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Date: Thu, 19 Apr 2018 13:36:34 -0700
From: Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [Bug 196157] New: 100+ times slower disk writes on
 4.x+/i386/16+RAM, compared to 3.x
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References: <bug-196157-27@https.bugzilla.kernel.org/>
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To: Alkis Georgopoulos <alkisg@gmail.com>
Cc: Michal Hocko <mhocko@kernel.org>, linux-mm@kvack.org, bugzilla-daemon@bugzilla.kernel.org, Mel Gorman <mgorman@techsingularity.net>, Johannes Weiner <hannes@cmpxchg.org>, reserv0@yahoo.com


(switched to email.  Please respond via emailed reply-to-all, not via the
bugzilla web interface).

https://bugzilla.kernel.org/show_bug.cgi?id=196157

People are still hurting from this.  It does seem a pretty major
regression for highmem machines.

I'm surprised that we aren't hearing about this from distros.  Maybe it
only affects a subset of highmem machines?

Anyway, can we please take another look at it?  Seems that we messed up
highmem dirty pagecache handling in the 4.2 timeframe.

Thanks.