Messages in this thread | | | Date | Tue, 21 Apr 2009 10:06:31 -0400 | From | Theodore Tso <> | Subject | Re: [PATCH 9/9] ext3: do not throttle metadata and journal IO |
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On Tue, Apr 21, 2009 at 10:30:02AM +0200, Andrea Righi wrote: > > We're trying to address also this issue, setting max dirty pages limit > per cgroup, and force a direct writeback when these limits are exceeded. > > In this case dirty ratio throttling should happen automatically because > the process will be throttled by the IO controller when it tries to > writeback the dirty pages and submit IO requests.
The challenge here will be the accounting; consider that you may have a file that had some of its pages in its page cache dirtied by a process in cgroup A. Now another process in cgroup B dirties some more pages. This could happen either via a mmap'ed file or via the standard read/write system calls. How do you track which dirty pages should be charged against which cgroup?
- Ted
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