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-rw-r--r--block/blk-cgroup.c159
1 files changed, 156 insertions, 3 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 1e0c4970b35d..1ecff7a39f2c 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -105,6 +105,76 @@ static void blkio_check_and_dec_stat(uint64_t *stat, bool direction, bool sync)
}
#ifdef CONFIG_DEBUG_BLK_CGROUP
+/* This should be called with the blkg->stats_lock held. */
+static void blkio_set_start_group_wait_time(struct blkio_group *blkg,
+ struct blkio_group *curr_blkg)
+{
+ if (blkio_blkg_waiting(&blkg->stats))
+ return;
+ if (blkg == curr_blkg)
+ return;
+ blkg->stats.start_group_wait_time = sched_clock();
+ blkio_mark_blkg_waiting(&blkg->stats);
+}
+
+/* This should be called with the blkg->stats_lock held. */
+static void blkio_update_group_wait_time(struct blkio_group_stats *stats)
+{
+ unsigned long long now;
+
+ if (!blkio_blkg_waiting(stats))
+ return;
+
+ now = sched_clock();
+ if (time_after64(now, stats->start_group_wait_time))
+ stats->group_wait_time += now - stats->start_group_wait_time;
+ blkio_clear_blkg_waiting(stats);
+}
+
+/* This should be called with the blkg->stats_lock held. */
+static void blkio_end_empty_time(struct blkio_group_stats *stats)
+{
+ unsigned long long now;
+
+ if (!blkio_blkg_empty(stats))
+ return;
+
+ now = sched_clock();
+ if (time_after64(now, stats->start_empty_time))
+ stats->empty_time += now - stats->start_empty_time;
+ blkio_clear_blkg_empty(stats);
+}
+
+void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&blkg->stats_lock, flags);
+ BUG_ON(blkio_blkg_idling(&blkg->stats));
+ blkg->stats.start_idle_time = sched_clock();
+ blkio_mark_blkg_idling(&blkg->stats);
+ spin_unlock_irqrestore(&blkg->stats_lock, flags);
+}
+EXPORT_SYMBOL_GPL(blkiocg_update_set_idle_time_stats);
+
+void blkiocg_update_idle_time_stats(struct blkio_group *blkg)
+{
+ unsigned long flags;
+ unsigned long long now;
+ struct blkio_group_stats *stats;
+
+ spin_lock_irqsave(&blkg->stats_lock, flags);
+ stats = &blkg->stats;
+ if (blkio_blkg_idling(stats)) {
+ now = sched_clock();
+ if (time_after64(now, stats->start_idle_time))
+ stats->idle_time += now - stats->start_idle_time;
+ blkio_clear_blkg_idling(stats);
+ }
+ spin_unlock_irqrestore(&blkg->stats_lock, flags);
+}
+EXPORT_SYMBOL_GPL(blkiocg_update_idle_time_stats);
+
void blkiocg_update_set_active_queue_stats(struct blkio_group *blkg)
{
unsigned long flags;
@@ -116,9 +186,14 @@ void blkiocg_update_set_active_queue_stats(struct blkio_group *blkg)
stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] +
stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE];
stats->avg_queue_size_samples++;
+ blkio_update_group_wait_time(stats);
spin_unlock_irqrestore(&blkg->stats_lock, flags);
}
EXPORT_SYMBOL_GPL(blkiocg_update_set_active_queue_stats);
+#else
+static inline void blkio_set_start_group_wait_time(struct blkio_group *blkg,
+ struct blkio_group *curr_blkg) {}
+static inline void blkio_end_empty_time(struct blkio_group_stats *stats) {}
#endif
void blkiocg_update_request_add_stats(struct blkio_group *blkg,
@@ -130,6 +205,8 @@ void blkiocg_update_request_add_stats(struct blkio_group *blkg,
spin_lock_irqsave(&blkg->stats_lock, flags);
blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED], 1, direction,
sync);
+ blkio_end_empty_time(&blkg->stats);
+ blkio_set_start_group_wait_time(blkg, curr_blkg);
spin_unlock_irqrestore(&blkg->stats_lock, flags);
}
EXPORT_SYMBOL_GPL(blkiocg_update_request_add_stats);
@@ -156,6 +233,33 @@ void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time)
}
EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used);
+void blkiocg_set_start_empty_time(struct blkio_group *blkg, bool ignore)
+{
+ unsigned long flags;
+ struct blkio_group_stats *stats;
+
+ spin_lock_irqsave(&blkg->stats_lock, flags);
+ stats = &blkg->stats;
+
+ if (stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] ||
+ stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]) {
+ spin_unlock_irqrestore(&blkg->stats_lock, flags);
+ return;
+ }
+
+ /*
+ * If ignore is set, we do not panic on the empty flag being set
+ * already. This is to avoid cases where there are superfluous timeslice
+ * complete events (for eg., forced_dispatch in CFQ) when no IOs are
+ * served which could result in triggering the empty check incorrectly.
+ */
+ BUG_ON(!ignore && blkio_blkg_empty(stats));
+ stats->start_empty_time = sched_clock();
+ blkio_mark_blkg_empty(stats);
+ spin_unlock_irqrestore(&blkg->stats_lock, flags);
+}
+EXPORT_SYMBOL_GPL(blkiocg_set_start_empty_time);
+
void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
uint64_t bytes, bool direction, bool sync)
{
@@ -317,19 +421,44 @@ blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val)
{
struct blkio_cgroup *blkcg;
struct blkio_group *blkg;
+ struct blkio_group_stats *stats;
struct hlist_node *n;
uint64_t queued[BLKIO_STAT_TOTAL];
int i;
+#ifdef CONFIG_DEBUG_BLK_CGROUP
+ bool idling, waiting, empty;
+ unsigned long long now = sched_clock();
+#endif
blkcg = cgroup_to_blkio_cgroup(cgroup);
spin_lock_irq(&blkcg->lock);
hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
spin_lock(&blkg->stats_lock);
+ stats = &blkg->stats;
+#ifdef CONFIG_DEBUG_BLK_CGROUP
+ idling = blkio_blkg_idling(stats);
+ waiting = blkio_blkg_waiting(stats);
+ empty = blkio_blkg_empty(stats);
+#endif
for (i = 0; i < BLKIO_STAT_TOTAL; i++)
- queued[i] = blkg->stats.stat_arr[BLKIO_STAT_QUEUED][i];
- memset(&blkg->stats, 0, sizeof(struct blkio_group_stats));
+ queued[i] = stats->stat_arr[BLKIO_STAT_QUEUED][i];
+ memset(stats, 0, sizeof(struct blkio_group_stats));
for (i = 0; i < BLKIO_STAT_TOTAL; i++)
- blkg->stats.stat_arr[BLKIO_STAT_QUEUED][i] = queued[i];
+ stats->stat_arr[BLKIO_STAT_QUEUED][i] = queued[i];
+#ifdef CONFIG_DEBUG_BLK_CGROUP
+ if (idling) {
+ blkio_mark_blkg_idling(stats);
+ stats->start_idle_time = now;
+ }
+ if (waiting) {
+ blkio_mark_blkg_waiting(stats);
+ stats->start_group_wait_time = now;
+ }
+ if (empty) {
+ blkio_mark_blkg_empty(stats);
+ stats->start_empty_time = now;
+ }
+#endif
spin_unlock(&blkg->stats_lock);
}
spin_unlock_irq(&blkcg->lock);
@@ -401,6 +530,15 @@ static uint64_t blkio_get_stat(struct blkio_group *blkg,
sum = 0;
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, sum, cb, dev);
}
+ if (type == BLKIO_STAT_GROUP_WAIT_TIME)
+ return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
+ blkg->stats.group_wait_time, cb, dev);
+ if (type == BLKIO_STAT_IDLE_TIME)
+ return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
+ blkg->stats.idle_time, cb, dev);
+ if (type == BLKIO_STAT_EMPTY_TIME)
+ return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
+ blkg->stats.empty_time, cb, dev);
if (type == BLKIO_STAT_DEQUEUE)
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
blkg->stats.dequeue, cb, dev);
@@ -458,6 +596,9 @@ SHOW_FUNCTION_PER_GROUP(io_queued, BLKIO_STAT_QUEUED, 1);
#ifdef CONFIG_DEBUG_BLK_CGROUP
SHOW_FUNCTION_PER_GROUP(dequeue, BLKIO_STAT_DEQUEUE, 0);
SHOW_FUNCTION_PER_GROUP(avg_queue_size, BLKIO_STAT_AVG_QUEUE_SIZE, 0);
+SHOW_FUNCTION_PER_GROUP(group_wait_time, BLKIO_STAT_GROUP_WAIT_TIME, 0);
+SHOW_FUNCTION_PER_GROUP(idle_time, BLKIO_STAT_IDLE_TIME, 0);
+SHOW_FUNCTION_PER_GROUP(empty_time, BLKIO_STAT_EMPTY_TIME, 0);
#endif
#undef SHOW_FUNCTION_PER_GROUP
@@ -518,6 +659,18 @@ struct cftype blkio_files[] = {
.read_map = blkiocg_avg_queue_size_read,
},
{
+ .name = "group_wait_time",
+ .read_map = blkiocg_group_wait_time_read,
+ },
+ {
+ .name = "idle_time",
+ .read_map = blkiocg_idle_time_read,
+ },
+ {
+ .name = "empty_time",
+ .read_map = blkiocg_empty_time_read,
+ },
+ {
.name = "dequeue",
.read_map = blkiocg_dequeue_read,
},