From: Peter Zijlstra <peterz@infradead.org>
To: Richard Kennedy <richard@rsk.demon.co.uk>
Cc: Jens Axboe <axboe@kernel.dk>,
Andrew Morton <akpm@linux-foundation.org>,
Wu Fengguang <fengguang.wu@intel.com>,
lkml <linux-kernel@vger.kernel.org>,
linux-mm <linux-mm@kvack.org>
Subject: Re: [RFC PATCH] mm: let the bdi_writeout fraction respond more quickly
Date: Wed, 16 Jun 2010 20:54:26 +0200 [thread overview]
Message-ID: <1276714466.1745.625.camel@laptop> (raw)
In-Reply-To: <1276526681.1980.89.camel@castor.rsk>
On Mon, 2010-06-14 at 15:44 +0100, Richard Kennedy wrote:
> > diff --git a/mm/page-writeback.c b/mm/page-writeback.c
> > index 2fdda90..315dd04 100644
> > --- a/mm/page-writeback.c
> > +++ b/mm/page-writeback.c
> > @@ -144,7 +144,7 @@ static int calc_period_shift(void)
> > else
> > dirty_total = (vm_dirty_ratio * determine_dirtyable_memory()) /
> > 100;
> > - return 2 + ilog2(dirty_total - 1);
> > + return ilog2(dirty_total - 1) - 4;
> > }
IIRC I suggested similar things in the past and all we needed to do was
find people doing the measurements on different bits of hardware or so..
I don't have any problems with the approach, all we need to make sure is
that we never return 0 or a negative number (possibly ensure a minimum
positive shift value).
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next prev parent reply other threads:[~2010-06-16 18:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-14 13:58 [RFC PATCH] mm: let the bdi_writeout fraction respond more quickly Richard Kennedy
2010-06-14 14:44 ` Richard Kennedy
2010-06-16 18:54 ` Peter Zijlstra [this message]
2010-06-17 11:39 ` Richard Kennedy
2010-06-17 11:41 ` Jens Axboe
2010-06-17 18:45 ` Richard Kennedy
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