Re: mmotm 2011-04-29 - wonky VmRSS and VmHWM values after swapping

[Andrew Morton]

On Tue, 10 May 2011 18:04:45 +0200
Peter Zijlstra <a.p.zijlstra@xxxxxxxxx> wrote:

> > hm, me too.  After boot, hald has a get_mm_counter(mm, MM_ANONPAGES) of
> > 0xffffffffffff3c27.  Bisected to Pater's
> > mm-extended-batches-for-generic-mmu_gather.patch, can't see how it did
> > that.
> > 
> 
> I haven't quite figured out how to reproduce, but does the below cure
> things? If so, it should probably be folded into the first patch
> (mm-mmu_gather-rework.patch?) since that is the one introducing this.
> 
> ---
> Subject: mm: Fix RSS zap_pte_range() accounting
> 
> Since we update the RSS counters when breaking out of the loop and
> release the PTE lock, we should start with fresh deltas when we
> restart the gather loop.
> 
> Reported-by: Valdis.Kletnieks@xxxxxx
> Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
> ---
> Index: linux-2.6/mm/memory.c
> ===================================================================
> --- linux-2.6.orig/mm/memory.c
> +++ linux-2.6/mm/memory.c
> @@ -1120,8 +1120,8 @@ static unsigned long zap_pte_range(struc
>  	spinlock_t *ptl;
>  	pte_t *pte;
>  
> -	init_rss_vec(rss);
>  again:
> +	init_rss_vec(rss);
>  	pte = pte_offset_map_lock(mm, pmd, addr, &ptl);
>  	arch_enter_lazy_mmu_mode();
>  	do {

That fixed the negative hald VmHWM output on my test box.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/