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authorChristoph Hellwig <hch@lst.de>2019-06-06 12:26:21 +0200
committerJens Axboe <axboe@kernel.dk>2019-06-20 10:32:34 -0600
commit7af6fd9112ba310a889c60d0606b4b74049cfe14 (patch)
tree82110ea85453bdc5860bdba93d791f8f367070e7 /block
parent5d0b6e48cbef3219c0ed75e0e746c4ed259303c2 (diff)
downloadlinux-7af6fd9112ba310a889c60d0606b4b74049cfe14.tar.bz2
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 'block')
-rw-r--r--block/bfq-cgroup.c10
-rw-r--r--block/blk-cgroup.c39
2 files changed, 23 insertions, 26 deletions
diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
index 66abc82179f3..624374a99c6e 100644
--- a/block/bfq-cgroup.c
+++ b/block/bfq-cgroup.c
@@ -935,7 +935,7 @@ static u64 bfqg_prfill_stat_recursive(struct seq_file *sf,
static u64 bfqg_prfill_rwstat_recursive(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
- struct blkg_rwstat sum;
+ struct blkg_rwstat_sample sum;
blkg_rwstat_recursive_sum(pd_to_blkg(pd), &blkcg_policy_bfq, off, &sum);
return __blkg_prfill_rwstat(sf, pd, &sum);
@@ -975,15 +975,13 @@ static int bfqg_print_stat_sectors(struct seq_file *sf, void *v)
static u64 bfqg_prfill_sectors_recursive(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
- struct blkg_rwstat tmp;
- u64 sum;
+ struct blkg_rwstat_sample tmp;
blkg_rwstat_recursive_sum(pd->blkg, NULL,
offsetof(struct blkcg_gq, stat_bytes), &tmp);
- sum = atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_READ]) +
- atomic64_read(&tmp.aux_cnt[BLKG_RWSTAT_WRITE]);
- return __blkg_prfill_u64(sf, pd, sum >> 9);
+ return __blkg_prfill_u64(sf, pd,
+ (tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE]) >> 9);
}
static int bfqg_print_stat_sectors_recursive(struct seq_file *sf, void *v)
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index db039a869d95..664c09866839 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -544,7 +544,7 @@ EXPORT_SYMBOL_GPL(__blkg_prfill_u64);
* Print @rwstat to @sf for the device assocaited with @pd.
*/
u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
- const struct blkg_rwstat *rwstat)
+ const struct blkg_rwstat_sample *rwstat)
{
static const char *rwstr[] = {
[BLKG_RWSTAT_READ] = "Read",
@@ -562,12 +562,12 @@ 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)atomic64_read(&rwstat->aux_cnt[i]));
+ rwstat->cnt[i]);
- v = atomic64_read(&rwstat->aux_cnt[BLKG_RWSTAT_READ]) +
- atomic64_read(&rwstat->aux_cnt[BLKG_RWSTAT_WRITE]) +
- atomic64_read(&rwstat->aux_cnt[BLKG_RWSTAT_DISCARD]);
- seq_printf(sf, "%s Total %llu\n", dname, (unsigned long long)v);
+ v = rwstat->cnt[BLKG_RWSTAT_READ] +
+ rwstat->cnt[BLKG_RWSTAT_WRITE] +
+ rwstat->cnt[BLKG_RWSTAT_DISCARD];
+ seq_printf(sf, "%s Total %llu\n", dname, v);
return v;
}
EXPORT_SYMBOL_GPL(__blkg_prfill_rwstat);
@@ -597,7 +597,7 @@ EXPORT_SYMBOL_GPL(blkg_prfill_stat);
u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
int off)
{
- struct blkg_rwstat rwstat = { };
+ struct blkg_rwstat_sample rwstat = { };
blkg_rwstat_read((void *)pd + off, &rwstat);
return __blkg_prfill_rwstat(sf, pd, &rwstat);
@@ -607,7 +607,7 @@ EXPORT_SYMBOL_GPL(blkg_prfill_rwstat);
static u64 blkg_prfill_rwstat_field(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
- struct blkg_rwstat rwstat = { };
+ struct blkg_rwstat_sample rwstat = { };
blkg_rwstat_read((void *)pd->blkg + off, &rwstat);
return __blkg_prfill_rwstat(sf, pd, &rwstat);
@@ -651,7 +651,7 @@ static u64 blkg_prfill_rwstat_field_recursive(struct seq_file *sf,
struct blkg_policy_data *pd,
int off)
{
- struct blkg_rwstat rwstat;
+ struct blkg_rwstat_sample rwstat;
blkg_rwstat_recursive_sum(pd->blkg, NULL, off, &rwstat);
return __blkg_prfill_rwstat(sf, pd, &rwstat);
@@ -734,7 +734,7 @@ EXPORT_SYMBOL_GPL(blkg_stat_recursive_sum);
* @blkg: blkg of interest
* @pol: blkcg_policy which contains the blkg_rwstat
* @off: offset to the blkg_rwstat in blkg_policy_data or @blkg
- * @sum: blkg_rwstat structure containing the results
+ * @sum: blkg_rwstat_sample structure containing the results
*
* Collect the blkg_rwstat specified by @blkg, @pol and @off and all its
* online descendants and their aux counts. The caller must be holding the
@@ -744,7 +744,7 @@ EXPORT_SYMBOL_GPL(blkg_stat_recursive_sum);
* is at @off bytes into @blkg's blkg_policy_data of the policy.
*/
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 blkcg_gq *pos_blkg;
struct cgroup_subsys_state *pos_css;
@@ -765,8 +765,7 @@ void blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol,
rwstat = (void *)pos_blkg + off;
for (i = 0; i < BLKG_RWSTAT_NR; i++)
- atomic64_set(&sum->aux_cnt[i],
- blkg_rwstat_read_counter(rwstat, i));
+ sum->cnt[i] = blkg_rwstat_read_counter(rwstat, i);
}
rcu_read_unlock();
}
@@ -934,7 +933,7 @@ static int blkcg_print_stat(struct seq_file *sf, void *v)
hlist_for_each_entry_rcu(blkg, &blkcg->blkg_list, blkcg_node) {
const char *dname;
char *buf;
- struct blkg_rwstat rwstat;
+ struct blkg_rwstat_sample rwstat;
u64 rbytes, wbytes, rios, wios, dbytes, dios;
size_t size = seq_get_buf(sf, &buf), off = 0;
int i;
@@ -956,15 +955,15 @@ static int blkcg_print_stat(struct seq_file *sf, void *v)
blkg_rwstat_recursive_sum(blkg, NULL,
offsetof(struct blkcg_gq, stat_bytes), &rwstat);
- rbytes = atomic64_read(&rwstat.aux_cnt[BLKG_RWSTAT_READ]);
- wbytes = atomic64_read(&rwstat.aux_cnt[BLKG_RWSTAT_WRITE]);
- dbytes = atomic64_read(&rwstat.aux_cnt[BLKG_RWSTAT_DISCARD]);
+ rbytes = rwstat.cnt[BLKG_RWSTAT_READ];
+ wbytes = rwstat.cnt[BLKG_RWSTAT_WRITE];
+ dbytes = rwstat.cnt[BLKG_RWSTAT_DISCARD];
blkg_rwstat_recursive_sum(blkg, NULL,
offsetof(struct blkcg_gq, stat_ios), &rwstat);
- rios = atomic64_read(&rwstat.aux_cnt[BLKG_RWSTAT_READ]);
- wios = atomic64_read(&rwstat.aux_cnt[BLKG_RWSTAT_WRITE]);
- dios = atomic64_read(&rwstat.aux_cnt[BLKG_RWSTAT_DISCARD]);
+ rios = rwstat.cnt[BLKG_RWSTAT_READ];
+ wios = rwstat.cnt[BLKG_RWSTAT_WRITE];
+ dios = rwstat.cnt[BLKG_RWSTAT_DISCARD];
spin_unlock_irq(&blkg->q->queue_lock);