From: Mel Gorman <mgorman@suse.de>
To: Hillf Danton <dhillf@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>,
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 11:47:27 +0100 [thread overview]
Message-ID: <20130815104727.GT2296@suse.de> (raw)
In-Reply-To: <CAJd=RBBF2h_tRpbTV6OkxQOfkvKt=ebn_PbE8+r7JxAuaFZxFQ@mail.gmail.com>
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
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WARNING: multiple messages have this Message-ID (diff)
From: Mel Gorman <mgorman@suse.de>
To: Hillf Danton <dhillf@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>,
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 11:47:27 +0100 [thread overview]
Message-ID: <20130815104727.GT2296@suse.de> (raw)
In-Reply-To: <CAJd=RBBF2h_tRpbTV6OkxQOfkvKt=ebn_PbE8+r7JxAuaFZxFQ@mail.gmail.com>
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
next prev parent reply other threads:[~2013-08-15 10:47 UTC|newest]
Thread overview: 16+ 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 10:02 ` Hillf Danton
2013-08-15 10:47 ` Mel Gorman [this message]
2013-08-15 10:47 ` Mel Gorman
2013-08-15 13:41 ` Minchan Kim
2013-08-15 13:41 ` Minchan Kim
2013-08-15 13:56 ` Mel Gorman
2013-08-15 13:56 ` Mel Gorman
2013-08-15 14:10 ` Minchan Kim
2013-08-15 14:10 ` Minchan Kim
2013-08-15 15:39 ` [PATCH] mm: compaction: Do not compact pgdat for order-0 Mel Gorman
2013-08-15 15:39 ` Mel Gorman
2013-08-16 4:37 ` Minchan Kim
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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