Re: [PATCH] bcache: fix uninterruptible sleep in writeback thread

[Jens Axboe <axboe@kernel.dk>]

On 05/15/2014 02:02 AM, Francis Moreau wrote:
> Hello Jens,
> 
> On 05/12/2014 08:27 PM, Peter Kieser wrote:
>>
>> On 2014-05-05 3:30 PM, Nikolay Amiantov wrote:
>>> 2014-05-02 1:52 GMT+04:00 Slava Pestov <sp@datera.io>:
>>>> There were two issues here:
>>>>
>>>> - writeback thread did not start until the device first became dirty
>>>> - writeback thread used uninterruptible sleep once running
>>>>
>>>> Without this patch I see kernel warnings printed and a load average of
>>>> 1.52 after booting my test VM. With this patch the warnings are gone and
>>>> the load average is near 0.00 as expected.
>>> I've tried this patch and it has indeed fixed [1]! Thanks!
>>>
>>> [1]: https://bugzilla.kernel.org/show_bug.cgi?id=69471
>>
>> Kent,
>>
>> Could you please review this patch, and have it pushed upstream?
>>
> 
> Would it be possible to merge this patch directly before 3.15 is being
> released since kent don't seem to care about bugs in bcache or maybe he
> does but very selectively ?
> 
> Also it would be great that stable trees will be fixed.
> 
> Eventually I would suggest to mark bcache as an experimental thing since
> it's really not ready for production, just take a look at the bcache
> mailing list to see why. At least people won't be disappointed when
> they'll use bcache and see ton of koops.

I'd really like to get Kent to weigh in on this. Sometimes it appears
straightforward to switch from uninterruptible to interruptible sleep,
but then signals get in the way.

-- 
Jens Axboe