0x5a0
>   mem_cgroup_out_of_memory+0x13b/0x150
>   try_charge_memcg+0x44f/0x5c0
>   charge_memcg+0x34/0x50
>   __mem_cgroup_charge+0x31/0x90
>   filemap_add_folio+0x4b/0xf0
>   __filemap_get_folio+0x1a4/0x5b0
>   ? srso_return_thunk+0x5/0x5f
>   ? __block_commit_write+0x82/0xb0
>   ext4_da_write_begin+0xe5/0x270
>   generic_perform_write+0x134/0x2b0
>   ext4_buffered_write_iter+0x57/0xd0
>   ext4_file_write_iter+0x76/0x7d0
>   ? selinux_file_permission+0x119/0x150
>   ? srso_return_thunk+0x5/0x5f
>   ? srso_return_thunk+0x5/0x5f
>   vfs_write+0x30c/0x440
>   ksys_write+0x65/0xe0
>   __x64_sys_write+0x1e/0x30
>   x64_sys_call+0x11c2/0x1d50
>   do_syscall_64+0x47/0x110
>   entry_SYSCALL_64_after_hwframe+0x76/0x7e
>
>  memory: usage 308224kB, limit 308224kB, failcnt 2589
>  swap: usage 0kB, limit 9007199254740988kB, failcnt 0
>
>   ...
>   file_dirty 303247360
>   file_writeback 0
>   ...
>
> oom-kill:constraint=CONSTRAINT_MEMCG,nodemask=(null),cpuset=test,
> mems_allowed=0,oom_memcg=/test,task_memcg=/test,task=dd,pid=4404,uid=0
> Memory cgroup out of memory: Killed process 4404 (dd) total-vm:10512kB,
> anon-rss:1152kB, file-rss:1824kB, shmem-rss:0kB, UID:0 pgtables:76kB
> oom_score_adj:0
>
> Wake up flushers when legacy cgroups run out of clean caches.
>
> Fixes: 14aa8b2d5c2e ("mm/mglru: don't sync disk for each aging cycle")
> Signed-off-by: Zeng Jingxiang <linuszeng@tencent.com>
> Signed-off-by: kasong <kasong@tencent.com>