Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 85b6bc9d authored Aug 18, 2015 by Tejun Heo Committed by Jens Axboe Aug 18, 2015

blkcg: move root blkg lookup optimization from throtl_lookup_tg() to __blkg_lookup()



Currently, both throttle and cfq policies implement their own root
blkg (blkcg_gq) lookup fast path.  This patch moves root blkg
optimization from throtl_lookup_tg() to __blkg_lookup().  cfq-iosched
currently doesn't use blkg_lookup() but will be converted and drop the
optimization too.

Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Cc: Arianna Avanzini <avanzini.arianna@gmail.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

parent 24f29046

block/blk-throttle.c

+0 −7

Original line number	Diff line number	Diff line
		@@ -452,13 +452,6 @@ static void throtl_pd_reset_stats(struct blkg_policy_data *pd)
		static struct throtl_grp throtl_lookup_tg(struct throtl_data td,
		struct blkcg *blkcg)
		{
		/*
		* This is the common case when there are no blkcgs. Avoid lookup
		* in this case
		*/
		if (blkcg == &blkcg_root)
		return td_root_tg(td);

		return blkg_to_tg(blkg_lookup(blkcg, td->queue));
		}

include/linux/blk-cgroup.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -249,6 +249,9 @@ static inline struct blkcg_gq __blkg_lookup(struct blkcg blkcg,
		{
		struct blkcg_gq *blkg;

		if (blkcg == &blkcg_root)
		return q->root_blkg;

		blkg = rcu_dereference(blkcg->blkg_hint);
		if (blkg && blkg->q == q)
		return blkg;