linux-kernel - Re: [PATCH v9] mm: Add memory allocation watchdog kernel thread.

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Message-Id: <201705281601.BBE81220.HFLOtSFFOJVQMO@I-love.SAKURA.ne.jp>
Date:   Sun, 28 May 2017 16:01:02 +0900
From:   Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
To:     akpm@...ux-foundation.org
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v9] mm: Add memory allocation watchdog kernel thread.

Tetsuo Handa wrote:
> Changes from v7 [11]:
> 
>   (1) Reflect review comments from Andrew Morton. (Convert "u8 type" to
>       "bool report", use CPUHP_PAGE_ALLOC_DEAD event and replace
>       for_each_possible_cpu() with for_each_online_cpu(), reuse existing
>       rcu_lock_break() and hung_timeout_jiffies() for now, update comments).
> 
> Changes from v8 [12]:
> 
>   (1) Check mempool_alloc() as well, for mempool_alloc() is a sort of
>       open-coded __GFP_NOFAIL allocation request where warn_alloc() cannot
>       detect stalls due to __GFP_NORETRY, and actually I found a case where
>       kswapd was unable to get memory for bio from mempool at
>       bio_alloc_bioset(GFP_NOFS) [13], and I believe there are similar bugs.

Andrew, I believe it is time to start testing at linux-next.

Nobody shows interests in detecting/analyzing OOM livelock but there are
still unsolved suspicious cases

  http://lkml.kernel.org/r/da13c3c7-b514-67b0-2eb9-6d6af277901b@wiesinger.com
  http://lkml.kernel.org/r/20170502141544.rufykv6blliqzqfd@merlins.org
  http://lkml.kernel.org/r/CAM_iQpWuPVGc2ky8M-9yukECtS+zKjiDasNymX7rMcBjBFyM_A@mail.gmail.com

where this patch might have given some clues if this patch were available.
There is no reason not to allow users to try this debugging aid.