From d9c97833179036408e53ef5f3f5c7eaf781769bc Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 12 Apr 2011 10:06:33 +0200 Subject: block: remove block_unplug_timer() trace point We no longer have an unplug timer running, so no point in keeping the trace point. Signed-off-by: Jens Axboe --- include/trace/events/block.h | 14 -------------- 1 file changed, 14 deletions(-) (limited to 'include/trace/events/block.h') diff --git a/include/trace/events/block.h b/include/trace/events/block.h index 78f18adb49c..43a985390bb 100644 --- a/include/trace/events/block.h +++ b/include/trace/events/block.h @@ -418,20 +418,6 @@ DECLARE_EVENT_CLASS(block_unplug, TP_printk("[%s] %d", __entry->comm, __entry->nr_rq) ); -/** - * block_unplug_timer - timed release of operations requests in queue to device driver - * @q: request queue to unplug - * - * Unplug the request queue @q because a timer expired and allow block - * operation requests to be sent to the device driver. - */ -DEFINE_EVENT(block_unplug, block_unplug_timer, - - TP_PROTO(struct request_queue *q), - - TP_ARGS(q) -); - /** * block_unplug_io - release of operations requests in request queue * @q: request queue to unplug -- cgit v1.2.3-70-g09d2 From 94b5eb28b41cc79d9713696e0005ae167b5afd1b Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Tue, 12 Apr 2011 10:12:19 +0200 Subject: block: fixup block IO unplug trace call It was removed with the on-stack plugging, readd it and track the depth of requests added when flushing the plug. Signed-off-by: Jens Axboe --- block/blk-core.c | 15 +++++++++++++-- include/trace/events/block.h | 11 ++++++----- kernel/trace/blktrace.c | 6 +++--- 3 files changed, 22 insertions(+), 10 deletions(-) (limited to 'include/trace/events/block.h') diff --git a/block/blk-core.c b/block/blk-core.c index eeaca0998df..d20ce1e849c 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -2668,12 +2668,19 @@ static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b) return !(rqa->q <= rqb->q); } +static void queue_unplugged(struct request_queue *q, unsigned int depth) +{ + trace_block_unplug_io(q, depth); + __blk_run_queue(q, false); +} + static void flush_plug_list(struct blk_plug *plug) { struct request_queue *q; unsigned long flags; struct request *rq; LIST_HEAD(list); + unsigned int depth; BUG_ON(plug->magic != PLUG_MAGIC); @@ -2688,6 +2695,7 @@ static void flush_plug_list(struct blk_plug *plug) } q = NULL; + depth = 0; local_irq_save(flags); while (!list_empty(&list)) { rq = list_entry_rq(list.next); @@ -2696,10 +2704,11 @@ static void flush_plug_list(struct blk_plug *plug) BUG_ON(!rq->q); if (rq->q != q) { if (q) { - __blk_run_queue(q, false); + queue_unplugged(q, depth); spin_unlock(q->queue_lock); } q = rq->q; + depth = 0; spin_lock(q->queue_lock); } rq->cmd_flags &= ~REQ_ON_PLUG; @@ -2711,10 +2720,12 @@ static void flush_plug_list(struct blk_plug *plug) __elv_add_request(q, rq, ELEVATOR_INSERT_FLUSH); else __elv_add_request(q, rq, ELEVATOR_INSERT_SORT_MERGE); + + depth++; } if (q) { - __blk_run_queue(q, false); + queue_unplugged(q, depth); spin_unlock(q->queue_lock); } diff --git a/include/trace/events/block.h b/include/trace/events/block.h index 43a985390bb..006e60b5830 100644 --- a/include/trace/events/block.h +++ b/include/trace/events/block.h @@ -401,9 +401,9 @@ TRACE_EVENT(block_plug, DECLARE_EVENT_CLASS(block_unplug, - TP_PROTO(struct request_queue *q), + TP_PROTO(struct request_queue *q, unsigned int depth), - TP_ARGS(q), + TP_ARGS(q, depth), TP_STRUCT__entry( __field( int, nr_rq ) @@ -411,7 +411,7 @@ DECLARE_EVENT_CLASS(block_unplug, ), TP_fast_assign( - __entry->nr_rq = q->rq.count[READ] + q->rq.count[WRITE]; + __entry->nr_rq = depth; memcpy(__entry->comm, current->comm, TASK_COMM_LEN); ), @@ -421,15 +421,16 @@ DECLARE_EVENT_CLASS(block_unplug, /** * block_unplug_io - release of operations requests in request queue * @q: request queue to unplug + * @depth: number of requests just added to the queue * * Unplug request queue @q because device driver is scheduled to work * on elements in the request queue. */ DEFINE_EVENT(block_unplug, block_unplug_io, - TP_PROTO(struct request_queue *q), + TP_PROTO(struct request_queue *q, unsigned int depth), - TP_ARGS(q) + TP_ARGS(q, depth) ); /** diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 824708cbfb7..3e3970d53d1 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -850,13 +850,13 @@ static void blk_add_trace_plug(void *ignore, struct request_queue *q) __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); } -static void blk_add_trace_unplug_io(void *ignore, struct request_queue *q) +static void blk_add_trace_unplug_io(void *ignore, struct request_queue *q, + unsigned int depth) { struct blk_trace *bt = q->blk_trace; if (bt) { - unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE]; - __be64 rpdu = cpu_to_be64(pdu); + __be64 rpdu = cpu_to_be64(depth); __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0, sizeof(rpdu), &rpdu); -- cgit v1.2.3-70-g09d2 From 49cac01e1fa74174d72adb0e872504a7fefd7c01 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sat, 16 Apr 2011 13:51:05 +0200 Subject: block: make unplug timer trace event correspond to the schedule() unplug It's a pretty close match to what we had before - the timer triggering would mean that nobody unplugged the plug in due time, in the new scheme this matches very closely what the schedule() unplug now is. It's essentially the difference between an explicit unplug (IO unplug) or an implicit unplug (timer unplug, we scheduled with pending IO queued). Signed-off-by: Jens Axboe --- block/blk-core.c | 18 ++++++++++++------ include/trace/events/block.h | 13 +++++++------ kernel/trace/blktrace.c | 18 ++++++++++++------ 3 files changed, 31 insertions(+), 18 deletions(-) (limited to 'include/trace/events/block.h') diff --git a/block/blk-core.c b/block/blk-core.c index 3c812107250..78b7b0cb721 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -2662,17 +2662,23 @@ static int plug_rq_cmp(void *priv, struct list_head *a, struct list_head *b) return !(rqa->q <= rqb->q); } +/* + * If 'from_schedule' is true, then postpone the dispatch of requests + * until a safe kblockd context. We due this to avoid accidental big + * additional stack usage in driver dispatch, in places where the originally + * plugger did not intend it. + */ static void queue_unplugged(struct request_queue *q, unsigned int depth, - bool force_kblockd) + bool from_schedule) { - trace_block_unplug_io(q, depth); - __blk_run_queue(q, force_kblockd); + trace_block_unplug(q, depth, !from_schedule); + __blk_run_queue(q, from_schedule); if (q->unplugged_fn) q->unplugged_fn(q); } -void blk_flush_plug_list(struct blk_plug *plug, bool force_kblockd) +void blk_flush_plug_list(struct blk_plug *plug, bool from_schedule) { struct request_queue *q; unsigned long flags; @@ -2707,7 +2713,7 @@ void blk_flush_plug_list(struct blk_plug *plug, bool force_kblockd) BUG_ON(!rq->q); if (rq->q != q) { if (q) { - queue_unplugged(q, depth, force_kblockd); + queue_unplugged(q, depth, from_schedule); spin_unlock(q->queue_lock); } q = rq->q; @@ -2728,7 +2734,7 @@ void blk_flush_plug_list(struct blk_plug *plug, bool force_kblockd) } if (q) { - queue_unplugged(q, depth, force_kblockd); + queue_unplugged(q, depth, from_schedule); spin_unlock(q->queue_lock); } diff --git a/include/trace/events/block.h b/include/trace/events/block.h index 006e60b5830..bf366547da2 100644 --- a/include/trace/events/block.h +++ b/include/trace/events/block.h @@ -401,9 +401,9 @@ TRACE_EVENT(block_plug, DECLARE_EVENT_CLASS(block_unplug, - TP_PROTO(struct request_queue *q, unsigned int depth), + TP_PROTO(struct request_queue *q, unsigned int depth, bool explicit), - TP_ARGS(q, depth), + TP_ARGS(q, depth, explicit), TP_STRUCT__entry( __field( int, nr_rq ) @@ -419,18 +419,19 @@ DECLARE_EVENT_CLASS(block_unplug, ); /** - * block_unplug_io - release of operations requests in request queue + * block_unplug - release of operations requests in request queue * @q: request queue to unplug * @depth: number of requests just added to the queue + * @explicit: whether this was an explicit unplug, or one from schedule() * * Unplug request queue @q because device driver is scheduled to work * on elements in the request queue. */ -DEFINE_EVENT(block_unplug, block_unplug_io, +DEFINE_EVENT(block_unplug, block_unplug, - TP_PROTO(struct request_queue *q, unsigned int depth), + TP_PROTO(struct request_queue *q, unsigned int depth, bool explicit), - TP_ARGS(q, depth) + TP_ARGS(q, depth, explicit) ); /** diff --git a/kernel/trace/blktrace.c b/kernel/trace/blktrace.c index 3e3970d53d1..6957aa298df 100644 --- a/kernel/trace/blktrace.c +++ b/kernel/trace/blktrace.c @@ -850,16 +850,21 @@ static void blk_add_trace_plug(void *ignore, struct request_queue *q) __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL); } -static void blk_add_trace_unplug_io(void *ignore, struct request_queue *q, - unsigned int depth) +static void blk_add_trace_unplug(void *ignore, struct request_queue *q, + unsigned int depth, bool explicit) { struct blk_trace *bt = q->blk_trace; if (bt) { __be64 rpdu = cpu_to_be64(depth); + u32 what; - __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0, - sizeof(rpdu), &rpdu); + if (explicit) + what = BLK_TA_UNPLUG_IO; + else + what = BLK_TA_UNPLUG_TIMER; + + __blk_add_trace(bt, 0, 0, 0, what, 0, sizeof(rpdu), &rpdu); } } @@ -1002,7 +1007,7 @@ static void blk_register_tracepoints(void) WARN_ON(ret); ret = register_trace_block_plug(blk_add_trace_plug, NULL); WARN_ON(ret); - ret = register_trace_block_unplug_io(blk_add_trace_unplug_io, NULL); + ret = register_trace_block_unplug(blk_add_trace_unplug, NULL); WARN_ON(ret); ret = register_trace_block_split(blk_add_trace_split, NULL); WARN_ON(ret); @@ -1017,7 +1022,7 @@ static void blk_unregister_tracepoints(void) unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL); unregister_trace_block_bio_remap(blk_add_trace_bio_remap, NULL); unregister_trace_block_split(blk_add_trace_split, NULL); - unregister_trace_block_unplug_io(blk_add_trace_unplug_io, NULL); + unregister_trace_block_unplug(blk_add_trace_unplug, NULL); unregister_trace_block_plug(blk_add_trace_plug, NULL); unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL); unregister_trace_block_getrq(blk_add_trace_getrq, NULL); @@ -1332,6 +1337,7 @@ static const struct { [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error }, [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug }, [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug }, + [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug }, [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic }, [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split }, [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic }, -- cgit v1.2.3-70-g09d2