Hi, Hugh.
On Wednesday, 30 December 2009 18:14:30 +0000,
Hugh Dickins wrote:
> On Sun, 27 Dec 2009, Rik van Riel wrote:
> > On 12/27/2009 12:12 PM, Avi Kivity wrote:
> > > On 12/27/2009 06:45 PM, Rik van Riel wrote:
> > > >
> > > > > If so, it doesn't copy stable@xxxxxxxxxxx Is it queued for -stable?
> > > >
> > > > I do not believe that it is queued for -stable.
> > > >
> > > > Do performance fixes fit with -stable policy?
> > >
> > > If it is a serious regression, I believe it fits.
> >
> > It's probably been there since 2.6.28, though it might have been
> > introduced later with a cleanup patch. It seems to go back at
> > least as far as March...
> It does look as if it would have got worse in 2.6.31 and 2.6.32
> - though I am reluctant to predict how these scans work out in
> practice from just glancing at the code!
>
> I agree with Avi (or with Avi's implication), that it would be
> worth sending the fix to -stable - but it would be nice to hear
> if the patch (inline below) actually does fix Daniel's problem.
> It applies and builds correctly on 2.6.31.9 and 2.6.32.3.
>
> We have certainly sent much more specialized performance fixes
> to -stable (I'm thinking of Lee's anon_vma locking), and I see
> this as more of a straightforward bugfix anyway - people get
> worried by going into swap without understanding why.
>
> I forget which patch of mine Avi was thinking of,
> but I'm pretty sure Rik's will prove much the more relevant.
I shutdown the virtual machines yesterday and I boot them again and the
swap usage did not exceed the 9 MB / 486 MB with /proc/sys/vm/swappiness
set to 0. Now I tried restarting the host with the same running VM and,
at the moment, the use of swap is zero with /proc/sys/vm/swappiness by
default (60).
root@ubuntu:~# free
total used free shared buffers cached
Mem: 4060340 2299556 1760784 0 837668 133292
-/+ buffers/cache: 1328596 2731744
Swap: 497972 0 497972
What tests would be recommendable to make to reproduce the problem?
You say that the patch applies and builds correctly on 2.6.31.9 and
2.6.32.3. I would like to test it with 2.6.32.3, but I didn't find the
source code of it in [1]. It would have to be in another path?
Thanks for your reply and the patch.
Regards,
Daniel
[1] http://www.kernel.org/pub/linux/kernel/v2.6/
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