From: "John Stoffel" <john@stoffel.org>
To: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
miklos@szeredi.hu, akpm@linux-foundation.org, neilb@suse.de,
dgc@sgi.com, tomoki.sekiyama.qu@hitachi.com,
nikita@clusterfs.com, trond.myklebust@fys.uio.no,
yingchao.zhou@gmail.com, richard@rsk.demon.co.uk,
torvalds@linux-foundation.org
Subject: Re: [PATCH 00/23] per device dirty throttling -v10
Date: Tue, 11 Sep 2007 22:31:32 -0400 [thread overview]
Message-ID: <18151.20356.862163.430265@stoffel.org> (raw)
In-Reply-To: <20070911195350.825778000@chello.nl>
Peter> Per device dirty throttling patches These patches aim to
Peter> improve balance_dirty_pages() and directly address three
Peter> issues:
Peter> 1) inter device starvation
Peter> 2) stacked device deadlocks
Peter> 3) inter process starvation
Peter> 1 and 2 are a direct result from removing the global dirty
Peter> limit and using per device dirty limits. By giving each device
Peter> its own dirty limit is will no longer starve another device,
Peter> and the cyclic dependancy on the dirty limit is broken.
Ye haa! This should be a big improvement.
Peter> In order to efficiently distribute the dirty limit across the
Peter> independant devices a floating proportion is used, this will
Peter> allocate a share of the total limit proportional to the
Peter> device's recent activity.
I'm not sure I like or agree with this. Shouldn't we be limiting
based on the device's capability to sustain traffic? So if I have a
RAID device which can read/write a total of 100Mb/sec, while at the
same time I've got a CF device which can do 5Mb/sec, shouldn't we be
more strongly limiting the CF device, even if it is the only device
being written to?
Of course, I haven't read the patches yet, nor am I qualified to
comment on them in any meanginful way I think. Hopefully I'm just
missing something key here in the explanation.
Peter> 3 is done by also scaling the dirty limit proportional to the
Peter> current task's recent dirty rate.
Do you mean task or device here? I'm just wondering how well this
works with a bunch of devices with wildly varying speeds.
John
next prev parent reply other threads:[~2007-09-12 2:32 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-09-11 19:53 [PATCH 00/23] per device dirty throttling -v10 Peter Zijlstra
2007-09-11 19:53 ` [PATCH 01/23] nfs: remove congestion_end() Peter Zijlstra
2007-09-11 19:53 ` [PATCH 02/23] lib: percpu_counter_add Peter Zijlstra
2007-09-11 19:53 ` [PATCH 03/23] lib: percpu_counter_sub Peter Zijlstra
2007-09-11 19:53 ` [PATCH 04/23] lib: percpu_counter variable batch Peter Zijlstra
2007-09-11 19:53 ` [PATCH 05/23] lib: make percpu_counter_add take s64 Peter Zijlstra
2007-09-11 19:53 ` [PATCH 06/23] lib: percpu_counter_set Peter Zijlstra
2007-09-11 19:53 ` [PATCH 07/23] lib: percpu_counter_sum_positive Peter Zijlstra
2007-09-11 19:53 ` [PATCH 08/23] lib: percpu_count_sum() Peter Zijlstra
2007-09-11 19:53 ` [PATCH 09/23] lib: percpu_counter_init error handling Peter Zijlstra
2007-09-11 19:54 ` [PATCH 10/23] lib: percpu_counter_init_irq Peter Zijlstra
2007-09-11 19:54 ` [PATCH 11/23] mm: bdi init hooks Peter Zijlstra
2007-09-11 19:54 ` [PATCH 12/23] containers: " Peter Zijlstra
2007-09-11 19:54 ` [PATCH 13/23] mtd: " Peter Zijlstra
2007-09-11 19:54 ` [PATCH 14/23] mtd: clean up the backing_dev_info usage Peter Zijlstra
2007-09-11 19:54 ` [PATCH 15/23] mtd: give mtdconcat devices their own backing_dev_info Peter Zijlstra
2007-09-11 19:54 ` [PATCH 16/23] mm: scalable bdi statistics counters Peter Zijlstra
2007-09-11 19:54 ` [PATCH 17/23] mm: count reclaimable pages per BDI Peter Zijlstra
2007-09-11 19:54 ` [PATCH 18/23] mm: count writeback " Peter Zijlstra
2007-09-11 19:54 ` [PATCH 19/23] mm: expose BDI statistics in sysfs Peter Zijlstra
2007-09-11 19:54 ` [PATCH 20/23] lib: floating proportions Peter Zijlstra
2007-09-11 19:54 ` [PATCH 21/23] mm: per device dirty threshold Peter Zijlstra
2007-09-12 2:36 ` John Stoffel
2007-09-12 8:45 ` Peter Zijlstra
2007-09-11 19:54 ` [PATCH 22/23] mm: dirty balancing for tasks Peter Zijlstra
2007-09-11 19:54 ` [PATCH 23/23] debug: sysfs files for the current ratio/size/total Peter Zijlstra
2007-09-12 2:31 ` John Stoffel [this message]
2007-09-12 9:00 ` [PATCH 00/23] per device dirty throttling -v10 Peter Zijlstra
-- strict thread matches above, loose matches on Subject: below --
2007-09-13 23:13 Tobias Oetiker
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=18151.20356.862163.430265@stoffel.org \
--to=john@stoffel.org \
--cc=a.p.zijlstra@chello.nl \
--cc=akpm@linux-foundation.org \
--cc=dgc@sgi.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=miklos@szeredi.hu \
--cc=neilb@suse.de \
--cc=nikita@clusterfs.com \
--cc=richard@rsk.demon.co.uk \
--cc=tomoki.sekiyama.qu@hitachi.com \
--cc=torvalds@linux-foundation.org \
--cc=trond.myklebust@fys.uio.no \
--cc=yingchao.zhou@gmail.com \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox