| Message ID | 20170523114736.12026-3-ming.lei@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, May 23, 2017 at 07:47:36PM +0800, Ming Lei wrote: > Because what the per-sw-queue bio merge does is basically same with > scheduler's .bio_merge(), this patch makes per-sw-queue bio merge > as the default .bio_merge if no scheduler is used or io scheduler > doesn't provide .bio_merge(). > > Signed-off-by: Ming Lei <ming.lei@redhat.com> > --- > block/blk-mq-sched.c | 62 +++++++++++++++++++++++++++++++++++++++++++++---- > block/blk-mq-sched.h | 4 +--- > block/blk-mq.c | 65 ---------------------------------------------------- > 3 files changed, 58 insertions(+), 73 deletions(-) > > diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c > index 1f5b692526ae..c4e2afb9d12d 100644 > --- a/block/blk-mq-sched.c > +++ b/block/blk-mq-sched.c > @@ -221,19 +221,71 @@ bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio, > } > EXPORT_SYMBOL_GPL(blk_mq_sched_try_merge); > > +/* > + * Reverse check our software queue for entries that we could potentially > + * merge with. Currently includes a hand-wavy stop count of 8, to not spend > + * too much time checking for merges. > + */ > +static bool blk_mq_attempt_merge(struct request_queue *q, > + struct blk_mq_ctx *ctx, struct bio *bio) > +{ > + struct request *rq; > + int checked = 8; > + > + list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) { > + bool merged = false; > + > + if (!checked--) > + break; > + > + if (!blk_rq_merge_ok(rq, bio)) > + continue; > + > + switch (blk_try_merge(rq, bio)) { > + case ELEVATOR_BACK_MERGE: > + if (blk_mq_sched_allow_merge(q, rq, bio)) > + merged = bio_attempt_back_merge(q, rq, bio); > + break; > + case ELEVATOR_FRONT_MERGE: > + if (blk_mq_sched_allow_merge(q, rq, bio)) > + merged = bio_attempt_front_merge(q, rq, bio); > + break; > + case ELEVATOR_DISCARD_MERGE: > + merged = bio_attempt_discard_merge(q, rq, bio); > + break; > + default: > + continue; > + } > + > + if (merged) > + ctx->rq_merged++; > + return merged; > + } > + > + return false; > +} > + > bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio) > { > struct elevator_queue *e = q->elevator; > + struct blk_mq_ctx *ctx = blk_mq_get_ctx(q); > + struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu); > + bool ret = false; > > + if (e && e->type->ops.mq.bio_merge) { > blk_mq_put_ctx(ctx); > return e->type->ops.mq.bio_merge(hctx, bio); > } > > + if (hctx->flags & BLK_MQ_F_SHOULD_MERGE) { > + /* default per sw-queue merge */ > + spin_lock(&ctx->lock); > + ret = blk_mq_attempt_merge(q, ctx, bio); > + spin_unlock(&ctx->lock); > + } > + > + blk_mq_put_ctx(ctx); > + return ret; I'd rather move __blk_mq_sched_bio_merge/blk_mq_sched_bio_merge into blk-mq.c (and dropping the sched in the name) rather than moving blk_mq_attempt_merge out. But except that this looks fine to me.
On Wed, May 24, 2017 at 02:58:43AM -0700, Christoph Hellwig wrote: > On Tue, May 23, 2017 at 07:47:36PM +0800, Ming Lei wrote: > > Because what the per-sw-queue bio merge does is basically same with > > scheduler's .bio_merge(), this patch makes per-sw-queue bio merge > > as the default .bio_merge if no scheduler is used or io scheduler > > doesn't provide .bio_merge(). > > > > Signed-off-by: Ming Lei <ming.lei@redhat.com> > > --- > > block/blk-mq-sched.c | 62 +++++++++++++++++++++++++++++++++++++++++++++---- > > block/blk-mq-sched.h | 4 +--- > > block/blk-mq.c | 65 ---------------------------------------------------- > > 3 files changed, 58 insertions(+), 73 deletions(-) > > > > diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c > > index 1f5b692526ae..c4e2afb9d12d 100644 > > --- a/block/blk-mq-sched.c > > +++ b/block/blk-mq-sched.c > > @@ -221,19 +221,71 @@ bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio, > > } > > EXPORT_SYMBOL_GPL(blk_mq_sched_try_merge); > > > > +/* > > + * Reverse check our software queue for entries that we could potentially > > + * merge with. Currently includes a hand-wavy stop count of 8, to not spend > > + * too much time checking for merges. > > + */ > > +static bool blk_mq_attempt_merge(struct request_queue *q, > > + struct blk_mq_ctx *ctx, struct bio *bio) > > +{ > > + struct request *rq; > > + int checked = 8; > > + > > + list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) { > > + bool merged = false; > > + > > + if (!checked--) > > + break; > > + > > + if (!blk_rq_merge_ok(rq, bio)) > > + continue; > > + > > + switch (blk_try_merge(rq, bio)) { > > + case ELEVATOR_BACK_MERGE: > > + if (blk_mq_sched_allow_merge(q, rq, bio)) > > + merged = bio_attempt_back_merge(q, rq, bio); > > + break; > > + case ELEVATOR_FRONT_MERGE: > > + if (blk_mq_sched_allow_merge(q, rq, bio)) > > + merged = bio_attempt_front_merge(q, rq, bio); > > + break; > > + case ELEVATOR_DISCARD_MERGE: > > + merged = bio_attempt_discard_merge(q, rq, bio); > > + break; > > + default: > > + continue; > > + } > > + > > + if (merged) > > + ctx->rq_merged++; > > + return merged; > > + } > > + > > + return false; > > +} > > + > > bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio) > > { > > struct elevator_queue *e = q->elevator; > > + struct blk_mq_ctx *ctx = blk_mq_get_ctx(q); > > + struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu); > > + bool ret = false; > > > > + if (e && e->type->ops.mq.bio_merge) { > > blk_mq_put_ctx(ctx); > > return e->type->ops.mq.bio_merge(hctx, bio); > > } > > > > + if (hctx->flags & BLK_MQ_F_SHOULD_MERGE) { > > + /* default per sw-queue merge */ > > + spin_lock(&ctx->lock); > > + ret = blk_mq_attempt_merge(q, ctx, bio); > > + spin_unlock(&ctx->lock); > > + } > > + > > + blk_mq_put_ctx(ctx); > > + return ret; > > I'd rather move __blk_mq_sched_bio_merge/blk_mq_sched_bio_merge into > blk-mq.c (and dropping the sched in the name) rather than moving > blk_mq_attempt_merge out. OK, will do that in V3. Thanks, Ming
On Wed, May 24, 2017 at 02:58:43AM -0700, Christoph Hellwig wrote: > On Tue, May 23, 2017 at 07:47:36PM +0800, Ming Lei wrote: > > Because what the per-sw-queue bio merge does is basically same with > > scheduler's .bio_merge(), this patch makes per-sw-queue bio merge > > as the default .bio_merge if no scheduler is used or io scheduler > > doesn't provide .bio_merge(). > > > > Signed-off-by: Ming Lei <ming.lei@redhat.com> > > --- > > block/blk-mq-sched.c | 62 +++++++++++++++++++++++++++++++++++++++++++++---- > > block/blk-mq-sched.h | 4 +--- > > block/blk-mq.c | 65 ---------------------------------------------------- > > 3 files changed, 58 insertions(+), 73 deletions(-) > > > > diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c > > index 1f5b692526ae..c4e2afb9d12d 100644 > > --- a/block/blk-mq-sched.c > > +++ b/block/blk-mq-sched.c > > @@ -221,19 +221,71 @@ bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio, > > } > > EXPORT_SYMBOL_GPL(blk_mq_sched_try_merge); > > > > +/* > > + * Reverse check our software queue for entries that we could potentially > > + * merge with. Currently includes a hand-wavy stop count of 8, to not spend > > + * too much time checking for merges. > > + */ > > +static bool blk_mq_attempt_merge(struct request_queue *q, > > + struct blk_mq_ctx *ctx, struct bio *bio) > > +{ > > + struct request *rq; > > + int checked = 8; > > + > > + list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) { > > + bool merged = false; > > + > > + if (!checked--) > > + break; > > + > > + if (!blk_rq_merge_ok(rq, bio)) > > + continue; > > + > > + switch (blk_try_merge(rq, bio)) { > > + case ELEVATOR_BACK_MERGE: > > + if (blk_mq_sched_allow_merge(q, rq, bio)) > > + merged = bio_attempt_back_merge(q, rq, bio); > > + break; > > + case ELEVATOR_FRONT_MERGE: > > + if (blk_mq_sched_allow_merge(q, rq, bio)) > > + merged = bio_attempt_front_merge(q, rq, bio); > > + break; > > + case ELEVATOR_DISCARD_MERGE: > > + merged = bio_attempt_discard_merge(q, rq, bio); > > + break; > > + default: > > + continue; > > + } > > + > > + if (merged) > > + ctx->rq_merged++; > > + return merged; > > + } > > + > > + return false; > > +} > > + > > bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio) > > { > > struct elevator_queue *e = q->elevator; > > + struct blk_mq_ctx *ctx = blk_mq_get_ctx(q); > > + struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu); > > + bool ret = false; > > > > + if (e && e->type->ops.mq.bio_merge) { > > blk_mq_put_ctx(ctx); > > return e->type->ops.mq.bio_merge(hctx, bio); > > } > > > > + if (hctx->flags & BLK_MQ_F_SHOULD_MERGE) { > > + /* default per sw-queue merge */ > > + spin_lock(&ctx->lock); > > + ret = blk_mq_attempt_merge(q, ctx, bio); > > + spin_unlock(&ctx->lock); > > + } > > + > > + blk_mq_put_ctx(ctx); > > + return ret; > > I'd rather move __blk_mq_sched_bio_merge/blk_mq_sched_bio_merge into > blk-mq.c (and dropping the sched in the name) rather than moving > blk_mq_attempt_merge out. Looked at the code further, maybe it isn't good to move __blk_mq_sched_bio_merge() to blk-mq.c because the stuff of 'e && e->type->ops.mq.*' has never been put into blk-mq.c. So how about not moving blk_mq_attempt_merge() and just define it as global? Thanks, Ming
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index 1f5b692526ae..c4e2afb9d12d 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -221,19 +221,71 @@ bool blk_mq_sched_try_merge(struct request_queue *q, struct bio *bio, } EXPORT_SYMBOL_GPL(blk_mq_sched_try_merge); +/* + * Reverse check our software queue for entries that we could potentially + * merge with. Currently includes a hand-wavy stop count of 8, to not spend + * too much time checking for merges. + */ +static bool blk_mq_attempt_merge(struct request_queue *q, + struct blk_mq_ctx *ctx, struct bio *bio) +{ + struct request *rq; + int checked = 8; + + list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) { + bool merged = false; + + if (!checked--) + break; + + if (!blk_rq_merge_ok(rq, bio)) + continue; + + switch (blk_try_merge(rq, bio)) { + case ELEVATOR_BACK_MERGE: + if (blk_mq_sched_allow_merge(q, rq, bio)) + merged = bio_attempt_back_merge(q, rq, bio); + break; + case ELEVATOR_FRONT_MERGE: + if (blk_mq_sched_allow_merge(q, rq, bio)) + merged = bio_attempt_front_merge(q, rq, bio); + break; + case ELEVATOR_DISCARD_MERGE: + merged = bio_attempt_discard_merge(q, rq, bio); + break; + default: + continue; + } + + if (merged) + ctx->rq_merged++; + return merged; + } + + return false; +} + bool __blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio) { struct elevator_queue *e = q->elevator; + struct blk_mq_ctx *ctx = blk_mq_get_ctx(q); + struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu); + bool ret = false; - if (e->type->ops.mq.bio_merge) { - struct blk_mq_ctx *ctx = blk_mq_get_ctx(q); - struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu); - + if (e && e->type->ops.mq.bio_merge) { blk_mq_put_ctx(ctx); return e->type->ops.mq.bio_merge(hctx, bio); } - return false; + if (hctx->flags & BLK_MQ_F_SHOULD_MERGE) { + /* default per sw-queue merge */ + spin_lock(&ctx->lock); + ret = blk_mq_attempt_merge(q, ctx, bio); + spin_unlock(&ctx->lock); + } + + blk_mq_put_ctx(ctx); + return ret; } bool blk_mq_sched_try_insert_merge(struct request_queue *q, struct request *rq) diff --git a/block/blk-mq-sched.h b/block/blk-mq-sched.h index edafb5383b7b..b87e5be5db8c 100644 --- a/block/blk-mq-sched.h +++ b/block/blk-mq-sched.h @@ -38,9 +38,7 @@ int blk_mq_sched_init(struct request_queue *q); static inline bool blk_mq_sched_bio_merge(struct request_queue *q, struct bio *bio) { - struct elevator_queue *e = q->elevator; - - if (!e || blk_queue_nomerges(q) || !bio_mergeable(bio)) + if (blk_queue_nomerges(q) || !bio_mergeable(bio)) return false; return __blk_mq_sched_bio_merge(q, bio); diff --git a/block/blk-mq.c b/block/blk-mq.c index b7ca64ef15e8..9aec650aea2a 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -772,50 +772,6 @@ static void blk_mq_timeout_work(struct work_struct *work) blk_queue_exit(q); } -/* - * Reverse check our software queue for entries that we could potentially - * merge with. Currently includes a hand-wavy stop count of 8, to not spend - * too much time checking for merges. - */ -static bool blk_mq_attempt_merge(struct request_queue *q, - struct blk_mq_ctx *ctx, struct bio *bio) -{ - struct request *rq; - int checked = 8; - - list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) { - bool merged = false; - - if (!checked--) - break; - - if (!blk_rq_merge_ok(rq, bio)) - continue; - - switch (blk_try_merge(rq, bio)) { - case ELEVATOR_BACK_MERGE: - if (blk_mq_sched_allow_merge(q, rq, bio)) - merged = bio_attempt_back_merge(q, rq, bio); - break; - case ELEVATOR_FRONT_MERGE: - if (blk_mq_sched_allow_merge(q, rq, bio)) - merged = bio_attempt_front_merge(q, rq, bio); - break; - case ELEVATOR_DISCARD_MERGE: - merged = bio_attempt_discard_merge(q, rq, bio); - break; - default: - continue; - } - - if (merged) - ctx->rq_merged++; - return merged; - } - - return false; -} - struct flush_busy_ctx_data { struct blk_mq_hw_ctx *hctx; struct list_head *list; @@ -1446,24 +1402,6 @@ static inline bool hctx_allow_merges(struct blk_mq_hw_ctx *hctx) !blk_queue_nomerges(hctx->queue); } -/* attempt to merge bio into current sw queue */ -static inline bool blk_mq_merge_bio(struct request_queue *q, struct bio *bio) -{ - bool ret = false; - struct blk_mq_ctx *ctx = blk_mq_get_ctx(q); - struct blk_mq_hw_ctx *hctx = blk_mq_map_queue(q, ctx->cpu); - - if (!hctx_allow_merges(hctx) || !bio_mergeable(bio)) - goto exit; - - spin_lock(&ctx->lock); - ret = blk_mq_attempt_merge(q, ctx, bio); - spin_unlock(&ctx->lock); -exit: - blk_mq_put_ctx(ctx); - return ret; -} - static inline void blk_mq_queue_io(struct blk_mq_hw_ctx *hctx, struct blk_mq_ctx *ctx, struct request *rq) @@ -1569,9 +1507,6 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio) if (blk_mq_sched_bio_merge(q, bio)) return BLK_QC_T_NONE; - if (blk_mq_merge_bio(q, bio)) - return BLK_QC_T_NONE; - wb_acct = wbt_wait(q->rq_wb, bio, NULL); trace_block_getrq(q, bio, bio->bi_opf);
Because what the per-sw-queue bio merge does is basically same with scheduler's .bio_merge(), this patch makes per-sw-queue bio merge as the default .bio_merge if no scheduler is used or io scheduler doesn't provide .bio_merge(). Signed-off-by: Ming Lei <ming.lei@redhat.com> --- block/blk-mq-sched.c | 62 +++++++++++++++++++++++++++++++++++++++++++++---- block/blk-mq-sched.h | 4 +--- block/blk-mq.c | 65 ---------------------------------------------------- 3 files changed, 58 insertions(+), 73 deletions(-)