linux-kernel - Re: [PATCH v2 00/10] try to reduce fragmenting fallbacks

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Message-ID: <20170223160119.crigcfmfzphxirh6@techsingularity.net>
Date:   Thu, 23 Feb 2017 16:01:19 +0000
From:   Mel Gorman <mgorman@...hsingularity.net>
To:     Vlastimil Babka <vbabka@...e.cz>
Cc:     linux-mm@...ck.org, Johannes Weiner <hannes@...xchg.org>,
        Joonsoo Kim <iamjoonsoo.kim@....com>,
        David Rientjes <rientjes@...gle.com>,
        linux-kernel@...r.kernel.org, kernel-team@...com
Subject: Re: [PATCH v2 00/10] try to reduce fragmenting fallbacks

On Mon, Feb 20, 2017 at 01:30:33PM +0100, Vlastimil Babka wrote:
> On 02/13/2017 12:07 PM, Mel Gorman wrote:
> > On Fri, Feb 10, 2017 at 06:23:33PM +0100, Vlastimil Babka wrote:
> > 
> > By and large, I like the series, particularly patches 7 and 8. I cannot
> > make up my mind about the RFC patches 9 and 10 yet. Conceptually they
> > seem sound but they are much more far reaching than the rest of the
> > series.
> > 
> > It would be nice if patches 1-8 could be treated in isolation with data
> > on the number of extfrag events triggered, time spent in compaction and
> > the success rate. Patches 9 and 10 are tricy enough that they would need
> > data per patch where as patches 1-8 should be ok with data gathered for
> > the whole series.
>  
> Ok let's try again with a fresh subthread after fixing automation and
> postprocessing...
> 
> <SNIP>
> 
> To sum up, patches 1-8 look OK to me. Patch 9 looks also very promising, but
> there's danger of increased allocation latencies due to the forced compaction.
> Patch 10 has either implementation bugs or there's some unforeseen consequence
> of its design.
> 

I don't have anything useful to add other than the figures for patches
1-8 look good and the fact that fragmenting events that misplace unmovable
allocations is welcome.

-- 
Mel Gorman
SUSE Labs