Commit acaf523a authored Nov 26, 2020 by Yu Kuai Committed by Jens Axboe Dec 02, 2020

blk-throttle: don't check whether or not lower limit is valid if...


blk-throttle: don't check whether or not lower limit is valid if CONFIG_BLK_DEV_THROTTLING_LOW is off

blk_throtl_update_limit_valid() will search for descendants to see if
'LIMIT_LOW' of bps/iops and READ/WRITE is nonzero. However, they're always
zero if CONFIG_BLK_DEV_THROTTLING_LOW is not set, furthermore, a lot of
time will be wasted to iterate descendants.

Thus do nothing in blk_throtl_update_limit_valid() in such situation.

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent b0d97557

block/blk-throttle.c

+6 −0

Original line number	Diff line number	Diff line
		@@ -587,6 +587,7 @@ static void throtl_pd_online(struct blkg_policy_data *pd)
		tg_update_has_rules(tg);
		}

		#ifdef CONFIG_BLK_DEV_THROTTLING_LOW
		static void blk_throtl_update_limit_valid(struct throtl_data *td)
		{
		struct cgroup_subsys_state *pos_css;
		@@ -607,6 +608,11 @@ static void blk_throtl_update_limit_valid(struct throtl_data *td)

		td->limit_valid[LIMIT_LOW] = low_valid;
		}
		#else
		static inline void blk_throtl_update_limit_valid(struct throtl_data *td)
		{
		}
		#endif

		static void throtl_upgrade_state(struct throtl_data *td);
		static void throtl_pd_offline(struct blkg_policy_data *pd)

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