Re: [PATCH 0/11] Per-bdi writeback flusher threads v9

From: Jens Axboe
Date: Fri May 29 2009 - 13:09:25 EST

On Fri, May 29 2009, Artem Bityutskiy wrote:
> Artem Bityutskiy wrote:
>> Jens Axboe wrote:
>>> Hi,
>>> Here's the 9th version of the writeback patches. Changes since v8:
>>> - Fix a bdi_work on-stack allocation hang. I hope this fixes Ted's
>>> issue.
>>> - Get rid of the explicit wait queues, we can just use wake_up_process()
>>> since it's just for that one task.
>>> - Add separate "sync_supers" thread that makes sure that the dirty
>>> super blocks get written. We cannot safely do this from
>>> bdi_forker_task(),
>>> as that risks deadlocking on ->s_umount. Artem, I implemented this
>>> by doing the wake ups from a timer so that it would be easier for you
>>> to just deactivate the timer when there are no super blocks.
>>> For ease of patching, I've put the full diff here:
>>> and also stored this in a writeback-v9 branch that will not change,
>>> you can pull that into Linus tree from here:
>>> git:// writeback-v9
>> I'm working with the above branch. Got the following twice.
>> Not sure what triggers this, probably if I do nothing and
>> cpufreq starts doing its magic, this is triggered.
>> And I'm not sure it has something to do with your changes,
>> it is just that I saw this only with your tree. Please,
>> ignore if this is not relevant.
> Sorry, probably I shouldn't have reported this before looking
> closer. I'll investigate this later and fine out whether it
> is related to your work or not. Sorry for too early and probably
> false alarm.

No problem. If it does turn out to have some relation to the writeback
stuff, let me know.

Jens Axboe

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