From: Andrew Morton <akpm@linux-foundation.org>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andres Freund <andres@anarazel.de>,
Rik van Riel <riel@redhat.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
kernel-team@fb.com
Subject: Re: [PATCH 2/3] mm: filemap: only do access activations on reads
Date: Mon, 4 Apr 2016 14:22:33 -0700 [thread overview]
Message-ID: <20160404142233.cfdea284b8107768fb359efd@linux-foundation.org> (raw)
In-Reply-To: <1459790018-6630-3-git-send-email-hannes@cmpxchg.org>
On Mon, 4 Apr 2016 13:13:37 -0400 Johannes Weiner <hannes@cmpxchg.org> wrote:
> Andres Freund observed that his database workload is struggling with
> the transaction journal creating pressure on frequently read pages.
>
> Access patterns like transaction journals frequently write the same
> pages over and over, but in the majority of cases those pages are
> never read back. There are no caching benefits to be had for those
> pages, so activating them and having them put pressure on pages that
> do benefit from caching is a bad choice.
Read-after-write is a pretty common pattern: temporary files for
example. What are the opportunities for regressions here?
Did you consider providing userspace with a way to hint "this file is
probably write-then-not-read"?
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next prev parent reply other threads:[~2016-04-04 21:22 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-04 17:13 [PATCH 0/3] mm: support bigger cache workingsets and protect against writes Johannes Weiner
2016-04-04 17:13 ` [PATCH 1/3] mm: workingset: only do workingset activations on reads Johannes Weiner
2016-04-04 17:13 ` [PATCH 2/3] mm: filemap: only do access " Johannes Weiner
2016-04-04 21:22 ` Andrew Morton [this message]
2016-04-04 21:39 ` Rik van Riel
2016-04-04 21:55 ` Andrew Morton
2016-04-05 17:50 ` Johannes Weiner
2016-04-04 22:47 ` Johannes Weiner
2016-04-04 17:13 ` [PATCH 3/3] mm: vmscan: reduce size of inactive file list Johannes Weiner
2016-04-04 18:52 ` [PATCH 0/3] mm: support bigger cache workingsets and protect against writes Andres Freund
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