diff options
| author | Vivek Goyal <vgoyal@redhat.com> | 2011-05-23 10:02:19 +0200 |
|---|---|---|
| committer | Jens Axboe <jaxboe@fusionio.com> | 2011-05-23 10:02:19 +0200 |
| commit | 317389a7739675aa990b7e0d750a7c435f1d25d7 (patch) | |
| tree | c24b7bb45d03233d76405dab4f9406c05c44eafa | |
| parent | 2abae55f5a41d29f21b5b259c33d218c950d5c90 (diff) | |
| download | lwn-317389a7739675aa990b7e0d750a7c435f1d25d7.tar.gz lwn-317389a7739675aa990b7e0d750a7c435f1d25d7.zip | |
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>
| -rw-r--r-- | block/blk-cgroup.c | 22 | ||||
| -rw-r--r-- | block/blk-cgroup.h | 4 |
2 files changed, 19 insertions, 7 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index e41cc6f2ccc1..07371cfdfae6 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -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); diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index 262226798093..a71d2904ffb9 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -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 }; |