From c8158819d506a8aedeca53c52dfb709a0aabe011 Mon Sep 17 00:00:00 2001 From: Lin Ming Date: Sat, 23 Mar 2013 11:42:27 +0800 Subject: [PATCH] block: implement runtime pm strategy When a request is added: If device is suspended or is suspending and the request is not a PM request, resume the device. When the last request finishes: Call pm_runtime_mark_last_busy(). When pick a request: If device is resuming/suspending, then only PM request is allowed to go. The idea and API is designed by Alan Stern and described here: http://marc.info/?l=linux-scsi&m=133727953625963&w=2 Signed-off-by: Lin Ming Signed-off-by: Aaron Lu Acked-by: Alan Stern Signed-off-by: Jens Axboe --- block/blk-core.c | 39 +++++++++++++++++++++++++++++++++++++++ block/elevator.c | 26 ++++++++++++++++++++++++++ 2 files changed, 65 insertions(+) diff --git a/block/blk-core.c b/block/blk-core.c index 123d240132bf..441f3488a766 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1264,6 +1264,16 @@ void part_round_stats(int cpu, struct hd_struct *part) } EXPORT_SYMBOL_GPL(part_round_stats); +#ifdef CONFIG_PM_RUNTIME +static void blk_pm_put_request(struct request *rq) +{ + if (rq->q->dev && !(rq->cmd_flags & REQ_PM) && !--rq->q->nr_pending) + pm_runtime_mark_last_busy(rq->q->dev); +} +#else +static inline void blk_pm_put_request(struct request *rq) {} +#endif + /* * queue lock must be held */ @@ -1274,6 +1284,8 @@ void __blk_put_request(struct request_queue *q, struct request *req) if (unlikely(--req->ref_count)) return; + blk_pm_put_request(req); + elv_completed_request(q, req); /* this is a bio leak */ @@ -2053,6 +2065,28 @@ static void blk_account_io_done(struct request *req) } } +#ifdef CONFIG_PM_RUNTIME +/* + * Don't process normal requests when queue is suspended + * or in the process of suspending/resuming + */ +static struct request *blk_pm_peek_request(struct request_queue *q, + struct request *rq) +{ + if (q->dev && (q->rpm_status == RPM_SUSPENDED || + (q->rpm_status != RPM_ACTIVE && !(rq->cmd_flags & REQ_PM)))) + return NULL; + else + return rq; +} +#else +static inline struct request *blk_pm_peek_request(struct request_queue *q, + struct request *rq) +{ + return rq; +} +#endif + /** * blk_peek_request - peek at the top of a request queue * @q: request queue to peek at @@ -2075,6 +2109,11 @@ struct request *blk_peek_request(struct request_queue *q) int ret; while ((rq = __elv_next_request(q)) != NULL) { + + rq = blk_pm_peek_request(q, rq); + if (!rq) + break; + if (!(rq->cmd_flags & REQ_STARTED)) { /* * This is the first time the device driver diff --git a/block/elevator.c b/block/elevator.c index a0ffdd943c98..eba5b04c29b1 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -34,6 +34,7 @@ #include #include #include +#include #include @@ -536,6 +537,27 @@ void elv_bio_merged(struct request_queue *q, struct request *rq, e->type->ops.elevator_bio_merged_fn(q, rq, bio); } +#ifdef CONFIG_PM_RUNTIME +static void blk_pm_requeue_request(struct request *rq) +{ + if (rq->q->dev && !(rq->cmd_flags & REQ_PM)) + rq->q->nr_pending--; +} + +static void blk_pm_add_request(struct request_queue *q, struct request *rq) +{ + if (q->dev && !(rq->cmd_flags & REQ_PM) && q->nr_pending++ == 0 && + (q->rpm_status == RPM_SUSPENDED || q->rpm_status == RPM_SUSPENDING)) + pm_request_resume(q->dev); +} +#else +static inline void blk_pm_requeue_request(struct request *rq) {} +static inline void blk_pm_add_request(struct request_queue *q, + struct request *rq) +{ +} +#endif + void elv_requeue_request(struct request_queue *q, struct request *rq) { /* @@ -550,6 +572,8 @@ void elv_requeue_request(struct request_queue *q, struct request *rq) rq->cmd_flags &= ~REQ_STARTED; + blk_pm_requeue_request(rq); + __elv_add_request(q, rq, ELEVATOR_INSERT_REQUEUE); } @@ -572,6 +596,8 @@ void __elv_add_request(struct request_queue *q, struct request *rq, int where) { trace_block_rq_insert(q, rq); + blk_pm_add_request(q, rq); + rq->q = q; if (rq->cmd_flags & REQ_SOFTBARRIER) { -- 2.39.5