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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 <ming.m.lin@intel.com>
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
master
Lin Ming 9 years ago
committed by Jens Axboe
parent
commit
c8158819d5
  1. 39
      block/blk-core.c
  2. 26
      block/elevator.c

39
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

26
block/elevator.c

@ -34,6 +34,7 @@
#include <linux/blktrace_api.h>
#include <linux/hash.h>
#include <linux/uaccess.h>
#include <linux/pm_runtime.h>
#include <trace/events/block.h>
@ -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) {

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