From: Minchan Kim <minchan@kernel.org>
To: Mel Gorman <mgorman@suse.de>
Cc: Hillf Danton <dhillf@gmail.com>,
LKML <linux-kernel@vger.kernel.org>,
Linux-MM <linux-mm@kvack.org>
Subject: Re: kswapd skips compaction if reclaim order drops to zero?
Date: Thu, 15 Aug 2013 22:41:39 +0900 [thread overview]
Message-ID: <20130815134139.GC8437@gmail.com> (raw)
In-Reply-To: <20130815104727.GT2296@suse.de>
Hey Mel,
On Thu, Aug 15, 2013 at 11:47:27AM +0100, Mel Gorman wrote:
> 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.
>
I am looking at mmotm-2013-08-07-16-55 but couldn't find cc->order
check right before compact_zone in __comact_pgdat.
Could you pinpoint code piece?
> --
> Mel Gorman
> SUSE Labs
>
> --
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--
Kind regards,
Minchan Kim
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next prev parent reply other threads:[~2013-08-15 13:41 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-15 10:02 kswapd skips compaction if reclaim order drops to zero? Hillf Danton
2013-08-15 10:47 ` Mel Gorman
2013-08-15 13:41 ` Minchan Kim [this message]
2013-08-15 13:56 ` Mel Gorman
2013-08-15 14:10 ` Minchan Kim
2013-08-15 15:39 ` [PATCH] mm: compaction: Do not compact pgdat for order-0 Mel Gorman
2013-08-16 4:37 ` Minchan Kim
2013-08-16 0:25 ` kswapd skips compaction if reclaim order drops to zero? Wanpeng Li
2013-08-16 0:25 ` Wanpeng Li
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