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From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
To: Kevin Wolf <kwolf@redhat.com>
Cc: Pankaj Gupta <pagupta@redhat.com>,
	qemu-block@nongnu.org, qemu-devel@nongnu.org, mreitz@redhat.com,
	quintela@redhat.com
Subject: Re: [Qemu-devel] [PATCH] block, migration: Use qemu_madvise inplace of madvise
Date: Fri, 17 Feb 2017 09:48:33 +0000	[thread overview]
Message-ID: <20170217094830.GA4941@work-vm> (raw)
In-Reply-To: <20170217084951.GA5338@noname.redhat.com>

* Kevin Wolf (kwolf@redhat.com) wrote:
> Am 17.02.2017 um 09:06 hat Pankaj Gupta geschrieben:
> >  To maintain consistency at all the places use qemu_madvise wrapper
> >  inplace of madvise call.
> > 
> > Signed-off-by: Pankaj Gupta <pagupta@redhat.com>
> 
> Reviewed-by: Kevin Wolf <kwolf@redhat.com>
> 
> Juan/Dave, if one of you can give an Acked-by, I can take this through
> my tree.

NACK

That's wrong; qemu_madvise can end up going through posix_madvise and
using POSIX_MADV_DONTNEED, it has different semantics to the madvise(MADV_DONTNEED)
and we need the semantics of madvise - i.e. it's guaranteed to throw
away the pages, where as posix_madvise *may* throw away the pages if
the kernel feels like it.

Dave

> Kevin
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK

  reply	other threads:[~2017-02-17  9:48 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-17  8:06 [Qemu-devel] [PATCH] block, migration: Use qemu_madvise inplace of madvise Pankaj Gupta
2017-02-17  8:49 ` Kevin Wolf
2017-02-17  9:48   ` Dr. David Alan Gilbert [this message]
2017-02-17 10:06 ` [Qemu-devel] [Qemu-block] " Alberto Garcia
2017-02-17 11:30   ` Pankaj Gupta
2017-02-17 11:36     ` Dr. David Alan Gilbert
2017-02-17 12:30       ` Pankaj Gupta
2017-02-17 12:49         ` Alberto Garcia
2017-02-17 12:31     ` Alberto Garcia

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