From: James Bottomley <James.Bottomley@HansenPartnership.com>
To: Dan Magenheimer <dan.magenheimer@oracle.com>
Cc: John Stoffel <john@stoffel.org>,
Johannes Weiner <jweiner@redhat.com>,
Pekka Enberg <penberg@kernel.org>,
Cyclonus J <cyclonusj@gmail.com>,
Sasha Levin <levinsasha928@gmail.com>,
Christoph Hellwig <hch@infradead.org>,
David Rientjes <rientjes@google.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Konrad Wilk <konrad.wilk@oracle.com>,
Jeremy Fitzhardinge <jeremy@goop.org>,
Seth Jennings <sjenning@linux.vnet.ibm.com>,
ngupta@vflare.org, Chris Mason <chris.mason@oracle.com>,
JBeulich@novell.com, Dave Hansen <dave@linux.vnet.ibm.com>,
Jonathan Corbet <corbet@lwn.net>
Subject: RE: [GIT PULL] mm: frontswap (for 3.2 window)
Date: Mon, 31 Oct 2011 12:12:47 +0400 [thread overview]
Message-ID: <1320048767.8283.13.camel@dabdike> (raw)
In-Reply-To: <3982e04f-8607-4f0a-b855-2e7f31aaa6f7@default>
On Fri, 2011-10-28 at 13:19 -0700, Dan Magenheimer wrote:
> For those who "hack on the VM", I can't imagine why the handful
> of lines in the swap subsystem, which is probably the most stable
> and barely touched subsystem in Linux or any OS on the planet,
> is going to be a burden or much of a cost.
Saying things like this doesn't encourage anyone to trust you. The
whole of the MM is a complex, highly interacting system. The recent
issues we've had with kswapd and the shrinker code gives a nice
demonstration of this ... and that was caused by well tested code
updates. You can't hand wave away the need for benchmarks and
performance tests.
You have also answered all questions about inactive cost by saying "the
code has zero cost when it's compiled out" This also is a non starter.
For the few use cases it has, this code has to be compiled in. I
suspect even Oracle isn't going to ship separate frontswap and
non-frontswap kernels in its distro. So you have to quantify what the
performance impact is when this code is compiled in but not used.
Please do so.
James
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next prev parent reply other threads:[~2011-10-31 8:12 UTC|newest]
Thread overview: 87+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-27 18:52 [GIT PULL] mm: frontswap (for 3.2 window) Dan Magenheimer
[not found] ` <alpine.DEB.2.00.1110271318220.7639@chino.kir.corp.google.com20111027211157.GA1199@infradead.org>
2011-10-27 19:30 ` Kurt Hackel
2011-10-27 20:18 ` David Rientjes
2011-10-27 21:11 ` Christoph Hellwig
2011-10-27 21:49 ` Dan Magenheimer
2011-10-27 21:52 ` Christoph Hellwig
2011-10-27 22:21 ` Dan Magenheimer
2011-10-28 7:12 ` Sasha Levin
[not found] ` <CAOzbF4fnD=CGR-nizZoBxmFSuAjFC3uAHf3wDj5RLneJvJhrOQ@mail.gmail.comCAOJsxLGOTw7rtFnqeHvzFxifA0QgPVDHZzrEo=-uB2Gkrvp=JQ@mail.gmail.com>
[not found] ` <552d2067-474d-4aef-a9a4-89e5fd8ef84f@default20111031181651.GF3466@redhat.com>
[not found] ` <60592afd-97aa-4eaf-b86b-f6695d31c7f1@default20111031223717.GI3466@redhat.com>
[not found] ` <1b2e4f74-7058-4712-85a7-84198723e3ee@default20111101012017.GJ3466@redhat.com>
[not found] ` <6a9db6d9-6f13-4855-b026-ba668c29ddfa@default20111101180702.GL3466@redhat.com>
[not found] ` <b8a0ca71-a31b-488a-9a92-2502d4a6e9bf@default20111102013122.GA18879@redhat.com>
2011-10-28 7:30 ` Cyclonus J
2011-10-28 14:26 ` Pekka Enberg
2011-10-28 15:21 ` Dan Magenheimer
[not found] ` <CAOJsxLEE-qf9me1SAZLFiEVhHVnDh7BDrSx1+abe9R4mfkhD=g@mail.gmail.com20111028163053.GC1319@redhat.com>
2011-10-28 15:36 ` Pekka Enberg
2011-10-28 16:30 ` Johannes Weiner
2011-10-28 17:01 ` Pekka Enberg
2011-10-28 17:07 ` Dan Magenheimer
2011-10-28 18:28 ` John Stoffel
2011-10-28 20:19 ` Dan Magenheimer
2011-10-28 20:52 ` John Stoffel
2011-10-30 19:18 ` Dan Magenheimer
2011-10-30 20:06 ` Dave Hansen
2011-10-30 21:50 ` Dan Magenheimer
2011-11-02 19:45 ` Rik van Riel
2011-11-02 20:45 ` Dan Magenheimer
2011-11-06 22:32 ` Valdis.Kletnieks
2011-11-08 12:15 ` Ed Tomlinson
2011-10-31 8:12 ` James Bottomley [this message]
2011-10-31 15:39 ` Dan Magenheimer
2011-11-01 10:13 ` James Bottomley
2011-11-01 18:10 ` Dan Magenheimer
2011-11-01 18:48 ` Dave Hansen
2011-11-01 21:32 ` Dan Magenheimer
2011-11-02 7:44 ` James Bottomley
2011-11-02 19:39 ` Dan Magenheimer
2011-10-31 18:44 ` Andrea Arcangeli
2011-10-30 21:47 ` Johannes Weiner
2011-10-30 23:19 ` Dan Magenheimer
2011-10-31 18:34 ` Andrea Arcangeli
2011-10-31 21:45 ` Dan Magenheimer
2011-10-28 16:37 ` Dan Magenheimer
2011-10-28 16:59 ` Pekka Enberg
2011-10-28 17:20 ` Dan Magenheimer
2011-10-31 18:16 ` Andrea Arcangeli
2011-10-31 20:58 ` Dan Magenheimer
2011-10-31 22:37 ` Andrea Arcangeli
2011-10-31 23:36 ` Dan Magenheimer
2011-11-01 1:20 ` Andrea Arcangeli
2011-11-01 16:41 ` Dan Magenheimer
2011-11-01 18:07 ` Andrea Arcangeli
2011-11-01 21:00 ` Dan Magenheimer
2011-11-02 1:31 ` Andrea Arcangeli
2011-11-02 19:06 ` Dan Magenheimer
2011-11-03 0:32 ` Andrea Arcangeli
2011-11-03 22:29 ` Dan Magenheimer
2011-11-02 20:51 ` Rik van Riel
2011-11-02 21:14 ` Dan Magenheimer
2011-11-15 16:29 ` Rik van Riel
2011-11-15 17:33 ` Jeremy Fitzhardinge
2011-11-16 14:49 ` Konrad Rzeszutek Wilk
2011-11-01 10:16 ` James Bottomley
2011-11-01 18:21 ` Dan Magenheimer
2011-11-02 8:14 ` James Bottomley
2011-11-02 20:08 ` Dan Magenheimer
2011-11-03 10:30 ` Theodore Tso
2011-11-03 14:59 ` Dan Magenheimer
2011-11-02 15:44 ` Avi Kivity
2011-11-02 16:02 ` Andrea Arcangeli
2011-11-02 16:13 ` Avi Kivity
2011-11-02 20:27 ` Dan Magenheimer
2011-11-02 20:19 ` Dan Magenheimer
2011-10-27 21:44 ` Avi Miller
2011-10-27 22:33 ` Brian King
2011-10-28 5:17 ` Nitin Gupta
2011-10-29 13:43 ` Ed Tomlinson
2011-10-31 8:13 ` KAMEZAWA Hiroyuki
2011-10-31 16:38 ` Dan Magenheimer
2011-11-01 0:50 ` KAMEZAWA Hiroyuki
2011-11-01 15:25 ` Dan Magenheimer
2011-11-01 21:43 ` Andrew Morton
2011-11-01 22:25 ` Dan Magenheimer
2011-11-02 21:03 ` Rik van Riel
2011-11-02 21:42 ` Dan Magenheimer
2011-11-02 1:14 ` KAMEZAWA Hiroyuki
2011-11-02 15:12 ` Dan Magenheimer
2011-11-04 4:19 ` KAMEZAWA Hiroyuki
2011-11-03 16:49 ` Jan Beulich
2011-11-04 0:54 ` Andrew Morton
2011-11-04 8:49 ` Jan Beulich
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