Re: [PATCH v7 1/2] blk-throtl: introduce a new flag THROTL_TG_CANCELING

[yukuai (C)]

在 2022/02/07 16:15, Ming Lei 写道:
> On Fri, Jan 28, 2022 at 04:45:21PM +0800, Yu Kuai wrote:
> > If the new flag is set, then the throtl_grp will stop throttling bios.
> > Prepare to canceling all throttled bios if the disk is gone.
> >
> > Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx>
> > ---
> >   block/blk-throttle.c | 17 +++++++++++++----
> >   1 file changed, 13 insertions(+), 4 deletions(-)
> >
> > diff --git a/block/blk-throttle.c b/block/blk-throttle.c
> > index 7c462c006b26..abc5e506c72d 100644
> > --- a/block/blk-throttle.c
> > +++ b/block/blk-throttle.c
> > @@ -43,8 +43,12 @@
> >   static struct workqueue_struct *kthrotld_workqueue;
> >   
> >   enum tg_state_flags {
> > -	THROTL_TG_PENDING	= 1 << 0,	/* on parent's pending tree */
> > -	THROTL_TG_WAS_EMPTY	= 1 << 1,	/* bio_lists[] became non-empty */
> > +	/* on parent's pending tree */
> > +	THROTL_TG_PENDING	= 1 << 0,
> > +	/* bio_lists[] became non-empty */
> > +	THROTL_TG_WAS_EMPTY	= 1 << 1,
> > +	/* starts to cancel all bios, will be set if the disk is deleted */
> > +	THROTL_TG_CANCELING	= 1 << 2,
> >   };
> >   
> >   #define rb_entry_tg(node)	rb_entry((node), struct throtl_grp, rb_node)
> > @@ -871,7 +875,8 @@ static bool tg_may_dispatch(struct throtl_grp *tg, struct bio *bio,
> >   	       bio != throtl_peek_queued(&tg->service_queue.queued[rw]));
> >   
> >   	/* If tg->bps = -1, then BW is unlimited */
> > -	if (bps_limit == U64_MAX && iops_limit == UINT_MAX) {
> > +	if ((bps_limit == U64_MAX && iops_limit == UINT_MAX) ||
> > +	    tg->flags & THROTL_TG_CANCELING) {
> >   		if (wait)
> >   			*wait = 0;
> >   		return true;
> > @@ -974,6 +979,9 @@ static void tg_update_disptime(struct throtl_grp *tg)
> >   	unsigned long read_wait = -1, write_wait = -1, min_wait = -1, disptime;
> >   	struct bio *bio;
> >   
> > +	if (tg->flags & THROTL_TG_CANCELING)
> > +		goto update;
> > +
>
> The above change and the following one in tg_update_disptime() isn't
> needed actually.
>
> Also I'd suggest to fold the two into one patch.

Ok, I'll fold the two in next version.

Thanks,
Kuai
> Thanks,
> Ming
>
> .