Currently, blk-mq timeout path synchronizes against the usual
issue/completion path using a complex scheme involving atomic
bitflags, REQ_ATOM_*, memory barriers and subtle memory coherence
rules. Unfortunately, it contains quite a few holes.
There's a complex dancing around REQ_ATOM_STARTED and
On Mon, Jan 08, 2018 at 11:29:11PM +, Bart Van Assche wrote:
> Does "gstate" perhaps stand for "generation number and state"? If so, please
> mention this in one of the above comments.
Yeah, will do.
Thanks.
--
tejun
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On Mon, Jan 08, 2018 at 09:06:55PM +, Bart Van Assche wrote:
> On Mon, 2018-01-08 at 11:15 -0800, Tejun Heo wrote:
> > +static void blk_mq_rq_update_aborted_gstate(struct request *rq, u64 gstate)
> > +{
> > + unsigned long flags;
> > +
> > + local_irq_save(flags);
> > +
On Mon, 2018-01-08 at 11:15 -0800, Tejun Heo wrote:
> @@ -230,6 +232,27 @@ struct request {
>
> unsigned short write_hint;
>
> + /*
> + * On blk-mq, the lower bits of ->gstate carry the MQ_RQ_* state
> + * value and the upper bits the generation number which is
> + *
On Mon, 2018-01-08 at 11:15 -0800, Tejun Heo wrote:
> +static void blk_mq_rq_update_aborted_gstate(struct request *rq, u64 gstate)
> +{
> + unsigned long flags;
> +
> + local_irq_save(flags);
> + u64_stats_update_begin(>aborted_gstate_sync);
> + rq->aborted_gstate = gstate;
> +
Currently, blk-mq timeout path synchronizes against the usual
issue/completion path using a complex scheme involving atomic
bitflags, REQ_ATOM_*, memory barriers and subtle memory coherence
rules. Unfortunately, it contains quite a few holes.
There's a complex dancing around REQ_ATOM_STARTED and
