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Commit 702747ca authored by Tejun Heo's avatar Tejun Heo Committed by Jens Axboe
Browse files

blkcg: remove cfqg_stats->sectors 



cfq_stats->sectors is a blkg_stat which keeps track of the total
number of sectors serviced; however, this can be trivially calculated
from blkcg_gq->stat_bytes.  The only thing necessary is adding up
READs and WRITEs and then dividing by sector size.

Remove cfqg_stats->sectors and make cfq print "sectors" and
"sectors_recursive" from stat_bytes.

While this is a bit more code, it removes duplicate stat allocations
and updates and ensures that the reported stats stay in tune with each
other.

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: default avatarJens Axboe <axboe@fb.com>
parent 77ea7338

block/cfq-iosched.c

+36 −19
Original line number Diff line number Diff line
@@ -185,8 +185,6 @@ struct cfqg_stats { 
	struct blkg_rwstat		wait_time;

	/* number of IOs queued up */

	struct blkg_rwstat		queued;

	/* total sectors transferred */

	struct blkg_stat		sectors;

	/* total disk time and nr sectors dispatched by this group */

	struct blkg_stat		time;

#ifdef CONFIG_DEBUG_BLK_CGROUP
@@ -688,12 +686,6 @@ static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg, int rw) 
	blkg_rwstat_add(&cfqg->stats.merged, rw, 1);

}



static inline void cfqg_stats_update_dispatch(struct cfq_group *cfqg,

					      uint64_t bytes, int rw)

{

	blkg_stat_add(&cfqg->stats.sectors, bytes >> 9);

}



static inline void cfqg_stats_update_completion(struct cfq_group *cfqg,

			uint64_t start_time, uint64_t io_start_time, int rw)

{
@@ -782,8 +774,6 @@ static inline void cfqg_stats_update_timeslice_used(struct cfq_group *cfqg, 
			unsigned long time, unsigned long unaccounted_time) { }

static inline void cfqg_stats_update_io_remove(struct cfq_group *cfqg, int rw) { }

static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg, int rw) { }

static inline void cfqg_stats_update_dispatch(struct cfq_group *cfqg,

					      uint64_t bytes, int rw) { }

static inline void cfqg_stats_update_completion(struct cfq_group *cfqg,

			uint64_t start_time, uint64_t io_start_time, int rw) { }
@@ -1538,8 +1528,6 @@ static void cfqg_stats_exit(struct cfqg_stats *stats) 
	blkg_rwstat_exit(&stats->service_time);

	blkg_rwstat_exit(&stats->wait_time);

	blkg_rwstat_exit(&stats->queued);



	blkg_stat_exit(&stats->sectors);

	blkg_stat_exit(&stats->time);

#ifdef CONFIG_DEBUG_BLK_CGROUP

	blkg_stat_exit(&stats->unaccounted_time);
@@ -1558,8 +1546,6 @@ static int cfqg_stats_init(struct cfqg_stats *stats, gfp_t gfp) 
	    blkg_rwstat_init(&stats->service_time, gfp) ||

	    blkg_rwstat_init(&stats->wait_time, gfp) ||

	    blkg_rwstat_init(&stats->queued, gfp) ||



	    blkg_stat_init(&stats->sectors, gfp) ||

	    blkg_stat_init(&stats->time, gfp))

		goto err;
@@ -1901,6 +1887,40 @@ static int cfqg_print_rwstat_recursive(struct seq_file *sf, void *v) 
	return 0;

}



static u64 cfqg_prfill_sectors(struct seq_file *sf, struct blkg_policy_data *pd,

			       int off)

{

	u64 sum = blkg_rwstat_total(&pd->blkg->stat_bytes);



	return __blkg_prfill_u64(sf, pd, sum >> 9);

}



static int cfqg_print_stat_sectors(struct seq_file *sf, void *v)

{

	blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),

			  cfqg_prfill_sectors, &blkcg_policy_cfq, 0, false);

	return 0;

}



static u64 cfqg_prfill_sectors_recursive(struct seq_file *sf,

					 struct blkg_policy_data *pd, int off)

{

	struct blkg_rwstat tmp = blkg_rwstat_recursive_sum(pd->blkg, NULL,

					offsetof(struct blkcg_gq, stat_bytes));

	u64 sum = atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_READ]) +

		atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_WRITE]);



	return __blkg_prfill_u64(sf, pd, sum >> 9);

}



static int cfqg_print_stat_sectors_recursive(struct seq_file *sf, void *v)

{

	blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),

			  cfqg_prfill_sectors_recursive, &blkcg_policy_cfq, 0,

			  false);

	return 0;

}



#ifdef CONFIG_DEBUG_BLK_CGROUP

static u64 cfqg_prfill_avg_queue_size(struct seq_file *sf,

				      struct blkg_policy_data *pd, int off)
@@ -1975,8 +1995,7 @@ static struct cftype cfq_blkcg_files[] = { 
	},

	{

		.name = "sectors",

		.private = offsetof(struct cfq_group, stats.sectors),

		.seq_show = cfqg_print_stat,

		.seq_show = cfqg_print_stat_sectors,

	},

	{

		.name = "io_service_bytes",
@@ -2017,8 +2036,7 @@ static struct cftype cfq_blkcg_files[] = { 
	},

	{

		.name = "sectors_recursive",

		.private = offsetof(struct cfq_group, stats.sectors),

		.seq_show = cfqg_print_stat_recursive,

		.seq_show = cfqg_print_stat_sectors_recursive,

	},

	{

		.name = "io_service_bytes_recursive",
@@ -2888,7 +2906,6 @@ static void cfq_dispatch_insert(struct request_queue *q, struct request *rq) 


	cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]++;

	cfqq->nr_sectors += blk_rq_sectors(rq);

	cfqg_stats_update_dispatch(cfqq->cfqg, blk_rq_bytes(rq), rq->cmd_flags);

}



/*