| Message ID | 1533716548-1645-1-git-send-email-jianchao.w.wang@oracle.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | blk-mq: count the hctx as active before allocate tag | expand |
On Wed, Aug 8, 2018 at 4:22 PM, Jianchao Wang <jianchao.w.wang@oracle.com> wrote: > Currently, we count the hctx as active after allocate tag > successfully. The other shared-tags users could exhaust the tags > and starve a non-active and waiting-tag hctx. Count the hctx as > active before try to allocate tag to fix this. This patch looks fine. > > Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> > --- > block/blk-mq.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/block/blk-mq.c b/block/blk-mq.c > index ae44e85..acd40eb 100644 > --- a/block/blk-mq.c > +++ b/block/blk-mq.c > @@ -369,6 +369,8 @@ static struct request *blk_mq_get_request(struct request_queue *q, > e->type->ops.mq.limit_depth(op, data); > } > > + blk_mq_tag_busy(data.hctx); > + blk_mq_tag_busy is only required for driver tag. Thanks, Ming Lei
On 08/08/2018 05:24 PM, Ming Lei wrote: > On Wed, Aug 8, 2018 at 4:22 PM, Jianchao Wang > <jianchao.w.wang@oracle.com> wrote: >> Currently, we count the hctx as active after allocate tag >> successfully. The other shared-tags users could exhaust the tags >> and starve a non-active and waiting-tag hctx. Count the hctx as >> active before try to allocate tag to fix this. > > This patch looks fine. > >> >> Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> >> --- >> block/blk-mq.c | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/block/blk-mq.c b/block/blk-mq.c >> index ae44e85..acd40eb 100644 >> --- a/block/blk-mq.c >> +++ b/block/blk-mq.c >> @@ -369,6 +369,8 @@ static struct request *blk_mq_get_request(struct request_queue *q, >> e->type->ops.mq.limit_depth(op, data); >> } >> >> + blk_mq_tag_busy(data.hctx); >> + > > blk_mq_tag_busy is only required for driver tag. > Yes, I will change it and post the V2. Thanks Jianchao
diff --git a/block/blk-mq.c b/block/blk-mq.c index ae44e85..acd40eb 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -369,6 +369,8 @@ static struct request *blk_mq_get_request(struct request_queue *q, e->type->ops.mq.limit_depth(op, data); } + blk_mq_tag_busy(data.hctx); + tag = blk_mq_get_tag(data); if (tag == BLK_MQ_TAG_FAIL) { if (put_ctx_on_error) { @@ -972,6 +974,7 @@ bool blk_mq_get_driver_tag(struct request *rq, struct blk_mq_hw_ctx **hctx, .hctx = blk_mq_map_queue(rq->q, rq->mq_ctx->cpu), .flags = wait ? 0 : BLK_MQ_REQ_NOWAIT, }; + bool shared; might_sleep_if(wait); @@ -981,9 +984,10 @@ bool blk_mq_get_driver_tag(struct request *rq, struct blk_mq_hw_ctx **hctx, if (blk_mq_tag_is_reserved(data.hctx->sched_tags, rq->internal_tag)) data.flags |= BLK_MQ_REQ_RESERVED; + shared = blk_mq_tag_busy(data.hctx); rq->tag = blk_mq_get_tag(&data); if (rq->tag >= 0) { - if (blk_mq_tag_busy(data.hctx)) { + if (shared) { rq->rq_flags |= RQF_MQ_INFLIGHT; atomic_inc(&data.hctx->nr_active); }
Currently, we count the hctx as active after allocate tag successfully. The other shared-tags users could exhaust the tags and starve a non-active and waiting-tag hctx. Count the hctx as active before try to allocate tag to fix this. Signed-off-by: Jianchao Wang <jianchao.w.wang@oracle.com> --- block/blk-mq.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)