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-rw-r--r--block/blk-iolatency.c56
1 files changed, 48 insertions, 8 deletions
diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index fc714ef402a6..2620baa1f699 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -72,6 +72,7 @@
#include <linux/sched/loadavg.h>
#include <linux/sched/signal.h>
#include <trace/events/block.h>
+#include <linux/blk-mq.h>
#include "blk-rq-qos.h"
#include "blk-stat.h"
@@ -591,6 +592,7 @@ static void blkcg_iolatency_done_bio(struct rq_qos *rqos, struct bio *bio)
u64 now = ktime_to_ns(ktime_get());
bool issue_as_root = bio_issue_as_root_blkg(bio);
bool enabled = false;
+ int inflight = 0;
blkg = bio->bi_blkg;
if (!blkg || !bio_flagged(bio, BIO_TRACKED))
@@ -601,6 +603,9 @@ static void blkcg_iolatency_done_bio(struct rq_qos *rqos, struct bio *bio)
return;
enabled = blk_iolatency_enabled(iolat->blkiolat);
+ if (!enabled)
+ return;
+
while (blkg && blkg->parent) {
iolat = blkg_to_lat(blkg);
if (!iolat) {
@@ -609,8 +614,9 @@ static void blkcg_iolatency_done_bio(struct rq_qos *rqos, struct bio *bio)
}
rqw = &iolat->rq_wait;
- atomic_dec(&rqw->inflight);
- if (!enabled || iolat->min_lat_nsec == 0)
+ inflight = atomic_dec_return(&rqw->inflight);
+ WARN_ON_ONCE(inflight < 0);
+ if (iolat->min_lat_nsec == 0)
goto next;
iolatency_record_time(iolat, &bio->bi_issue, now,
issue_as_root);
@@ -754,10 +760,13 @@ int blk_iolatency_init(struct request_queue *q)
return 0;
}
-static void iolatency_set_min_lat_nsec(struct blkcg_gq *blkg, u64 val)
+/*
+ * return 1 for enabling iolatency, return -1 for disabling iolatency, otherwise
+ * return 0.
+ */
+static int iolatency_set_min_lat_nsec(struct blkcg_gq *blkg, u64 val)
{
struct iolatency_grp *iolat = blkg_to_lat(blkg);
- struct blk_iolatency *blkiolat = iolat->blkiolat;
u64 oldval = iolat->min_lat_nsec;
iolat->min_lat_nsec = val;
@@ -766,9 +775,10 @@ static void iolatency_set_min_lat_nsec(struct blkcg_gq *blkg, u64 val)
BLKIOLATENCY_MAX_WIN_SIZE);
if (!oldval && val)
- atomic_inc(&blkiolat->enabled);
+ return 1;
if (oldval && !val)
- atomic_dec(&blkiolat->enabled);
+ return -1;
+ return 0;
}
static void iolatency_clear_scaling(struct blkcg_gq *blkg)
@@ -800,6 +810,7 @@ static ssize_t iolatency_set_limit(struct kernfs_open_file *of, char *buf,
u64 lat_val = 0;
u64 oldval;
int ret;
+ int enable = 0;
ret = blkg_conf_prep(blkcg, &blkcg_policy_iolatency, buf, &ctx);
if (ret)
@@ -834,7 +845,12 @@ static ssize_t iolatency_set_limit(struct kernfs_open_file *of, char *buf,
blkg = ctx.blkg;
oldval = iolat->min_lat_nsec;
- iolatency_set_min_lat_nsec(blkg, lat_val);
+ enable = iolatency_set_min_lat_nsec(blkg, lat_val);
+ if (enable) {
+ WARN_ON_ONCE(!blk_get_queue(blkg->q));
+ blkg_get(blkg);
+ }
+
if (oldval != iolat->min_lat_nsec) {
iolatency_clear_scaling(blkg);
}
@@ -842,6 +858,24 @@ static ssize_t iolatency_set_limit(struct kernfs_open_file *of, char *buf,
ret = 0;
out:
blkg_conf_finish(&ctx);
+ if (ret == 0 && enable) {
+ struct iolatency_grp *tmp = blkg_to_lat(blkg);
+ struct blk_iolatency *blkiolat = tmp->blkiolat;
+
+ blk_mq_freeze_queue(blkg->q);
+
+ if (enable == 1)
+ atomic_inc(&blkiolat->enabled);
+ else if (enable == -1)
+ atomic_dec(&blkiolat->enabled);
+ else
+ WARN_ON_ONCE(1);
+
+ blk_mq_unfreeze_queue(blkg->q);
+
+ blkg_put(blkg);
+ blk_put_queue(blkg->q);
+ }
return ret ?: nbytes;
}
@@ -977,8 +1011,14 @@ static void iolatency_pd_offline(struct blkg_policy_data *pd)
{
struct iolatency_grp *iolat = pd_to_lat(pd);
struct blkcg_gq *blkg = lat_to_blkg(iolat);
+ struct blk_iolatency *blkiolat = iolat->blkiolat;
+ int ret;
- iolatency_set_min_lat_nsec(blkg, 0);
+ ret = iolatency_set_min_lat_nsec(blkg, 0);
+ if (ret == 1)
+ atomic_inc(&blkiolat->enabled);
+ if (ret == -1)
+ atomic_dec(&blkiolat->enabled);
iolatency_clear_scaling(blkg);
}