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authorTejun Heo <tj@kernel.org>2015-08-18 14:55:22 -0700
committerJens Axboe <axboe@fb.com>2015-08-18 15:49:17 -0700
commit24bdb8ef068ebdc2a57ce715f0ab22d5da32832a (patch)
tree466def9b935d1a40ce63cd07607e4a7be551f6bd /block/blk-cgroup.c
parente6269c44546755094979ab53609e6e203a68c8ff (diff)
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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.c10
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();