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Commit 84c7afce authored by Omar Sandoval's avatar Omar Sandoval Committed by Jens Axboe
Browse files

block: use ktime_get_ns() instead of sched_clock() for cfq and bfq 



cfq and bfq have some internal fields that use sched_clock() which can
trivially use ktime_get_ns() instead. Their timestamp fields in struct
request can also use ktime_get_ns(), which resolves the 8 year old
comment added by commit 28f4197e ("block: disable preemption before
using sched_clock()").

Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 544ccc8d

block/bfq-cgroup.c

+20 −20
Original line number Diff line number Diff line
@@ -55,13 +55,13 @@ BFQG_FLAG_FNS(empty) 
/* This should be called with the scheduler lock held. */

static void bfqg_stats_update_group_wait_time(struct bfqg_stats *stats)

{

	unsigned long long now;

	u64 now;



	if (!bfqg_stats_waiting(stats))

		return;



	now = sched_clock();

	if (time_after64(now, stats->start_group_wait_time))

	now = ktime_get_ns();

	if (now > stats->start_group_wait_time)

		blkg_stat_add(&stats->group_wait_time,

			      now - stats->start_group_wait_time);

	bfqg_stats_clear_waiting(stats);
@@ -77,20 +77,20 @@ static void bfqg_stats_set_start_group_wait_time(struct bfq_group *bfqg, 
		return;

	if (bfqg == curr_bfqg)

		return;

	stats->start_group_wait_time = sched_clock();

	stats->start_group_wait_time = ktime_get_ns();

	bfqg_stats_mark_waiting(stats);

}



/* This should be called with the scheduler lock held. */

static void bfqg_stats_end_empty_time(struct bfqg_stats *stats)

{

	unsigned long long now;

	u64 now;



	if (!bfqg_stats_empty(stats))

		return;



	now = sched_clock();

	if (time_after64(now, stats->start_empty_time))

	now = ktime_get_ns();

	if (now > stats->start_empty_time)

		blkg_stat_add(&stats->empty_time,

			      now - stats->start_empty_time);

	bfqg_stats_clear_empty(stats);
@@ -116,7 +116,7 @@ void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg) 
	if (bfqg_stats_empty(stats))

		return;



	stats->start_empty_time = sched_clock();

	stats->start_empty_time = ktime_get_ns();

	bfqg_stats_mark_empty(stats);

}
@@ -125,9 +125,9 @@ void bfqg_stats_update_idle_time(struct bfq_group *bfqg) 
	struct bfqg_stats *stats = &bfqg->stats;



	if (bfqg_stats_idling(stats)) {

		unsigned long long now = sched_clock();

		u64 now = ktime_get_ns();



		if (time_after64(now, stats->start_idle_time))

		if (now > stats->start_idle_time)

			blkg_stat_add(&stats->idle_time,

				      now - stats->start_idle_time);

		bfqg_stats_clear_idling(stats);
@@ -138,7 +138,7 @@ void bfqg_stats_set_start_idle_time(struct bfq_group *bfqg) 
{

	struct bfqg_stats *stats = &bfqg->stats;



	stats->start_idle_time = sched_clock();

	stats->start_idle_time = ktime_get_ns();

	bfqg_stats_mark_idling(stats);

}
@@ -171,18 +171,18 @@ void bfqg_stats_update_io_merged(struct bfq_group *bfqg, unsigned int op) 
	blkg_rwstat_add(&bfqg->stats.merged, op, 1);

}



void bfqg_stats_update_completion(struct bfq_group *bfqg, uint64_t start_time,

				  uint64_t io_start_time, unsigned int op)

void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns,

				  u64 io_start_time_ns, unsigned int op)

{

	struct bfqg_stats *stats = &bfqg->stats;

	unsigned long long now = sched_clock();

	u64 now = ktime_get_ns();



	if (time_after64(now, io_start_time))

	if (now > io_start_time_ns)

		blkg_rwstat_add(&stats->service_time, op,

				now - io_start_time);

	if (time_after64(io_start_time, start_time))

				now - io_start_time_ns);

	if (io_start_time_ns > start_time_ns)

		blkg_rwstat_add(&stats->wait_time, op,

				io_start_time - start_time);

				io_start_time_ns - start_time_ns);

}



#else /* CONFIG_BFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
@@ -191,8 +191,8 @@ void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq, 
			      unsigned int op) { }

void bfqg_stats_update_io_remove(struct bfq_group *bfqg, unsigned int op) { }

void bfqg_stats_update_io_merged(struct bfq_group *bfqg, unsigned int op) { }

void bfqg_stats_update_completion(struct bfq_group *bfqg, uint64_t start_time,

				  uint64_t io_start_time, unsigned int op) { }

void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns,

				  u64 io_start_time_ns, unsigned int op) { }

void bfqg_stats_update_dequeue(struct bfq_group *bfqg) { }

void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg) { }

void bfqg_stats_update_idle_time(struct bfq_group *bfqg) { }

block/bfq-iosched.h

+5 −5
Original line number Diff line number Diff line
@@ -732,9 +732,9 @@ struct bfqg_stats { 
	/* total time with empty current active q with other requests queued */

	struct blkg_stat		empty_time;

	/* fields after this shouldn't be cleared on stat reset */

	uint64_t			start_group_wait_time;

	uint64_t			start_idle_time;

	uint64_t			start_empty_time;

	u64				start_group_wait_time;

	u64				start_idle_time;

	u64				start_empty_time;

	uint16_t			flags;

#endif	/* CONFIG_BFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */

};
@@ -856,8 +856,8 @@ void bfqg_stats_update_io_add(struct bfq_group *bfqg, struct bfq_queue *bfqq, 
			      unsigned int op);

void bfqg_stats_update_io_remove(struct bfq_group *bfqg, unsigned int op);

void bfqg_stats_update_io_merged(struct bfq_group *bfqg, unsigned int op);

void bfqg_stats_update_completion(struct bfq_group *bfqg, uint64_t start_time,

				  uint64_t io_start_time, unsigned int op);

void bfqg_stats_update_completion(struct bfq_group *bfqg, u64 start_time_ns,

				  u64 io_start_time_ns, unsigned int op);

void bfqg_stats_update_dequeue(struct bfq_group *bfqg);

void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg);

void bfqg_stats_update_idle_time(struct bfq_group *bfqg);

block/cfq-iosched.c

+26 −23
Original line number Diff line number Diff line
@@ -210,9 +210,9 @@ struct cfqg_stats { 
	/* total time with empty current active q with other requests queued */

	struct blkg_stat		empty_time;

	/* fields after this shouldn't be cleared on stat reset */

	uint64_t			start_group_wait_time;

	uint64_t			start_idle_time;

	uint64_t			start_empty_time;

	u64				start_group_wait_time;

	u64				start_idle_time;

	u64				start_empty_time;

	uint16_t			flags;

#endif	/* CONFIG_DEBUG_BLK_CGROUP */

#endif	/* CONFIG_CFQ_GROUP_IOSCHED */
@@ -491,13 +491,13 @@ CFQG_FLAG_FNS(empty) 
/* This should be called with the queue_lock held. */

static void cfqg_stats_update_group_wait_time(struct cfqg_stats *stats)

{

	unsigned long long now;

	u64 now;



	if (!cfqg_stats_waiting(stats))

		return;



	now = sched_clock();

	if (time_after64(now, stats->start_group_wait_time))

	now = ktime_get_ns();

	if (now > stats->start_group_wait_time)

		blkg_stat_add(&stats->group_wait_time,

			      now - stats->start_group_wait_time);

	cfqg_stats_clear_waiting(stats);
@@ -513,20 +513,20 @@ static void cfqg_stats_set_start_group_wait_time(struct cfq_group *cfqg, 
		return;

	if (cfqg == curr_cfqg)

		return;

	stats->start_group_wait_time = sched_clock();

	stats->start_group_wait_time = ktime_get_ns();

	cfqg_stats_mark_waiting(stats);

}



/* This should be called with the queue_lock held. */

static void cfqg_stats_end_empty_time(struct cfqg_stats *stats)

{

	unsigned long long now;

	u64 now;



	if (!cfqg_stats_empty(stats))

		return;



	now = sched_clock();

	if (time_after64(now, stats->start_empty_time))

	now = ktime_get_ns();

	if (now > stats->start_empty_time)

		blkg_stat_add(&stats->empty_time,

			      now - stats->start_empty_time);

	cfqg_stats_clear_empty(stats);
@@ -552,7 +552,7 @@ static void cfqg_stats_set_start_empty_time(struct cfq_group *cfqg) 
	if (cfqg_stats_empty(stats))

		return;



	stats->start_empty_time = sched_clock();

	stats->start_empty_time = ktime_get_ns();

	cfqg_stats_mark_empty(stats);

}
@@ -561,9 +561,9 @@ static void cfqg_stats_update_idle_time(struct cfq_group *cfqg) 
	struct cfqg_stats *stats = &cfqg->stats;



	if (cfqg_stats_idling(stats)) {

		unsigned long long now = sched_clock();

		u64 now = ktime_get_ns();



		if (time_after64(now, stats->start_idle_time))

		if (now > stats->start_idle_time)

			blkg_stat_add(&stats->idle_time,

				      now - stats->start_idle_time);

		cfqg_stats_clear_idling(stats);
@@ -576,7 +576,7 @@ static void cfqg_stats_set_start_idle_time(struct cfq_group *cfqg) 


	BUG_ON(cfqg_stats_idling(stats));



	stats->start_idle_time = sched_clock();

	stats->start_idle_time = ktime_get_ns();

	cfqg_stats_mark_idling(stats);

}
@@ -701,17 +701,19 @@ static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg, 
}



static inline void cfqg_stats_update_completion(struct cfq_group *cfqg,

			uint64_t start_time, uint64_t io_start_time,

						u64 start_time_ns,

						u64 io_start_time_ns,

						unsigned int op)

{

	struct cfqg_stats *stats = &cfqg->stats;

	unsigned long long now = sched_clock();

	u64 now = ktime_get_ns();



	if (time_after64(now, io_start_time))

		blkg_rwstat_add(&stats->service_time, op, now - io_start_time);

	if (time_after64(io_start_time, start_time))

	if (now > io_start_time_ns)

		blkg_rwstat_add(&stats->service_time, op,

				now - io_start_time_ns);

	if (io_start_time_ns > start_time_ns)

		blkg_rwstat_add(&stats->wait_time, op,

				io_start_time - start_time);

				io_start_time_ns - start_time_ns);

}



/* @stats = 0 */
@@ -797,7 +799,8 @@ static inline void cfqg_stats_update_io_remove(struct cfq_group *cfqg, 
static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg,

			unsigned int op) { }

static inline void cfqg_stats_update_completion(struct cfq_group *cfqg,

			uint64_t start_time, uint64_t io_start_time,

						u64 start_time_ns,

						u64 io_start_time_ns,

						unsigned int op) { }



#endif	/* CONFIG_CFQ_GROUP_IOSCHED */

include/linux/blkdev.h

+6 −15
Original line number Diff line number Diff line
@@ -1799,42 +1799,33 @@ int kblockd_schedule_work_on(int cpu, struct work_struct *work); 
int kblockd_mod_delayed_work_on(int cpu, struct delayed_work *dwork, unsigned long delay);



#ifdef CONFIG_BLK_CGROUP

/*

 * This should not be using sched_clock(). A real patch is in progress

 * to fix this up, until that is in place we need to disable preemption

 * around sched_clock() in this function and set_io_start_time_ns().

 */

static inline void set_start_time_ns(struct request *req)

{

	preempt_disable();

	req->cgroup_start_time_ns = sched_clock();

	preempt_enable();

	req->cgroup_start_time_ns = ktime_get_ns();

}



static inline void set_io_start_time_ns(struct request *req)

{

	preempt_disable();

	req->cgroup_io_start_time_ns = sched_clock();

	preempt_enable();

	req->cgroup_io_start_time_ns = ktime_get_ns();

}



static inline uint64_t rq_start_time_ns(struct request *req)

static inline u64 rq_start_time_ns(struct request *req)

{

	return req->cgroup_start_time_ns;

}



static inline uint64_t rq_io_start_time_ns(struct request *req)

static inline u64 rq_io_start_time_ns(struct request *req)

{

	return req->cgroup_io_start_time_ns;

}

#else

static inline void set_start_time_ns(struct request *req) {}

static inline void set_io_start_time_ns(struct request *req) {}

static inline uint64_t rq_start_time_ns(struct request *req)

static inline u64 rq_start_time_ns(struct request *req)

{

	return 0;

}

static inline uint64_t rq_io_start_time_ns(struct request *req)

static inline u64 rq_io_start_time_ns(struct request *req)

{

	return 0;

}