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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: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This commit is contained in:
Vivek Goyal 2011-05-23 10:02:19 +02:00 committed by Jens Axboe
parent 2abae55f5a
commit 317389a773
2 changed files with 19 additions and 7 deletions
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22
block/blk-cgroup.c
View File

@ -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);

4
block/blk-cgroup.h
View File

@ -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
};