From: Peter Zijlstra <peterz@infradead.org>
To: Jan Kara <jack@suse.cz>
Cc: Wu Fengguang <fengguang.wu@intel.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org
Subject: Re: [PATCH 2/2] block: Convert BDI proportion calculations to flexible proportions
Date: Fri, 18 May 2012 00:04:33 +0200 [thread overview]
Message-ID: <1337292273.4281.101.camel@twins> (raw)
In-Reply-To: <1337096583-6049-3-git-send-email-jack@suse.cz>
On Tue, 2012-05-15 at 17:43 +0200, Jan Kara wrote:
> +static struct timer_list writeout_period_timer =
> + TIMER_DEFERRED_INITIALIZER(writeout_period, 0, 0);
So the problem with using a deferred timer is that it 'ignores' idle
time. So if a very busy period is followed by a real quiet period you'd
expect all the proportions to have aged to 0, but they won't have.
One way to solve that is to track a jiffies count of the last time the
timer triggered and compute the missed periods from that and extend
fprop_new_period() to deal with period increments of more than 1.
The other is of course to not use deferred timers.
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next prev parent reply other threads:[~2012-05-17 22:04 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-15 15:43 [PATCH 0/2 v3] Flexible proportions Jan Kara
2012-05-15 15:43 ` [PATCH 1/2] lib: Proportions with flexible period Jan Kara
2012-05-17 21:35 ` Peter Zijlstra
2012-05-18 14:33 ` Jan Kara
2012-05-17 21:56 ` Peter Zijlstra
2012-05-18 14:42 ` Jan Kara
2012-05-18 10:43 ` Peter Zijlstra
2012-05-18 14:45 ` Jan Kara
2012-05-15 15:43 ` [PATCH 2/2] block: Convert BDI proportion calculations to flexible proportions Jan Kara
2012-05-17 22:04 ` Peter Zijlstra [this message]
2012-05-18 14:24 ` Jan Kara
2012-05-18 14:34 ` Peter Zijlstra
-- strict thread matches above, loose matches on Subject: below --
2012-05-24 16:59 [PATCH 0/2 v4] Flexible proportions Jan Kara
2012-05-24 16:59 ` [PATCH 2/2] block: Convert BDI proportion calculations to flexible proportions Jan Kara
2012-05-28 15:49 ` Sasha Levin
2012-05-29 12:34 ` Jan Kara
2012-05-29 12:38 ` Peter Zijlstra
2012-05-29 12:54 ` Jan Kara
2012-05-31 22:11 ` Jan Kara
2012-05-31 22:26 ` Peter Zijlstra
2012-05-31 22:42 ` Jan Kara
2012-06-01 3:10 ` Fengguang Wu
2012-06-01 10:13 ` Peter Zijlstra
2012-05-03 22:39 [PATCH 0/2 v2] Flexible proportions for BDIs Jan Kara
2012-05-03 22:39 ` [PATCH 2/2] block: Convert BDI proportion calculations to flexible proportions Jan Kara
2012-05-07 14:47 ` Fengguang Wu
2012-05-07 15:21 ` Peter Zijlstra
2012-05-09 11:38 ` Jan Kara
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