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Diffstat (limited to 'block/blk-iolatency.c')
-rw-r--r--block/blk-iolatency.c37
1 files changed, 17 insertions, 20 deletions
diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index 571fa95aafe9..778a0057193e 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -141,7 +141,7 @@ struct iolatency_grp {
struct latency_stat __percpu *stats;
struct latency_stat cur_stat;
struct blk_iolatency *blkiolat;
- struct rq_depth rq_depth;
+ unsigned int max_depth;
struct rq_wait rq_wait;
atomic64_t window_start;
atomic_t scale_cookie;
@@ -280,7 +280,7 @@ static void iolat_cleanup_cb(struct rq_wait *rqw, void *private_data)
static bool iolat_acquire_inflight(struct rq_wait *rqw, void *private_data)
{
struct iolatency_grp *iolat = private_data;
- return rq_wait_inc_below(rqw, iolat->rq_depth.max_depth);
+ return rq_wait_inc_below(rqw, iolat->max_depth);
}
static void __blkcg_iolatency_throttle(struct rq_qos *rqos,
@@ -364,15 +364,17 @@ static void scale_cookie_change(struct blk_iolatency *blkiolat,
}
/*
- * Change the queue depth of the iolatency_grp. We add/subtract 1/16th of the
+ * Change the queue depth of the iolatency_grp. We add 1/16th of the
* queue depth at a time so we don't get wild swings and hopefully dial in to
- * fairer distribution of the overall queue depth.
+ * fairer distribution of the overall queue depth. We halve the queue depth
+ * at a time so we can scale down queue depth quickly from default unlimited
+ * to target.
*/
static void scale_change(struct iolatency_grp *iolat, bool up)
{
unsigned long qd = iolat->blkiolat->rqos.q->nr_requests;
unsigned long scale = scale_amount(qd, up);
- unsigned long old = iolat->rq_depth.max_depth;
+ unsigned long old = iolat->max_depth;
if (old > qd)
old = qd;
@@ -384,12 +386,12 @@ static void scale_change(struct iolatency_grp *iolat, bool up)
if (old < qd) {
old += scale;
old = min(old, qd);
- iolat->rq_depth.max_depth = old;
+ iolat->max_depth = old;
wake_up_all(&iolat->rq_wait.wait);
}
} else {
old >>= 1;
- iolat->rq_depth.max_depth = max(old, 1UL);
+ iolat->max_depth = max(old, 1UL);
}
}
@@ -403,9 +405,6 @@ static void check_scale_change(struct iolatency_grp *iolat)
u64 scale_lat;
int direction = 0;
- if (lat_to_blkg(iolat)->parent == NULL)
- return;
-
parent = blkg_to_lat(lat_to_blkg(iolat)->parent);
if (!parent)
return;
@@ -445,7 +444,7 @@ static void check_scale_change(struct iolatency_grp *iolat)
}
/* We're as low as we can go. */
- if (iolat->rq_depth.max_depth == 1 && direction < 0) {
+ if (iolat->max_depth == 1 && direction < 0) {
blkcg_use_delay(lat_to_blkg(iolat));
return;
}
@@ -453,7 +452,7 @@ static void check_scale_change(struct iolatency_grp *iolat)
/* We're back to the default cookie, unthrottle all the things. */
if (cur_cookie == DEFAULT_SCALE_COOKIE) {
blkcg_clear_delay(lat_to_blkg(iolat));
- iolat->rq_depth.max_depth = UINT_MAX;
+ iolat->max_depth = UINT_MAX;
wake_up_all(&iolat->rq_wait.wait);
return;
}
@@ -508,7 +507,7 @@ static void iolatency_record_time(struct iolatency_grp *iolat,
* We don't want to count issue_as_root bio's in the cgroups latency
* statistics as it could skew the numbers downwards.
*/
- if (unlikely(issue_as_root && iolat->rq_depth.max_depth != UINT_MAX)) {
+ if (unlikely(issue_as_root && iolat->max_depth != UINT_MAX)) {
u64 sub = iolat->min_lat_nsec;
if (req_time < sub)
blkcg_add_delay(lat_to_blkg(iolat), now, sub - req_time);
@@ -920,7 +919,7 @@ static void iolatency_ssd_stat(struct iolatency_grp *iolat, struct seq_file *s)
}
preempt_enable();
- if (iolat->rq_depth.max_depth == UINT_MAX)
+ if (iolat->max_depth == UINT_MAX)
seq_printf(s, " missed=%llu total=%llu depth=max",
(unsigned long long)stat.ps.missed,
(unsigned long long)stat.ps.total);
@@ -928,7 +927,7 @@ static void iolatency_ssd_stat(struct iolatency_grp *iolat, struct seq_file *s)
seq_printf(s, " missed=%llu total=%llu depth=%u",
(unsigned long long)stat.ps.missed,
(unsigned long long)stat.ps.total,
- iolat->rq_depth.max_depth);
+ iolat->max_depth);
}
static void iolatency_pd_stat(struct blkg_policy_data *pd, struct seq_file *s)
@@ -945,12 +944,12 @@ static void iolatency_pd_stat(struct blkg_policy_data *pd, struct seq_file *s)
avg_lat = div64_u64(iolat->lat_avg, NSEC_PER_USEC);
cur_win = div64_u64(iolat->cur_win_nsec, NSEC_PER_MSEC);
- if (iolat->rq_depth.max_depth == UINT_MAX)
+ if (iolat->max_depth == UINT_MAX)
seq_printf(s, " depth=max avg_lat=%llu win=%llu",
avg_lat, cur_win);
else
seq_printf(s, " depth=%u avg_lat=%llu win=%llu",
- iolat->rq_depth.max_depth, avg_lat, cur_win);
+ iolat->max_depth, avg_lat, cur_win);
}
static struct blkg_policy_data *iolatency_pd_alloc(gfp_t gfp,
@@ -994,9 +993,7 @@ static void iolatency_pd_init(struct blkg_policy_data *pd)
latency_stat_init(iolat, &iolat->cur_stat);
rq_wait_init(&iolat->rq_wait);
spin_lock_init(&iolat->child_lat.lock);
- iolat->rq_depth.queue_depth = blkg->q->nr_requests;
- iolat->rq_depth.max_depth = UINT_MAX;
- iolat->rq_depth.default_depth = iolat->rq_depth.queue_depth;
+ iolat->max_depth = UINT_MAX;
iolat->blkiolat = blkiolat;
iolat->cur_win_nsec = 100 * NSEC_PER_MSEC;
atomic64_set(&iolat->window_start, now);