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From: Andrea Arcangeli <andrea@qumranet.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Avi Kivity <avi@qumranet.com>, kvm-devel <kvm@vger.kernel.org>
Subject: Re: KVM: MMU: rmap_write_protect() hugepage iteration bug
Date: Sun, 8 Jun 2008 22:30:37 +0200	[thread overview]
Message-ID: <20080608203037.GB9921@duo.random> (raw)
In-Reply-To: <20080608195215.GA5824@dmt.cnet>

On Sun, Jun 08, 2008 at 04:52:15PM -0300, Marcelo Tosatti wrote:
> We do. The case is were you have two entries in the array. rmap_remove
> will first remove the entry at index 0, and move the entry at index 1 to
> 0.
> 
> Then we call "rmap_next()" with a non-NULL spte, which will skip the
> only remaining entry at index 0. IOW rmap_next() requires the spte
> argument to be NULL if the array has one valid entry.

How exactly we could call rmap_next with not-NULL spte after any
rmap_remove with your last patch applied?

> > chains are fairly long. To be sure you could try to profile it and see
> > if rmap_write_protect goes up in the opreport.
> 
> Will do.

Cool, thanks!

  reply	other threads:[~2008-06-08 20:30 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-06-08  0:27 KVM: MMU: rmap_write_protect() hugepage iteration bug Marcelo Tosatti
2008-06-08  1:54 ` Andrea Arcangeli
2008-06-08  4:48   ` Marcelo Tosatti
2008-06-08  7:30     ` Avi Kivity
2008-06-08  8:03       ` Avi Kivity
2008-06-08  8:04         ` Avi Kivity
2008-06-08 18:31     ` Andrea Arcangeli
2008-06-08 19:52       ` Marcelo Tosatti
2008-06-08 20:30         ` Andrea Arcangeli [this message]
2008-06-09  0:20           ` Marcelo Tosatti
2008-06-09  0:55             ` Andrea Arcangeli

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