Re: 2.6.39-rc4+: Kernel leaking memory during FS scanning, regression?

[Sedat Dilek <sedat.dilek@googlemail.com>]

On Fri, Apr 29, 2011 at 10:14 PM, Bruno Prémont
<bonbons@linux-vserver.org> wrote:
> On Fri, 29 April 2011 Thomas Gleixner wrote:
>> On Fri, 29 Apr 2011, Bruno Prémont wrote:
>> > On Fri, 29 April 2011 Thomas Gleixner wrote:
>> > > On Thu, 28 Apr 2011, john stultz wrote:
>> > > > On Thu, 2011-04-28 at 23:04 +0200, Thomas Gleixner wrote:
>> > > > > /me suspects hrtimer changes to be the real culprit.
>> > > >
>> > > > I'm not seeing anything on right off, but it does smell like
>> > > > e06383db9ec591696a06654257474b85bac1f8cb would be where such an issue
>> > > > would crop up.
>> > > >
>> > > > Bruno, could you try checking out e06383db9ec, confirming it still
>> > > > occurs (and then maybe seeing if it goes away at e06383db9ec^1)?
>> > > >
>> > > > I'll keep digging in the meantime.
>> > >
>> > > I found the bug already. The problem is that sched_init() calls
>> > > init_rt_bandwidth() which calls hrtimer_init() _BEFORE_
>> > > hrtimers_init() is called.
>> > >
>> > > That was unnoticed so far as the CLOCK id to hrtimer base conversion
>> > > was hardcoded. Now we use a table which is set up at hrtimers_init(),
>> > > so the bandwith hrtimer ends up on CLOCK_REALTIME because the table is
>> > > in the bss.
>> > >
>> > > The patch below fixes this, by providing the table statically rather
>> > > than runtime initialized. Though that whole ordering wants to be
>> > > revisited.
>> >
>> > Works here as well (applied alone), /proc/$(pidof rcu_kthread)/sched shows
>> > total runtime continuing to increase beyond 950 and slubs continue being
>> > released!
>>
>> Does the CPU time show up in top/ps as well now ?
>
> Yes, it does (currently at 0:09 in ps for 9336.075 in
> /proc/$(pidof rcu_kthread)/sched)
>
> Thanks,
> Bruno
>

Just FYI: The patch is now in mainline (2.6.39-rc5-git3).

- Sedat -

[1] http://git.us.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=ce31332d3c77532d6ea97ddcb475a2b02dd358b4
[2] http://www.kernel.org/diff/diffview.cgi?file=/pub/linux/kernel/v2.6/snapshots/patch-2.6.39-rc5-git3.bz2

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