Re: [PATCH V2] block: Prevent hung_check firing during long sync IO

[Jens Axboe <axboe@kernel.dk>]

On 3/17/20 9:43 PM, Ming Lei wrote:
> submit_bio_wait() can be called from ioctl(BLKSECDISCARD), which
> may take long time to complete, as Salman mentioned, 4K BLKSECDISCARD
> takes up to 100 second on some devices. Also any block I/O operation
> that occurs after the BLKSECDISCARD is submitted will also potentially
> be affected by the hung task timeouts.
> 
> Another report is that task hang can be observed when running mkfs
> over raid10 which takes a small max discard sectors limit because
> of chunk size.
> 
> So prevent hung_check from firing by taking same approach used
> in blk_execute_rq(), and the wake-up interval is set as half the
> hung_check timer period, which keeps overhead low enough.

Applied, thanks.

We have two of these similar constructs now in block alone, I wonder
if there are others in other sub-systems. Might make sense to make
this a generic helper at some point.

-- 
Jens Axboe