Messages in this thread | | | Date | Mon, 16 Apr 2018 16:15:12 +0800 | From | Ming Lei <> | Subject | Re: [PATCH] blk-mq: mark hctx RESTART when get budget fails |
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On Mon, Apr 16, 2018 at 03:55:36PM +0800, Jianchao Wang wrote: > When get budget fails, blk_mq_sched_dispatch_requests does not do > anything to ensure the hctx to be restarted. We can survive from > this, because only the scsi implements .get_budget and it always > runs the hctx queues when request is completed.
Exactly, that is why we don't handle the failure before dequeuing request.
I suggest to just document this usage now.
> > Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> > --- > block/blk-mq-sched.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c > index 25c14c5..49e7cd9 100644 > --- a/block/blk-mq-sched.c > +++ b/block/blk-mq-sched.c > @@ -102,8 +102,10 @@ static void blk_mq_do_dispatch_sched(struct blk_mq_hw_ctx *hctx) > !e->type->ops.mq.has_work(hctx)) > break; > > - if (!blk_mq_get_dispatch_budget(hctx)) > + if (!blk_mq_get_dispatch_budget(hctx)) { > + blk_mq_sched_mark_restart_hctx(hctx);
The RESTART flag still may not take into effect if all requests are completed before calling blk_mq_sched_mark_restart_hctx().
> break; > + } > > rq = e->type->ops.mq.dispatch_request(hctx); > if (!rq) { > @@ -148,8 +150,10 @@ static void blk_mq_do_dispatch_ctx(struct blk_mq_hw_ctx *hctx) > if (!sbitmap_any_bit_set(&hctx->ctx_map)) > break; > > - if (!blk_mq_get_dispatch_budget(hctx)) > + if (!blk_mq_get_dispatch_budget(hctx)) { > + blk_mq_sched_mark_restart_hctx(hctx);
Same with above.
Thanks, Ming
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