From: Sheng Yang <sheng@linux.intel.com>
To: kvm@vger.kernel.org
Cc: sudhir kumar <smalikphy@gmail.com>,
dlaor@redhat.com, Zhang Qian <zhq527725@gmail.com>
Subject: Re: How much physical memory can be used to run domains in a KVM machine?
Date: Mon, 20 Jul 2009 09:43:22 +0800 [thread overview]
Message-ID: <200907200943.23545.sheng@linux.intel.com> (raw)
In-Reply-To: <a50cf5ab0907170256i6ccb23c2t11d9428c15707ca5@mail.gmail.com>
On Friday 17 July 2009 17:56:49 sudhir kumar wrote:
> On Fri, Jul 17, 2009 at 12:47 PM, Dor Laor<dlaor@redhat.com> wrote:
> > On 07/17/2009 08:50 AM, Zhang Qian wrote:
> >> Hi,
> >>
> >> I have a KVM box which has 4GB physical memory totally, I'd like to
> >> know how much I can use to run my domains, and how much will be
> >> reserved by hypervisor(KVM) itself?
> >> Thanks!
> >
> > KVM and the Linux host use relatively low amount of memory.
> > Unlike other hypervisors you know, kvm does not reserve memory and also
> > is able to swap the guest memory, so you can even use more than 4G for
> > your
>
> Is that true? I think we can not allocate memory more than the
> physical RAM. Or does upstream kvm supports it? My kvm version is not
> that old but memory allocation failed for me when I tried to give the
> whole memory on my host to the guest.
It's not specific to KVM. QEmu use malloc()/mmap() to allocate memory for KVM,
which is controlled by Linux kernel memory overcommit policy. Linux kernel
didn't support memory overcommit by default. You can refer to
Document/vm/overcommit-accounting and other related document to enable it.
--
regards
Yang, Sheng
>
> > guest. (Just note swapping will be slow)
> >
> >> Regards,
> >> Qian
> >> --
> >> To unsubscribe from this list: send the line "unsubscribe kvm" in
> >> the body of a message to majordomo@vger.kernel.org
> >> More majordomo info at http://vger.kernel.org/majordomo-info.html
> >
> > --
> > To unsubscribe from this list: send the line "unsubscribe kvm" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
prev parent reply other threads:[~2009-07-20 1:43 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-07-17 5:50 How much physical memory can be used to run domains in a KVM machine? Zhang Qian
2009-07-17 7:17 ` Dor Laor
2009-07-17 9:56 ` sudhir kumar
2009-07-17 10:55 ` Amit Shah
2009-07-20 1:43 ` Sheng Yang [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=200907200943.23545.sheng@linux.intel.com \
--to=sheng@linux.intel.com \
--cc=dlaor@redhat.com \
--cc=kvm@vger.kernel.org \
--cc=smalikphy@gmail.com \
--cc=zhq527725@gmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.