Messages in this thread Patch in this message | | | From | Tejun Heo <> | Subject | [PATCH 03/10] blkcg: move root blkg lookup optimization from throtl_lookup_tg() to __blkg_lookup() | Date | Sun, 12 Jul 2015 14:00:36 -0400 |
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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> --- block/blk-throttle.c | 7 ------- include/linux/blk-cgroup.h | 3 +++ 2 files changed, 3 insertions(+), 7 deletions(-)
diff --git a/block/blk-throttle.c b/block/blk-throttle.c index c2c7547..1f63fc8 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -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)); } diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h index d5b54aa..0609bce 100644 --- a/include/linux/blk-cgroup.h +++ b/include/linux/blk-cgroup.h @@ -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; -- 2.4.3
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