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Commit 317389a7 authored by Vivek Goyal's avatar Vivek Goyal Committed by Jens Axboe
Browse files

cfq-iosched: Make IO merge related stats per cpu 



Make BLKIO_STAT_MERGED per cpu hence gettring rid of need of taking
blkg->stats_lock.

Signed-off-by: default avatarVivek Goyal <vgoyal@redhat.com>
Signed-off-by: default avatarJens Axboe <jaxboe@fusionio.com>
parent 2abae55f

block/blk-cgroup.c

+17 −5
Original line number Diff line number Diff line
@@ -441,15 +441,27 @@ void blkiocg_update_completion_stats(struct blkio_group *blkg, 
}

EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats);



/*  Merged stats are per cpu.  */

void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction,

					bool sync)

{

	struct blkio_group_stats_cpu *stats_cpu;

	unsigned long flags;



	spin_lock_irqsave(&blkg->stats_lock, flags);

	blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_MERGED], 1, direction,

			sync);

	spin_unlock_irqrestore(&blkg->stats_lock, flags);

	/*

	 * Disabling interrupts to provide mutual exclusion between two

	 * writes on same cpu. It probably is not needed for 64bit. Not

	 * optimizing that case yet.

	 */

	local_irq_save(flags);



	stats_cpu = this_cpu_ptr(blkg->stats_cpu);



	u64_stats_update_begin(&stats_cpu->syncp);

	blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_MERGED], 1,

				direction, sync);

	u64_stats_update_end(&stats_cpu->syncp);

	local_irq_restore(flags);

}

EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats);
@@ -1244,7 +1256,7 @@ static int blkiocg_file_read_map(struct cgroup *cgrp, struct cftype *cft, 
						BLKIO_STAT_WAIT_TIME, 1, 0);

		case BLKIO_PROP_io_merged:

			return blkio_read_blkg_stats(blkcg, cft, cb,

						BLKIO_STAT_MERGED, 1, 0);

						BLKIO_STAT_CPU_MERGED, 1, 1);

		case BLKIO_PROP_io_queued:

			return blkio_read_blkg_stats(blkcg, cft, cb,

						BLKIO_STAT_QUEUED, 1, 0);

block/blk-cgroup.h

+2 −2
Original line number Diff line number Diff line
@@ -39,8 +39,6 @@ enum stat_type { 
	BLKIO_STAT_SERVICE_TIME = 0,

	/* Total time spent waiting in scheduler queue in ns */

	BLKIO_STAT_WAIT_TIME,

	/* Number of IOs merged */

	BLKIO_STAT_MERGED,

	/* Number of IOs queued up */

	BLKIO_STAT_QUEUED,

	/* All the single valued stats go below this */
@@ -63,6 +61,8 @@ enum stat_type_cpu { 
	BLKIO_STAT_CPU_SERVICE_BYTES,

	/* Total IOs serviced, post merge */

	BLKIO_STAT_CPU_SERVICED,

	/* Number of IOs merged */

	BLKIO_STAT_CPU_MERGED,

	BLKIO_STAT_CPU_NR

};