> Il giorno 12 gen 2018, alle ore 11:15, Holger Hoffstätte <holger@xxxxxxxxxxxxxxxxxxxxxx> ha scritto:
>
> On 01/12/18 06:58, Paolo Valente wrote:
>>
>>
>>> Il giorno 28 dic 2017, alle ore 15:00, Holger Hoffstätte <holger@xxxxxxxxxxxxxxxxxxxxxx> ha scritto:
>>>
>>>
>>> On 12/28/17 12:19, Paolo Valente wrote:
>>> (snip half a tech report ;)
>>>
>>> So either this or the previous patch ("limit tags for writes and async I/O"
>>> can lead to a hard, unrecoverable hang with heavy writes. Since I couldn't
>>> log into the affected system anymore I couldn't get any stack traces, blk-mq
>>> debug output etc. but there was nothing in dmesg/on the console, so it
>>> wasn't a BUG/OOPS.
>>>
>>> -h
>>
>> Hi Holger,
>> if, as I guess, this problem hasn't gone away for you, I have two
>> requests:
>> 1) could you share your exact test
>> 2) if nothing happens in my systems with your test, would you be
>> willing to retry with the dev version of bfq? It should be able to
>> tell us what takes to your hang. If you are willing to do this test,
>> I'll prepare a branch with everything already configured for you.
>
> Hi,
>
> thanks for following up but there's no need for any of that; it turned out
> to be something else since I got the same hang without those patches at
> least once (during a btrfs balance, even though it didn't look like btrfs'
> fault directly; more like block/mm/helpers.
>
> So on January 7 I posted to linux-block et.al. where I said
> "So this turned out to be something else, sorry for the false alarm."
> but apparently that didn't make it through since it's not in the
> archives either. Sorry.
>
> Long story short, the good news is that I've been running with both patches
> since then without any issue. :)
>
Wow, what a relief! :)
So, Jens, being the only issue reported gone, can you please consider
queueing this patch and the other pending one [1]? They are both
critical for bfq performance.
Thanks,
Paolo
[1] https://www.spinics.net/lists/kernel/msg2684463.html
> cheers
> Holger
