linux-kernel - Re: [PATCH 28/28] mm, page_alloc: Defer debugging checks of pages allocated from the PCP

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Message-ID: <20160427153121.GK2858@techsingularity.net>
Date:	Wed, 27 Apr 2016 16:31:21 +0100
From:	Mel Gorman <mgorman@...hsingularity.net>
To:	Vlastimil Babka <vbabka@...e.cz>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Jesper Dangaard Brouer <brouer@...hat.com>,
	Linux-MM <linux-mm@...ck.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 28/28] mm, page_alloc: Defer debugging checks of pages
 allocated from the PCP

On Wed, Apr 27, 2016 at 04:06:11PM +0200, Vlastimil Babka wrote:
> From afdefd87f2d8d07cba4bd2a2f3531dc8bb0b7a19 Mon Sep 17 00:00:00 2001
> From: Vlastimil Babka <vbabka@...e.cz>
> Date: Wed, 27 Apr 2016 15:47:29 +0200
> Subject: [PATCH] mm, page_alloc: uninline the bad page part of
>  check_new_page()
> 
> Bad pages should be rare so the code handling them doesn't need to be inline
> for performance reasons. Put it to separate function which returns void.
> This also assumes that the initial page_expected_state() result will match the
> result of the thorough check, i.e. the page doesn't become "good" in the
> meanwhile. This matches the same expectations already in place in
> free_pages_check().
> 
> !DEBUG_VM bloat-o-meter:
> 
> add/remove: 1/0 grow/shrink: 0/1 up/down: 134/-274 (-140)
> function                                     old     new   delta
> check_new_page_bad                             -     134    +134
> get_page_from_freelist                      3468    3194    -274
> 
> Signed-off-by: Vlastimil Babka <vbabka@...e.cz>

Acked-by: Mel Gorman <mgorman@...hsingularity.net>

Andrew, if you pick up v2 of of the follow-up series then can you also
add this patch on top if it's convenient please?

-- 
Mel Gorman
SUSE Labs