Re: [Bug 12832] New: kernel leaks a lot of memory

[Wu Fengguang <fengguang.wu@intel.com>]

On Thu, Mar 12, 2009 at 08:55:30AM +0200, Pierre Ossman wrote:
> On Thu, 12 Mar 2009 09:08:16 +0800
> Wu Fengguang <fengguang.wu@intel.com> wrote:
> 
> > On Wed, Mar 11, 2009 at 05:02:23PM +0200, Pierre Ossman wrote:
> > > On Wed, 11 Mar 2009 21:00:22 +0800
> > > Wu Fengguang <fengguang.wu@intel.com> wrote:
> > > 
> > > > 
> > > > I worked up a simple debugging patch. Since the missing pages are
> > > > continuously spanned, several stack dumping shall be enough to catch
> > > > the page consumer.
> > > > 
> > > > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> > > > index 27b8681..c0df7fd 100644
> > > > --- a/mm/page_alloc.c
> > > > +++ b/mm/page_alloc.c
> > > > @@ -1087,6 +1087,13 @@ again:
> > > >  			goto failed;
> > > >  	}
> > > >  
> > > > +	/* wfg - hunting the 40000 missing pages */
> > > > +	{
> > > > +		unsigned long pfn = page_to_pfn(page);
> > > > +		if (pfn > 0x1000 && (pfn & 0xfff) <= 1)
> > > > +			dump_stack();
> > > > +	}
> > > > +
> > > >  	__count_zone_vm_events(PGALLOC, zone, 1 << order);
> > > >  	zone_statistics(preferred_zone, zone);
> > > >  	local_irq_restore(flags);
> > > 
> > > This got very noisy, but here's what was in the ring buffer once it had
> > > booted.
> > 
> > It's about 20 stack dumps, hehe. Could you please paste some of them?
> > Thank you!
> > 
> 
> Ooops, I meant to attach the dmesg output. Let's try again. :)

Ooops, there're no ftrace in the dmesg. They are pretty normal
page faults. I overlooked the possibility of repeated alloc/free
cycles on the same pfn...

Anyway please go on with Steven's ftrace patchset :-)

Thanks,
Fengguang

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