From: Rik van Riel <riel@redhat.com>
To: Mel Gorman <mgorman@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
akpm@linux-foundation.org, Josh Boyer <jwboyer@redhat.com>,
aarcange@redhat.com, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] mm: Abort reclaim/compaction if compaction can proceed
Date: Fri, 07 Oct 2011 18:42:42 -0400 [thread overview]
Message-ID: <4E8F8062.2080105@redhat.com> (raw)
In-Reply-To: <20111007202417.GD6418@suse.de>
On 10/07/2011 04:24 PM, Mel Gorman wrote:
> On Fri, Oct 07, 2011 at 04:07:06PM -0400, Rik van Riel wrote:
>> On 10/07/2011 11:17 AM, Mel Gorman wrote:
>>> If compaction can proceed, shrink_zones() stops doing any work but
>>> the callers still shrink_slab(), raises the priority and potentially
>>> sleeps. This patch aborts direct reclaim/compaction entirely if
>>> compaction can proceed.
>>>
>>> Signed-off-by: Mel Gorman<mgorman@suse.de>
>>
>> This patch makes sense to me, but I have not tested it like
>> the first one.
>>
>
> Do if you can.
I'll probably build a kernel with your patch in it on
Sunday - I'll be walking across a mountain tomorrow :)
> It's marginal and could be confirmation bias on my part. Basically,
> there is noise when this path is being exercised but there were fewer
> slabs scanned. However, I don't know what the variances are and
> whether the reduction was within the noise or not but it makes sense
> that it would scan less. If I profiled carefully, I might be able
> to show that a few additional cycles are spent raising the priority
> but it would be marginal.
This seems clear enough.
> While patch 1 is very clear, patch 2 depends on reviewers deciding it
> "makes sense".
>
>> Having said that, I'm pretty sure the patch is ok :)
>>
>
> Care to ack?
Sure.
Acked-by: Rik van Riel <riel@redhat.com>
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next prev parent reply other threads:[~2011-10-07 22:42 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-07 15:17 [PATCH 0/2] Avoid excessive reclaim due to THP Mel Gorman
2011-10-07 15:17 ` [PATCH 1/2] mm: vmscan: Limit direct reclaim for higher order allocations Mel Gorman
2011-10-07 19:32 ` Rik van Riel
2011-10-07 20:18 ` Mel Gorman
2011-10-09 8:02 ` Minchan Kim
2011-10-07 15:17 ` [PATCH 2/2] mm: Abort reclaim/compaction if compaction can proceed Mel Gorman
2011-10-07 20:07 ` Rik van Riel
2011-10-07 20:24 ` Mel Gorman
2011-10-07 22:42 ` Rik van Riel [this message]
2011-10-09 8:04 ` Minchan Kim
2011-10-12 14:57 ` Johannes Weiner
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