linux-kernel - Re: [PATCH 2/8] mm, page_alloc: set alloc

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Message-ID: <alpine.DEB.2.10.1607191527400.19940@chino.kir.corp.google.com>
Date:	Tue, 19 Jul 2016 15:28:16 -0700 (PDT)
From:	David Rientjes <rientjes@...gle.com>
To:	Vlastimil Babka <vbabka@...e.cz>
cc:	Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org, Michal Hocko <mhocko@...nel.org>,
	Mel Gorman <mgorman@...hsingularity.net>,
	Joonsoo Kim <iamjoonsoo.kim@....com>,
	Rik van Riel <riel@...hat.com>
Subject: Re: [PATCH 2/8] mm, page_alloc: set alloc_flags only once in
 slowpath

On Mon, 18 Jul 2016, Vlastimil Babka wrote:

> In __alloc_pages_slowpath(), alloc_flags doesn't change after it's initialized,
> so move the initialization above the retry: label. Also make the comment above
> the initialization more descriptive.
> 
> The only exception in the alloc_flags being constant is ALLOC_NO_WATERMARKS,
> which may change due to TIF_MEMDIE being set on the allocating thread. We can
> fix this, and make the code simpler and a bit more effective at the same time,
> by moving the part that determines ALLOC_NO_WATERMARKS from
> gfp_to_alloc_flags() to gfp_pfmemalloc_allowed(). This means we don't have to
> mask out ALLOC_NO_WATERMARKS in numerous places in __alloc_pages_slowpath()
> anymore. The only two tests for the flag can instead call
> gfp_pfmemalloc_allowed().
> 
> Signed-off-by: Vlastimil Babka <vbabka@...e.cz>

Acked-by: David Rientjes <rientjes@...gle.com>

Looks good, although maybe a new name for gfp_pfmemalloc_allowed() would 
be in order.