diff options
| author |   Christoph Hellwig <hch@lst.de> | 2022-09-27 08:54:25 +0200 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2022-09-27 11:50:05 -0600 |
| commit | 5765033cf77c54897848df683420bb62b6cc3d05 (patch) | |
| tree | 15ae842e84983808842f3b1ad47397093d3a7370 | |
| parent | blk-mq: use quiesced elevator switch when reinitializing queues (diff) | |
| download | linux-dev-5765033cf77c54897848df683420bb62b6cc3d05.tar.xz linux-dev-5765033cf77c54897848df683420bb62b6cc3d05.zip | |
blk-cgroup: don't update the blkg lookup hint in blkg_conf_prep
blkg_conf_prep just creates a new blkg structure, there is no real
need to update the lookup hint which should only be done on a
successful lookup in the I/O path.
Suggested-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Tejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20220927065425.257876-1-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | block/blk-cgroup.c | 17 |
1 files changed, 4 insertions, 13 deletions
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c index 94af5f3f3620..6a5c849ee061 100644 --- a/block/blk-cgroup.c +++ b/block/blk-cgroup.c @@ -263,14 +263,6 @@ err_free: return NULL; } -static void blkg_update_hint(struct blkcg *blkcg, struct blkcg_gq *blkg) -{ - lockdep_assert_held(&blkg->q->queue_lock); - - if (blkcg != &blkcg_root && blkg != rcu_dereference(blkcg->blkg_hint)) - rcu_assign_pointer(blkcg->blkg_hint, blkg); -} - /* * If @new_blkg is %NULL, this function tries to allocate a new one as * necessary using %GFP_NOWAIT. @new_blkg is always consumed on return. @@ -383,7 +375,9 @@ static struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg, spin_lock_irqsave(&q->queue_lock, flags); blkg = blkg_lookup(blkcg, q); if (blkg) { - blkg_update_hint(blkcg, blkg); + if (blkcg != &blkcg_root && + blkg != rcu_dereference(blkcg->blkg_hint)) + rcu_assign_pointer(blkcg->blkg_hint, blkg); goto found; } @@ -680,10 +674,8 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, } blkg = blkg_lookup(blkcg, q); - if (blkg) { - blkg_update_hint(blkcg, blkg); + if (blkg) goto success; - } /* * Create blkgs walking down from blkcg_root to @blkcg, so that all @@ -727,7 +719,6 @@ int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol, blkg = blkg_lookup(pos, q); if (blkg) { - blkg_update_hint(pos, blkg); blkg_free(new_blkg); } else { blkg = blkg_create(pos, disk, new_blkg); |