diff options
| author | Christoph Hellwig <hch@lst.de> | 2019-06-06 13:26:21 +0300 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2019-06-20 19:32:34 +0300 |
| commit | 7af6fd9112ba310a889c60d0606b4b74049cfe14 (patch) | |
| tree | 82110ea85453bdc5860bdba93d791f8f367070e7 /include/linux/blk-cgroup.h | |
| parent | 5d0b6e48cbef3219c0ed75e0e746c4ed259303c2 (diff) | |
| download | linux-7af6fd9112ba310a889c60d0606b4b74049cfe14.tar.xz | |
blk-cgroup: introduce a new struct blkg_rwstat_sample
When sampling the blkcg counts we don't need atomics or per-cpu
variables. Introduce a new structure just containing plain u64
counters.
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'include/linux/blk-cgroup.h')
| -rw-r--r-- | include/linux/blk-cgroup.h | 22 |
1 files changed, 12 insertions, 10 deletions
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index 3ee858111274..e4a81767e111 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -63,8 +63,7 @@ struct blkcg { /* * blkg_[rw]stat->aux_cnt is excluded for local stats but included for - * recursive. Used to carry stats of dead children, and, for blkg_rwstat, - * to carry result values from read and sum operations. + * recursive. Used to carry stats of dead children. */ struct blkg_stat { struct percpu_counter cpu_cnt; @@ -76,6 +75,10 @@ struct blkg_rwstat { atomic64_t aux_cnt[BLKG_RWSTAT_NR]; }; +struct blkg_rwstat_sample { + u64 cnt[BLKG_RWSTAT_NR]; +}; + /* * A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a * request_queue (q). This is used by blkcg policies which need to track @@ -213,7 +216,7 @@ void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg, bool show_total); u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v); u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd, - const struct blkg_rwstat *rwstat); + const struct blkg_rwstat_sample *rwstat); u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off); u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd, int off); @@ -225,7 +228,7 @@ int blkg_print_stat_ios_recursive(struct seq_file *sf, void *v); u64 blkg_stat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol, int off); void blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol, - int off, struct blkg_rwstat *sum); + int off, struct blkg_rwstat_sample *sum); struct blkg_conf_ctx { struct gendisk *disk; @@ -701,13 +704,13 @@ static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat, * Read the current snapshot of @rwstat and return it in the aux counts. */ static inline void blkg_rwstat_read(struct blkg_rwstat *rwstat, - struct blkg_rwstat *result) + struct blkg_rwstat_sample *result) { int i; for (i = 0; i < BLKG_RWSTAT_NR; i++) - atomic64_set(&result->aux_cnt[i], - percpu_counter_sum_positive(&rwstat->cpu_cnt[i])); + result->cnt[i] = + percpu_counter_sum_positive(&rwstat->cpu_cnt[i]); } /** @@ -720,11 +723,10 @@ static inline void blkg_rwstat_read(struct blkg_rwstat *rwstat, */ static inline uint64_t blkg_rwstat_total(struct blkg_rwstat *rwstat) { - struct blkg_rwstat tmp = { }; + struct blkg_rwstat_sample tmp = { }; blkg_rwstat_read(rwstat, &tmp); - return atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_READ]) + - atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_WRITE]); + return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE]; } /** |