Re: [PATCH 2/2] Fix occasional hangs on mutexes

[Jens Axboe <axboe@kernel.dk>]

On 05/25/2016 01:27 PM, Jens Axboe wrote:
> On 05/24/2016 09:03 AM, Jan Kara wrote:
>> When running xfstest generic/299 using fio on my test machine using
>> ramdisk as a backing store, I have noticed that fio often hangs waiting
>> for td->io_u_lock. After some debugging I have found out the reason is
>> that mutexes are created as process-private by default and but this
>> mutex is actually manipulated from several processes. The hang is not
>> obvious immediately as the mutex is located in shared memory and thus
>> while the locking is resolved in userspace, everything works as
>> expected. Only once we use kernel futexes, the process is not properly
>> woken up when futex is released.
>>
>> Fix the problem by marking all mutexes and conditional variables that
>> are located in shared memory as shared.
>
> Thanks Jan, applied both 1 and 2.
>
> Would be nice to factor out the cv/mutex init code, so we don't have to
> essentially copy/paste it wherever we want to have process shared
> mutexes or cond vars.

I did that:

http://git.kernel.dk/cgit/fio/commit/?id=34febb23fa9c7b9b0d54c324effff1a808a8fe6e

-- 
Jens Axboe