Re: [REPOST] [PATCH 1/2] mm: Fix race between setting TIF_MEMDIE and __alloc_pages_high_priority().

[Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>]

Michal Hocko wrote:
> The comment above the check is misleading but now you are allowing to
> fail all ALLOC_NO_WATERMARKS (without __GFP_NOFAIL) allocations before
> entering the direct reclaim and compaction. This seems incorrect. What
> about __GFP_MEMALLOC requests?

So, you want __GPP_MEMALLOC to retry forever unless TIF_MEMDIE is set, don't
you?

> I think the check for TIF_MEMDIE makes more sense here.

Since we already failed to allocate from memory reserves, I don't know if
direct reclaim and compaction can work as expected under such situation.
Maybe the OOM killer is invoked, but I worry that the OOM victim gets stuck
because we already failed to allocate from memory reserves. Unless next OOM
victims are chosen via timeout, I think that this can be one of triggers
that lead to silent hangup... (Just my suspect. I can't prove it because I
can't go to in front of customers' servers and check SysRq.)

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