On 10/6/19 4:45 AM, Ming Lei wrote: > When all CPUs in one hctx are offline, we shouldn't run this hw queue > for completing request any more. > > So steal bios from the request, and resubmit them, and finally free > the request in blk_mq_hctx_notify_dead(). > > Cc: Bart Van Assche <[email protected]> > Cc: Hannes Reinecke <[email protected]> > Cc: Christoph Hellwig <[email protected]> > Cc: Thomas Gleixner <[email protected]> > Cc: Keith Busch <[email protected]> > Signed-off-by: Ming Lei <[email protected]> > --- > block/blk-mq.c | 48 +++++++++++++++++++++++++++++++++++++++++------- > 1 file changed, 41 insertions(+), 7 deletions(-) > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index d991c122abf2..0b35fdbd1f17 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -2280,10 +2280,30 @@ static int blk_mq_hctx_notify_online(unsigned int > cpu, struct hlist_node *node) > return 0; > } > > +static void blk_mq_resubmit_io(struct request *rq) > +{ > + struct bio_list list; > + struct bio *bio; > + > + bio_list_init(&list); > + blk_steal_bios(&list, rq); > + > + while (true) { > + bio = bio_list_pop(&list); > + if (!bio) > + break; > + > + generic_make_request(bio); > + } > + > + blk_mq_cleanup_rq(rq); > + blk_mq_end_request(rq, 0); > +} > + Hmm. Not sure if this is a good idea. Shouldn't we call 'blk_mq_end_request()' before calling generic_make_request()? otherwise the cloned request might be completed before original one, which looks a bit dodgy to me; and might lead to quite a recursion if we have several dead cpus to content with ...
Cheers, Hannes -- Dr. Hannes Reinecke Teamlead Storage & Networking [email protected] +49 911 74053 688 SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg HRB 247165 (AG München), GF: Felix Imendörffer
