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

Artem Bityutskiy
2009-06-03T08:11:58Z

ext Jens Axboe wrote:
> 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:
>>>>
>>>> http://kernel.dk/writeback-v9.patch
>>>>
>>>> and also stored this in a writeback-v9 branch that will not change,
>>>> you can pull that into Linus tree from here:
>>>>
>>>> git://git.kernel.dk/linux-2.6-block.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.

OK, I'm confirming that I observe this also with pure 2.6.30-rc7
as well.

--
Best Regards,
Artem Bityutskiy (Артём Битюцкий)