From: Dave Hansen <dave.hansen@intel.com>
To: Sultan Alsawaf <sultan@kerneltoast.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: Stop kswapd early when nothing's waiting for it to free pages
Date: Wed, 19 Feb 2020 11:13:21 -0800 [thread overview]
Message-ID: <dcd1cb4c-89dc-856b-ea1b-8d4930fec3eb@intel.com> (raw)
In-Reply-To: <20200219182522.1960-1-sultan@kerneltoast.com>
On 2/19/20 10:25 AM, Sultan Alsawaf wrote:
> Keeping kswapd running when all the failed allocations that invoked it
> are satisfied incurs a high overhead due to unnecessary page eviction
> and writeback, as well as spurious VM pressure events to various
> registered shrinkers. When kswapd doesn't need to work to make an
> allocation succeed anymore, stop it prematurely to save resources.
But kswapd isn't just to provide memory to waiters. It also serves to
get free memory back up to the high watermark. This seems like it might
result in more frequent allocation stalls and kswapd wakeups, which
consumes extra resources.
I guess I'd wonder what positive effects you have observed as a result
of this patch and whether you've gone looking for any negative effects.
next prev parent reply other threads:[~2020-02-19 19:13 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-19 18:25 [PATCH] mm: Stop kswapd early when nothing's waiting for it to free pages Sultan Alsawaf
2020-02-19 19:13 ` Dave Hansen [this message]
2020-02-19 19:40 ` Sultan Alsawaf
2020-02-19 20:05 ` Michal Hocko
2020-02-19 20:42 ` Sultan Alsawaf
2020-02-19 21:45 ` Mel Gorman
2020-02-19 22:42 ` Sultan Alsawaf
2020-02-20 10:19 ` Mel Gorman
2020-02-21 4:22 ` Sultan Alsawaf
2020-02-21 8:07 ` Michal Hocko
[not found] ` <20200221210824.GA3605@sultan-book.localdomain>
2020-02-21 21:24 ` Dave Hansen
2020-02-25 9:09 ` Michal Hocko
2020-02-25 17:12 ` Sultan Alsawaf
2020-02-26 9:05 ` Michal Hocko
2020-02-25 22:30 ` Shakeel Butt
2020-02-26 9:08 ` Michal Hocko
2020-02-26 17:00 ` Shakeel Butt
2020-02-26 17:41 ` Michal Hocko
2020-02-26 10:51 ` Hillf Danton
2020-02-26 17:04 ` Shakeel Butt
2020-02-27 1:48 ` Hillf Danton
2020-02-21 18:04 ` Shakeel Butt
2020-02-21 20:06 ` Sultan Alsawaf
2020-02-20 8:29 ` Michal Hocko
2020-02-19 19:26 ` Andrew Morton
2020-02-19 22:45 ` Sultan Alsawaf
2020-02-19 19:35 ` Michal Hocko
2020-02-21 4:30 ` [PATCH v2] " Sultan Alsawaf
2020-02-21 18:22 ` Ira Weiny
2020-02-21 20:00 ` Sultan Alsawaf
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