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| author | Tejun Heo <tj@kernel.org> | 2015-08-18 14:55:22 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2015-08-18 15:49:17 -0700 |
| commit | 24bdb8ef068ebdc2a57ce715f0ab22d5da32832a (patch) | |
| tree | 466def9b935d1a40ce63cd07607e4a7be551f6bd /block/blk-cgroup.c | |
| parent | e6269c44546755094979ab53609e6e203a68c8ff (diff) | |
| download | lwn-24bdb8ef068ebdc2a57ce715f0ab22d5da32832a.tar.gz lwn-24bdb8ef068ebdc2a57ce715f0ab22d5da32832a.zip | |
blkcg: make blkcg_[rw]stat per-cpu
blkcg_[rw]stat are used as stat counters for blkcg policies. It isn't
per-cpu by itself and blk-throttle makes it per-cpu by wrapping around
it. This patch makes blkcg_[rw]stat per-cpu and drop the ad-hoc
per-cpu wrapping in blk-throttle.
* blkg_[rw]stat->cnt is replaced with cpu_cnt which is struct
percpu_counter. This makes syncp unnecessary as remote accesses are
handled by percpu_counter itself.
* blkg_[rw]stat_init() can now fail due to percpu allocation failure
and thus are updated to return int.
* percpu_counters need explicit freeing. blkg_[rw]stat_exit() added.
* As blkg_rwstat->cpu_cnt[] can't be read directly anymore, reading
and summing results are stored in ->aux_cnt[] instead.
* Custom per-cpu stat implementation in blk-throttle is removed.
This makes all blkcg stat counters per-cpu without complicating policy
implmentations.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block/blk-cgroup.c')
| -rw-r--r-- | block/blk-cgroup.c | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index ff79b52d1a0e..02a2d029b5a5 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -539,9 +539,10 @@ u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd, for (i = 0; i < BLKG_RWSTAT_NR; i++) seq_printf(sf, "%s %s %llu\n", dname, rwstr[i], - (unsigned long long)rwstat->cnt[i]); + (unsigned long long)atomic64_read(&rwstat->aux_cnt[i])); - v = rwstat->cnt[BLKG_RWSTAT_READ] + rwstat->cnt[BLKG_RWSTAT_WRITE]; + v = atomic64_read(&rwstat->aux_cnt[BLKG_RWSTAT_READ]) + + atomic64_read(&rwstat->aux_cnt[BLKG_RWSTAT_WRITE]); seq_printf(sf, "%s Total %llu\n", dname, (unsigned long long)v); return v; } @@ -643,8 +644,9 @@ struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkg_policy_data *pd, tmp = blkg_rwstat_read(rwstat); for (i = 0; i < BLKG_RWSTAT_NR; i++) - sum.cnt[i] += tmp.cnt[i] + - atomic64_read(&rwstat->aux_cnt[i]); + atomic64_add(atomic64_read(&tmp.aux_cnt[i]) + + atomic64_read(&rwstat->aux_cnt[i]), + &sum.aux_cnt[i]); } rcu_read_unlock(); |