From: Avi Kivity <avi@redhat.com>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>,
Dan Magenheimer <dan.magenheimer@oracle.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: Wed, 02 Nov 2011 18:13:11 +0200 [thread overview]
Message-ID: <4EB16C17.40906@redhat.com> (raw)
In-Reply-To: <20111102160201.GB18879@redhat.com>
On 11/02/2011 06:02 PM, Andrea Arcangeli wrote:
> Hi Avi,
>
> On Wed, Nov 02, 2011 at 05:44:50PM +0200, Avi Kivity wrote:
> > If you look at cleancache, then it addresses this concern - it extends
> > pagecache through host memory. When dropping a page from the tail of
> > the LRU it first goes into tmem, and when reading in a page from disk
> > you first try to read it from tmem. However in many workloads,
> > cleancache is actually detrimental. If you have a lot of cache misses,
> > then every one of them causes a pointless vmexit; considering that
> > servers today can chew hundreds of megabytes per second, this adds up.
> > On the other side, if you have a use-once workload, then every page that
> > falls of the tail of the LRU causes a vmexit and a pointless page copy.
>
> I also think it's bad design for Virt usage, but hey, without this
> they can't even run with cache=writeback/writethrough and they're
> forced to cache=off, and then they claim specvirt is marketing, so for
> Xen it's better than nothing I guess.
Surely Xen can use the pagecache, it uses Linux for I/O just like kvm.
> I'm trying right now to evaluate it as a pure zcache host side
> optimization.
zcache style usage is fine. It's purely internal so no ABI constraints,
and no hypercalls either. It's still synchronous though so RAMster like
approaches will not work well.
<snip>
--
error compiling committee.c: too many arguments to function
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next prev parent reply other threads:[~2011-11-02 16:13 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
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 [this message]
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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