From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
miklos@szeredi.hu, neilb@suse.de, dgc@sgi.com,
tomoki.sekiyama.qu@hitachi.com, nikita@clusterfs.com
Subject: Re: [PATCH 12/12] mm: per BDI congestion feedback
Date: Fri, 06 Apr 2007 09:01:57 +0200 [thread overview]
Message-ID: <1175842917.6483.130.camel@twins> (raw)
In-Reply-To: <20070405162425.eb78c701.akpm@linux-foundation.org>
On Thu, 2007-04-05 at 16:24 -0700, Andrew Morton wrote:
> On Thu, 05 Apr 2007 19:42:21 +0200
> root@programming.kicks-ass.net wrote:
>
> > Now that we have per BDI dirty throttling is makes sense to also have oer BDI
> > congestion feedback; why wait on another device if the current one is not
> > congested.
>
> Similar comments apply. congestion_wait() should be called
> throttle_at_a_rate_proportional_to_the_speed_of_presently_uncongested_queues().
>
> If a process is throttled in the page allocator waiting for pages to become
> reclaimable, that process absolutely does not care whether those pages were
> previously dirty against /dev/sda or against /dev/sdb. It wants to be woken
> up for writeout completion against any queue.
OK, so you disagree with Miklos' 2nd point here:
http://lkml.org/lkml/2007/4/4/137
And in the light of clear_bdi_congestion() being called for each
writeout completion under the threshold this does make sense.
So this whole 8-12/12 series is not needed and just served as an
learning experience :-/
WARNING: multiple messages have this Message-ID (diff)
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
miklos@szeredi.hu, neilb@suse.de, dgc@sgi.com,
tomoki.sekiyama.qu@hitachi.com, nikita@clusterfs.com
Subject: Re: [PATCH 12/12] mm: per BDI congestion feedback
Date: Fri, 06 Apr 2007 09:01:57 +0200 [thread overview]
Message-ID: <1175842917.6483.130.camel@twins> (raw)
In-Reply-To: <20070405162425.eb78c701.akpm@linux-foundation.org>
On Thu, 2007-04-05 at 16:24 -0700, Andrew Morton wrote:
> On Thu, 05 Apr 2007 19:42:21 +0200
> root@programming.kicks-ass.net wrote:
>
> > Now that we have per BDI dirty throttling is makes sense to also have oer BDI
> > congestion feedback; why wait on another device if the current one is not
> > congested.
>
> Similar comments apply. congestion_wait() should be called
> throttle_at_a_rate_proportional_to_the_speed_of_presently_uncongested_queues().
>
> If a process is throttled in the page allocator waiting for pages to become
> reclaimable, that process absolutely does not care whether those pages were
> previously dirty against /dev/sda or against /dev/sdb. It wants to be woken
> up for writeout completion against any queue.
OK, so you disagree with Miklos' 2nd point here:
http://lkml.org/lkml/2007/4/4/137
And in the light of clear_bdi_congestion() being called for each
writeout completion under the threshold this does make sense.
So this whole 8-12/12 series is not needed and just served as an
learning experience :-/
--
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next prev parent reply other threads:[~2007-04-06 7:02 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-04-05 17:42 [PATCH 00/12] per device dirty throttling -v3 root
2007-04-05 17:42 ` root
2007-04-05 17:42 ` [PATCH 01/12] nfs: remove congestion_end() root
2007-04-05 17:42 ` root
2007-04-05 17:42 ` [PATCH 02/12] mm: scalable bdi statistics counters root
2007-04-05 17:42 ` root
2007-04-05 22:37 ` Andrew Morton
2007-04-05 22:37 ` Andrew Morton
2007-04-06 7:22 ` Peter Zijlstra
2007-04-06 7:22 ` Peter Zijlstra
2007-04-05 17:42 ` [PATCH 03/12] mm: count dirty pages per BDI root
2007-04-05 17:42 ` root
2007-04-05 17:42 ` [PATCH 04/12] mm: count writeback " root
2007-04-05 17:42 ` root
2007-04-05 17:42 ` [PATCH 05/12] mm: count unstable " root
2007-04-05 17:42 ` root
2007-04-05 17:42 ` [PATCH 06/12] mm: expose BDI statistics in sysfs root
2007-04-05 17:42 ` root
2007-04-05 17:42 ` [PATCH 07/12] mm: per device dirty threshold root
2007-04-05 17:42 ` root
2007-04-05 17:42 ` [PATCH 08/12] mm: fixup possible deadlock root
2007-04-05 17:42 ` root
2007-04-05 22:43 ` Andrew Morton
2007-04-05 22:43 ` Andrew Morton
2007-04-05 17:42 ` [PATCH 09/12] mm: remove throttle_vm_writeback root
2007-04-05 17:42 ` root
2007-04-05 22:44 ` Andrew Morton
2007-04-05 22:44 ` Andrew Morton
2007-09-26 20:42 ` Peter Zijlstra
2007-09-26 20:42 ` Peter Zijlstra
2007-04-05 17:42 ` [PATCH 10/12] mm: page_alloc_wait root
2007-04-05 17:42 ` root
2007-04-05 22:57 ` Andrew Morton
2007-04-05 22:57 ` Andrew Morton
2007-04-06 6:37 ` Peter Zijlstra
2007-04-06 6:37 ` Peter Zijlstra
2007-04-05 17:42 ` [PATCH 11/12] mm: accurate pageout congestion wait root
2007-04-05 17:42 ` root
2007-04-05 23:17 ` Andrew Morton
2007-04-05 23:17 ` Andrew Morton
2007-04-06 6:51 ` Peter Zijlstra
2007-04-06 6:51 ` Peter Zijlstra
2007-04-05 17:42 ` [PATCH 12/12] mm: per BDI congestion feedback root
2007-04-05 17:42 ` root
2007-04-05 23:24 ` Andrew Morton
2007-04-05 23:24 ` Andrew Morton
2007-04-06 7:01 ` Peter Zijlstra [this message]
2007-04-06 7:01 ` Peter Zijlstra
2007-04-06 11:00 ` Andrew Morton
2007-04-06 11:00 ` Andrew Morton
2007-04-06 11:10 ` Miklos Szeredi
2007-04-06 11:10 ` Miklos Szeredi
2007-04-05 17:47 ` [PATCH 00/12] per device dirty throttling -v3 Peter Zijlstra
2007-04-05 17:47 ` Peter Zijlstra
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