From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: Rusty Russell <rusty@ozlabs.au.ibm.com>,
Hollis Blanchard <hollisb@us.ibm.com>,
kvm-devel <kvm@vger.kernel.org>
Subject: Re: [Qemu-devel] [5874] Add virtio-balloon support
Date: Fri, 5 Dec 2008 14:14:37 +0000 [thread overview]
Message-ID: <200812051414.38406.paul@codesourcery.com> (raw)
In-Reply-To: <49385B02.9010206@codemonkey.ws>
On Thursday 04 December 2008, Anthony Liguori wrote:
> Hollis Blanchard wrote:
> > On Thu, 2008-12-04 at 20:33 +0000, Anthony Liguori wrote:
> >> +static void balloon_page(void *addr, int deflate)
> >> +{
> >> +#if defined(__linux__)
> >> + if (!kvm_enabled() || kvm_has_sync_mmu())
> >> + madvise(addr, TARGET_PAGE_SIZE,
> >> + deflate ? MADV_WILLNEED : MADV_DONTNEED);
> >> +#endif
> >> +}
> >
> > Hmm, I just noticed this... we need to use VIRTIO_BALLOON_PFN_SHIFT like
> > Rusty did on the kernel side.
> >
> > However, in general I'm not sure how this is supposed to work. Isn't it
> > true that madvise() is a no-op if 0 < length < getpagesize()? If so, how
> > should the guest know the chunk size needed on the host?
>
> We need to pass multiple of TARGET_PAGE_SIZE to madvise()
You mean HOST_PAGE_SIZE?
My linux manpage says that the address must be page aligned.
Paul
next prev parent reply other threads:[~2008-12-05 14:15 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-04 20:33 [Qemu-devel] [5874] Add virtio-balloon support Anthony Liguori
2008-12-04 21:34 ` Hollis Blanchard
2008-12-04 22:34 ` Anthony Liguori
2008-12-05 14:14 ` Paul Brook [this message]
2008-12-05 14:21 ` Anthony Liguori
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