From: Stefan Hajnoczi <stefanha@gmail.com>
To: Peter Lieven <pl@dlh.net>
Cc: qemu-devel@nongnu.org, kvm@vger.kernel.org
Subject: Re: [Qemu-devel] linux guests and ksm performance
Date: Thu, 23 Feb 2012 16:42:54 +0000 [thread overview]
Message-ID: <CAJSP0QXPzBHopybzkncedQjzGiakbizs3nQMc0R7s2TNqwDOew@mail.gmail.com> (raw)
In-Reply-To: <1333613dbb15f2b736394d77e795223e.squirrel@ssl.dlh.net>
On Thu, Feb 23, 2012 at 3:40 PM, Peter Lieven <pl@dlh.net> wrote:
> However, in a virtual machine I have not observed the above slow down to
> that extend
> while the benefit of zero after free in a virtualisation environment is
> obvious:
>
> 1) zero pages can easily be merged by ksm or other technique.
> 2) zero (dup) pages are a lot faster to transfer in case of migration.
The other approach is a memory page "discard" mechanism - which
obviously requires more code changes than zeroing freed pages.
The advantage is that we don't take the brute-force and CPU intensive
approach of zeroing pages. It would be like a fine-grained ballooning
feature.
I hope someone will follow up saying this has already been done or
prototyped :).
Stefan
next prev parent reply other threads:[~2012-02-23 16:43 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-23 15:40 [Qemu-devel] linux guests and ksm performance Peter Lieven
2012-02-23 16:42 ` Stefan Hajnoczi [this message]
2012-02-23 18:39 ` Javier Guerra Giraldez
2012-02-23 19:08 ` peter.lieven@gmail.com
2012-02-24 6:41 ` Stefan Hajnoczi
2012-02-24 6:53 ` Stefan Hajnoczi
2012-02-24 7:23 ` Stefan Hajnoczi
2012-02-24 7:43 ` Peter Lieven
2012-02-28 11:45 ` Peter Lieven
[not found] ` <4F4CBE7C.8040304@dlh.net>
[not found] ` <CAJSP0QWj0fJT-P-yHKicz4mGyhW4RnWXgimNad07JYXew5qmZw@mail.gmail.com>
2012-02-28 12:16 ` Peter Lieven
2012-02-28 13:16 ` Avi Kivity
2012-02-28 13:20 ` Peter Lieven
2012-02-28 13:56 ` Avi Kivity
2012-02-24 7:04 ` Gleb Natapov
2012-02-28 13:14 ` Avi Kivity
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