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Date:   Wed, 19 Feb 2020 11:26:53 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Sultan Alsawaf <sultan@kerneltoast.com>
Cc:     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
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On Wed, 19 Feb 2020 10:25:22 -0800 Sultan Alsawaf <sultan@kerneltoast.com> 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.

Seems sensible.

Please fully describe the userspace-visible runtime effects of this
change?