linux-kernel - Re: kswapd skips compaction if reclaim order drops to zero?

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: <20130815104727.GT2296@suse.de>
Date:	Thu, 15 Aug 2013 11:47:27 +0100
From:	Mel Gorman <mgorman@...e.de>
To:	Hillf Danton <dhillf@...il.com>
Cc:	Minchan Kim <minchan@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Linux-MM <linux-mm@...ck.org>
Subject: Re: kswapd skips compaction if reclaim order drops to zero?

On Thu, Aug 15, 2013 at 06:02:53PM +0800, Hillf Danton wrote:
> If the allocation order is not high, direct compaction does nothing.
> Can we skip compaction here if order drops to zero?
> 

If the allocation order is not high then

pgdat_needs_compaction == (order > 0) == false == no calling compact_pdatt

In the case where order is reset to 0 due to fragmentation then it does
call compact_pgdat but it does no work due to the cc->order check in
__compact_pgdat.

-- 
Mel Gorman
SUSE Labs
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/