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blk-cgroup: factor out a helper to read rwstat counter

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Trying to break up the crazy statements to something readable.
Also switch to an unsigned counter as it can't ever turn negative.

Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Christoph Hellwig 2019-06-06 12:26:19 +02:00 committed by Jens Axboe
parent 1aa0a133fb
commit 239eeb0857
2 changed files with 9 additions and 3 deletions
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5
block/blk-cgroup.c
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@ -745,7 +745,7 @@ struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkcg_gq *blkg,
struct blkcg_gq *pos_blkg;
struct cgroup_subsys_state *pos_css;
struct blkg_rwstat sum = { };
int i;
unsigned int i;
lockdep_assert_held(&blkg->q->queue_lock);
@ -762,8 +762,7 @@ struct blkg_rwstat blkg_rwstat_recursive_sum(struct blkcg_gq *blkg,
rwstat = (void *)pos_blkg + off;
for (i = 0; i < BLKG_RWSTAT_NR; i++)
atomic64_add(atomic64_read(&rwstat->aux_cnt[i]) +
percpu_counter_sum_positive(&rwstat->cpu_cnt[i]),
atomic64_add(blkg_rwstat_read_counter(rwstat, i),
&sum.aux_cnt[i]);
}
rcu_read_unlock();

7
include/linux/blk-cgroup.h
View File

@ -198,6 +198,13 @@ int blkcg_activate_policy(struct request_queue *q,
void blkcg_deactivate_policy(struct request_queue *q,
const struct blkcg_policy *pol);
static inline u64 blkg_rwstat_read_counter(struct blkg_rwstat *rwstat,
unsigned int idx)
{
return atomic64_read(&rwstat->aux_cnt[idx]) +
percpu_counter_sum_positive(&rwstat->cpu_cnt[idx]);
}
const char *blkg_dev_name(struct blkcg_gq *blkg);
void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
u64 (*prfill)(struct seq_file *,