Re: [PATCH RFC] fs/aio: fix sleeping while TASK_INTERRUPTIBLE

[Chris Mason <clm@fb.com>]

On Tue, Dec 23, 2014 at 1:43 PM, Benjamin LaHaise <bcrl@kvack.org> 
wrote:
> On Mon, Dec 22, 2014 at 07:16:25PM -0500, Chris Mason wrote:
>>  The 3.19 merge window brought in a great new warning to catch 
>> someone
>>  calling might_sleep with their state != TASK_RUNNING.  The idea was 
>> to
>>  find buggy code locking mutexes after calling prepare_to_wait(), 
>> kind
>>  of like this:
> ...
>>  This has been lightly tested and hasn't been benchmarked, so RFC for
>>  now.
> 
> This was on my list of things to look at today.
> 
> I'm not at all happy with this particular patch.  It looks like this 
> issue
> was introduced back in 3.10 by Kent's big overhaul of things.  The 
> main
> benefit Kent's changes achieved stems from holding ring_lock across 
> fetching
> multiple events rather than taking the spin lock for every event.  I'm
> going to see if I can come up with a simpler way of fixing this.

Works for me, the patch is mostly a (somewhat commented) list of all 
the places we're currently doing it wrong.

-chris



--
To unsubscribe, send a message with 'unsubscribe linux-aio' in
the body to majordomo@kvack.org.  For more info on Linux AIO,
see: http://www.kvack.org/aio/
Don't email: <a href=mailto:"aart@kvack.org">aart@kvack.org</a>