linux-kernel - Re: [PATCH 09/11] mm, compaction: Abstract compaction feedback to helpers

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20160411153357.GM23157@dhcp22.suse.cz>
Date:	Mon, 11 Apr 2016 17:33:58 +0200
From:	Michal Hocko <mhocko@...nel.org>
To:	Vlastimil Babka <vbabka@...e.cz>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Johannes Weiner <hannes@...xchg.org>,
	Mel Gorman <mgorman@...e.de>,
	David Rientjes <rientjes@...gle.com>,
	Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
	Joonsoo Kim <js1304@...il.com>,
	Hillf Danton <hillf.zj@...baba-inc.com>, linux-mm@...ck.org,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 09/11] mm, compaction: Abstract compaction feedback to
 helpers

On Mon 11-04-16 17:14:10, Michal Hocko wrote:
> On Mon 11-04-16 16:39:21, Vlastimil Babka wrote:
> > On 04/05/2016 01:25 PM, Michal Hocko wrote:
[...]
> > >+	/*
> > >+	 * Checks for THP-specific high-order allocations and back off
> > >+	 * if the the compaction backed off
> > >+	 */
> > >+	if (is_thp_gfp_mask(gfp_mask) && compaction_withdrawn(compact_result))
> > >+		goto nopage;
> > 
> > The change of semantics for THP is not trivial here and should at least be
> > discussed in changelog. CONTENDED and DEFERRED is only subset of
> > compaction_withdrawn() as seen above.
> 
> True. My main motivation was to get rid of the compaction specific code
> from the allocator path as much as possible. I can drop the above hunk

I was thinking about this some more and will drop the hunk. I would
rather have this patch without side effects as much as possible. A
follow up patch can get rid of the specific checks and use a simpler
ones. I will post -fix patch to Andrew.
-- 
Michal Hocko
SUSE Labs