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Date: Thu, 4 Mar 2010 17:28:58 +0100
From: Andrea Righi <arighi@develer.com>
To: Vivek Goyal <vgoyal@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
       Balbir Singh <balbir@linux.vnet.ibm.com>,
       Peter Zijlstra <peterz@infradead.org>,
       Trond Myklebust <trond.myklebust@fys.uio.no>,
       Suleiman Souhlal <suleiman@google.com>,
       Greg Thelen <gthelen@google.com>,
       Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>,
       "Kirill A. Shutemov" <kirill@shutemov.name>,
       Andrew Morton <akpm@linux-foundation.org>,
       containers@lists.linux-foundation.org, linux-kernel@vger.kernel.org,
       linux-mm@kvack.org
Subject: Re: [PATCH -mmotm 4/4] memcg: dirty pages instrumentation
Message-ID: <20100304162858.GE4566@linux>
References: <1267699215-4101-1-git-send-email-arighi@develer.com>
 <1267699215-4101-5-git-send-email-arighi@develer.com>
 <20100304161828.GC18786@redhat.com>
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On Thu, Mar 04, 2010 at 11:18:28AM -0500, Vivek Goyal wrote:
> On Thu, Mar 04, 2010 at 11:40:15AM +0100, Andrea Righi wrote:
> 
> [..]
> > diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> > index 5a0f8f3..c5d14ea 100644
> > --- a/mm/page-writeback.c
> > +++ b/mm/page-writeback.c
> > @@ -137,13 +137,16 @@ static struct prop_descriptor vm_dirties;
> >   */
> >  static int calc_period_shift(void)
> >  {
> > +	struct dirty_param dirty_param;
> >  	unsigned long dirty_total;
> >  
> > -	if (vm_dirty_bytes)
> > -		dirty_total = vm_dirty_bytes / PAGE_SIZE;
> > +	get_dirty_param(&dirty_param);
> > +
> > +	if (dirty_param.dirty_bytes)
> > +		dirty_total = dirty_param.dirty_bytes / PAGE_SIZE;
> >  	else
> > -		dirty_total = (vm_dirty_ratio * determine_dirtyable_memory()) /
> > -				100;
> > +		dirty_total = (dirty_param.dirty_ratio *
> > +				determine_dirtyable_memory()) / 100;
> >  	return 2 + ilog2(dirty_total - 1);
> >  }
> >  
> > @@ -408,41 +411,46 @@ static unsigned long highmem_dirtyable_memory(unsigned long total)
> >   */
> >  unsigned long determine_dirtyable_memory(void)
> >  {
> > -	unsigned long x;
> > -
> > -	x = global_page_state(NR_FREE_PAGES) + global_reclaimable_pages();
> > +	unsigned long memory;
> > +	s64 memcg_memory;
> >  
> > +	memory = global_page_state(NR_FREE_PAGES) + global_reclaimable_pages();
> >  	if (!vm_highmem_is_dirtyable)
> > -		x -= highmem_dirtyable_memory(x);
> > -
> > -	return x + 1;	/* Ensure that we never return 0 */
> > +		memory -= highmem_dirtyable_memory(memory);
> > +	if (mem_cgroup_has_dirty_limit())
> > +		return memory + 1;
> 
> Should above be?
> 	if (!mem_cgroup_has_dirty_limit())
> 		return memory + 1;

Very true.

I'll post another patch with this and Kirill's fixes.

Thanks,
-Andrea

> 
> Vivek
> 
> > +	memcg_memory = mem_cgroup_page_stat(MEMCG_NR_DIRTYABLE_PAGES);
> > +	return min((unsigned long)memcg_memory, memory + 1);
> >  }