LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: David Rientjes <rientjes@google.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Christoph Lameter <cl@linux-foundation.org>,
	Nick Piggin <npiggin@suse.de>, Paul Menage <menage@google.com>,
	Derek Fults <dfults@sgi.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [patch 3/7] mm: make page writeback obey cpuset constraints
Date: Thu, 30 Oct 2008 02:10:24 -0700 (PDT)	[thread overview]
Message-ID: <alpine.DEB.2.00.0810300203360.29917@chino.kir.corp.google.com> (raw)
In-Reply-To: <1225356120.7803.5.camel@twins>

On Thu, 30 Oct 2008, Peter Zijlstra wrote:

> On Tue, 2008-10-28 at 12:18 -0700, David Rientjes wrote:
> > On Tue, 28 Oct 2008, Peter Zijlstra wrote:
> > 
> > > > +	is_subset = cpuset_populate_dirty_limits(dl, &dirtyable_memory,
> > > > +						 &nr_mapped, nodes);
> > > > +	if (!is_subset) {
> > > > +		dl->nr_dirty = global_page_state(NR_FILE_DIRTY);
> > > > +		dl->nr_unstable = global_page_state(NR_UNSTABLE_NFS);
> > > > +		dl->nr_writeback = global_page_state(NR_WRITEBACK);
> > > > +		dirtyable_memory = determine_dirtyable_memory();
> > > > +		nr_mapped = global_page_state(NR_FILE_MAPPED) +
> > > > +			global_page_state(NR_ANON_PAGES);
> > > > +	} else
> > > > +		dirtyable_memory -= highmem_dirtyable_memory(nodes,
> > > > +							dirtyable_memory);
> > > 
> > > Why not fold that all into cpuset_populate_dirty_limits() ?
> > > 
> > 
> > cpuset_populate_dirty_limits() is a no-op on !CONFIG_CPUSETS kernels.
> 
> Right, humm. Maybe introduce a populate_dirty_limits() and differentiate
> that between CONFIG_CPUSETS and not, and make it do everything.
> 
> That would get rid of this fudge I think, no?
> 

I agree it would look much cleaner and I actually did that originally, but 
it requires adding #ifdef's for CONFIG_CPUSETS to mm/page-writeback.c 
since highmem_dirtyable_memory() is static.

There's actually nothing cpuset-specific about 
cpuset_populate_dirty_limits() and it could be used for !CONFIG_CPUSETS 
kernels, but there's a performance benefit of using the global ZVC values 
for the page stats as opposed to iterating over each node and adding their 
respective values.  So is_subset is only non-zero when the passed nodemask 
excludes system nodes (the cpuset case), and we must iterate the node ZVC 
values.

So perhaps the solution is to introduce populate_nodemask_dirty_limits() 
and populate_global_dirty_limits() both in mm/page-writeback.c?

  reply	other threads:[~2008-10-30  9:11 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-10-28 16:08 [patch 1/7] cpusets: add dirty map to struct address_space David Rientjes
2008-10-28 16:08 ` [patch 2/7] pdflush: allow the passing of a nodemask parameter David Rientjes
2008-10-28 16:08 ` [patch 3/7] mm: make page writeback obey cpuset constraints David Rientjes
2008-10-28 17:31   ` Peter Zijlstra
2008-10-28 19:16     ` David Rientjes
2008-10-28 17:32   ` Peter Zijlstra
2008-10-28 19:18     ` David Rientjes
2008-10-30  8:42       ` Peter Zijlstra
2008-10-30  9:10         ` David Rientjes [this message]
2008-10-30  9:34           ` Peter Zijlstra
2008-10-28 16:08 ` [patch 4/7] mm: cpuset aware reclaim writeout David Rientjes
2008-10-28 16:08 ` [patch 5/7] mm: throttle writeout with cpuset awareness David Rientjes
2008-10-28 16:08 ` [patch 6/7] cpusets: per cpuset dirty ratios David Rientjes
2008-10-30  6:59   ` Paul Menage
2008-10-30  8:48     ` David Rientjes
2008-10-30 15:28     ` Christoph Lameter
2008-10-30  8:44   ` Peter Zijlstra
2008-10-30  9:03     ` David Rientjes
2008-10-30  9:34       ` Peter Zijlstra
2008-10-30 10:02         ` David Rientjes
2008-10-28 16:08 ` [patch 7/7] cpusets: update documentation for writeback throttling David Rientjes
2008-10-30 16:06   ` Christoph Lameter
2008-10-28 17:37 ` [patch 1/7] cpusets: add dirty map to struct address_space Peter Zijlstra
2008-10-28 20:48   ` David Rientjes
2008-10-29  1:13     ` David Rientjes
2008-10-29  2:24       ` David Rientjes
2008-10-30  8:38       ` Peter Zijlstra
2008-10-28 17:46 ` Peter Zijlstra
2008-10-28 19:19   ` David Rientjes
2008-10-30 19:23 [patch 0/7] cpuset writeback throttling David Rientjes
2008-10-30 19:23 ` [patch 3/7] mm: make page writeback obey cpuset constraints David Rientjes

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=alpine.DEB.2.00.0810300203360.29917@chino.kir.corp.google.com \
    --to=rientjes@google.com \
    --cc=akpm@linux-foundation.org \
    --cc=cl@linux-foundation.org \
    --cc=dfults@sgi.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=menage@google.com \
    --cc=npiggin@suse.de \
    --cc=peterz@infradead.org \
    --subject='Re: [patch 3/7] mm: make page writeback obey cpuset constraints' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).