From: Dave Chinner <david@fromorbit.com>
To: Mel Gorman <mgorman@techsingularity.net>
Cc: Michal Hocko <mhocko@kernel.org>,
linux-mm@kvack.org, linux-xfs@vger.kernel.org,
Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [PATCH] [Regression, v5.0] mm: boosted kswapd reclaim b0rks system cache balance
Date: Thu, 8 Aug 2019 10:30:25 +1000 [thread overview]
Message-ID: <20190808003025.GU7777@dread.disaster.area> (raw)
In-Reply-To: <20190807235534.GK2739@techsingularity.net>
On Thu, Aug 08, 2019 at 12:55:34AM +0100, Mel Gorman wrote:
> On Thu, Aug 08, 2019 at 08:08:17AM +1000, Dave Chinner wrote:
> > On Wed, Aug 07, 2019 at 04:03:16PM +0100, Mel Gorman wrote:
> > > On Wed, Aug 07, 2019 at 11:30:56AM +0200, Michal Hocko wrote:
> > > The boosting was not intended to target THP specifically -- it was meant
> > > to help recover early from any fragmentation-related event for any user
> > > that might need it. Hence, it's not tied to THP but even with THP
> > > disabled, the boosting will still take effect.
> > >
> > > One band-aid would be to disable watermark boosting entirely when THP is
> > > disabled but that feels wrong. However, I would be interested in hearing
> > > if sysctl vm.watermark_boost_factor=0 has the same effect as your patch.
> >
> > <runs test>
> >
> > Ok, it still runs it out of page cache, but it doesn't drive page
> > cache reclaim as hard once there's none left. The IO patterns are
> > less peaky, context switch rates are increased from ~3k/s to 15k/s
> > but remain pretty steady.
> >
> > Test ran 5s faster and file rate improved by ~2%. So it's better
> > once the page cache is largerly fully reclaimed, but it doesn't
> > prevent the page cache from being reclaimed instead of inodes....
> >
>
> Ok. Ideally you would also confirm the patch itself works as you want.
> It *should* but an actual confirmation would be nice.
Yup, I'll get to that later today.
Cheers,
Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2019-08-08 0:31 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-07 9:18 [PATCH] [Regression, v5.0] mm: boosted kswapd reclaim b0rks system cache balance Dave Chinner
2019-08-07 9:30 ` Michal Hocko
2019-08-07 15:03 ` Mel Gorman
2019-08-07 20:56 ` Mel Gorman
2019-08-07 22:32 ` Dave Chinner
2019-08-07 23:48 ` Mel Gorman
2019-08-08 0:26 ` Dave Chinner
2019-08-08 15:36 ` Christoph Hellwig
2019-08-08 17:04 ` Mel Gorman
2019-08-07 22:08 ` Dave Chinner
2019-08-07 22:33 ` Dave Chinner
2019-08-07 23:55 ` Mel Gorman
2019-08-08 0:30 ` Dave Chinner [this message]
2019-08-08 5:51 ` Dave Chinner
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