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-rw-r--r--block/blk-throttle.c31
1 files changed, 18 insertions, 13 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index d5b7a2354ad7..1623507ed56e 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -1816,24 +1816,29 @@ static bool throtl_tg_is_idle(struct throtl_grp *tg)
return ret;
}
-static bool throtl_tg_can_upgrade(struct throtl_grp *tg)
+static bool throtl_low_limit_reached(struct throtl_grp *tg, int rw)
{
struct throtl_service_queue *sq = &tg->service_queue;
- bool read_limit, write_limit;
+ bool limit = tg->bps[rw][LIMIT_LOW] || tg->iops[rw][LIMIT_LOW];
/*
- * if cgroup reaches low limit (if low limit is 0, the cgroup always
- * reaches), it's ok to upgrade to next limit
+ * if low limit is zero, low limit is always reached.
+ * if low limit is non-zero, we can check if there is any request
+ * is queued to determine if low limit is reached as we throttle
+ * request according to limit.
*/
- read_limit = tg->bps[READ][LIMIT_LOW] || tg->iops[READ][LIMIT_LOW];
- write_limit = tg->bps[WRITE][LIMIT_LOW] || tg->iops[WRITE][LIMIT_LOW];
- if (!read_limit && !write_limit)
- return true;
- if (read_limit && sq->nr_queued[READ] &&
- (!write_limit || sq->nr_queued[WRITE]))
- return true;
- if (write_limit && sq->nr_queued[WRITE] &&
- (!read_limit || sq->nr_queued[READ]))
+ return !limit || sq->nr_queued[rw];
+}
+
+static bool throtl_tg_can_upgrade(struct throtl_grp *tg)
+{
+ /*
+ * cgroup reaches low limit when low limit of READ and WRITE are
+ * both reached, it's ok to upgrade to next limit if cgroup reaches
+ * low limit
+ */
+ if (throtl_low_limit_reached(tg, READ) &&
+ throtl_low_limit_reached(tg, WRITE))
return true;
if (time_after_eq(jiffies,