On Mon, Feb 05, 2018 at 07:54:29AM +0100, Hannes Reinecke wrote: > On 02/03/2018 05:21 AM, Ming Lei wrote: > > Quite a few HBAs(such as HPSA, megaraid, mpt3sas, ..) support multiple > > reply queues, but tags is often HBA wide. > > > > These HBAs have switched to use pci_alloc_irq_vectors(PCI_IRQ_AFFINITY) > > for automatic affinity assignment. > > > > Now 84676c1f21e8ff5(genirq/affinity: assign vectors to all possible CPUs) > > has been merged to V4.16-rc, and it is easy to allocate all offline CPUs > > for some irq vectors, this can't be avoided even though the allocation > > is improved. > > > > So all these drivers have to avoid to ask HBA to complete request in > > reply queue which hasn't online CPUs assigned, and HPSA has been broken > > with v4.15+: > > > > https://marc.info/?l=linux-kernel&m=151748144730409&w=2 > > > > This issue can be solved generically and easily via blk_mq(scsi_mq) multiple > > hw queue by mapping each reply queue into hctx, but one tricky thing is > > the HBA wide(instead of hw queue wide) tags. > > > > This patch is based on the following Hannes's patch: > > > > https://marc.info/?l=linux-block&m=149132580511346&w=2 > > > > One big difference with Hannes's is that this patch only makes the tags > > sbitmap > > and active_queues data structure HBA wide, and others are kept as NUMA > > locality, > > such as request, hctx, tags, ... > > > > The following patch will support global tags on null_blk, also the > > performance > > data is provided, no obvious performance loss is observed when the whole > > hw queue depth is same. > > > > Cc: Hannes Reinecke <h...@suse.de> > > Cc: Arun Easi <arun.e...@cavium.com> > > Cc: Omar Sandoval <osan...@fb.com>, > > Cc: "Martin K. Petersen" <martin.peter...@oracle.com>, > > Cc: James Bottomley <james.bottom...@hansenpartnership.com>, > > Cc: Christoph Hellwig <h...@lst.de>, > > Cc: Don Brace <don.br...@microsemi.com> > > Cc: Kashyap Desai <kashyap.de...@broadcom.com> > > Cc: Peter Rivera <peter.riv...@broadcom.com> > > Cc: Laurence Oberman <lober...@redhat.com> > > Cc: Mike Snitzer <snit...@redhat.com> > > Signed-off-by: Ming Lei <ming....@redhat.com> > > --- > > block/blk-mq-debugfs.c | 1 + > > block/blk-mq-sched.c | 2 +- > > block/blk-mq-tag.c | 23 ++++++++++++++++++----- > > block/blk-mq-tag.h | 5 ++++- > > block/blk-mq.c | 29 ++++++++++++++++++++++++----- > > block/blk-mq.h | 3 ++- > > include/linux/blk-mq.h | 2 ++ > > 7 files changed, 52 insertions(+), 13 deletions(-) > > > > diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c > > index 0dfafa4b655a..0f0fafe03f5d 100644 > > --- a/block/blk-mq-debugfs.c > > +++ b/block/blk-mq-debugfs.c > > @@ -206,6 +206,7 @@ static const char *const hctx_flag_name[] = { > > HCTX_FLAG_NAME(SHOULD_MERGE), > > HCTX_FLAG_NAME(TAG_SHARED), > > HCTX_FLAG_NAME(SG_MERGE), > > + HCTX_FLAG_NAME(GLOBAL_TAGS), > > HCTX_FLAG_NAME(BLOCKING), > > HCTX_FLAG_NAME(NO_SCHED), > > }; > > diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c > > index 55c0a745b427..191d4bc95f0e 100644 > > --- a/block/blk-mq-sched.c > > +++ b/block/blk-mq-sched.c > > @@ -495,7 +495,7 @@ static int blk_mq_sched_alloc_tags(struct request_queue > > *q, > > int ret; > > > > hctx->sched_tags = blk_mq_alloc_rq_map(set, hctx_idx, q->nr_requests, > > - set->reserved_tags); > > + set->reserved_tags, false); > > if (!hctx->sched_tags) > > return -ENOMEM; > > > > diff --git a/block/blk-mq-tag.c b/block/blk-mq-tag.c > > index 571797dc36cb..66377d09eaeb 100644 > > --- a/block/blk-mq-tag.c > > +++ b/block/blk-mq-tag.c > > @@ -379,9 +379,11 @@ static struct blk_mq_tags > > *blk_mq_init_bitmap_tags(struct blk_mq_tags *tags, > > return NULL; > > } > > > > -struct blk_mq_tags *blk_mq_init_tags(unsigned int total_tags, > > +struct blk_mq_tags *blk_mq_init_tags(struct blk_mq_tag_set *set, > > + unsigned int total_tags, > > unsigned int reserved_tags, > > - int node, int alloc_policy) > > + int node, int alloc_policy, > > + bool global_tag) > > { > > struct blk_mq_tags *tags; > > > > @@ -397,6 +399,14 @@ struct blk_mq_tags *blk_mq_init_tags(unsigned int > > total_tags, > > tags->nr_tags = total_tags; > > tags->nr_reserved_tags = reserved_tags; > > > > + WARN_ON(global_tag && !set->global_tags); > > + if (global_tag && set->global_tags) { > > + tags->bitmap_tags = set->global_tags->bitmap_tags; > > + tags->breserved_tags = set->global_tags->breserved_tags; > > + tags->active_queues = set->global_tags->active_queues; > > + tags->global_tags = true; > > + return tags; > > + } > > tags->bitmap_tags = &tags->__bitmap_tags; > > tags->breserved_tags = &tags->__breserved_tags; > > tags->active_queues = &tags->__active_queues; > Do we really need the 'global_tag' flag here? > Can't we just rely on the ->global_tags pointer to be set?
The same code is used for creating scheduler tags too, so the parameter of 'global_tag' has to be introduced. Thanks, Ming
