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authorDennis Zhou <dennis@kernel.org>2018-12-05 20:10:28 +0300
committerJens Axboe <axboe@kernel.dk>2018-12-08 08:26:36 +0300
commitbeea9da07d8a6228a7e4a31a83f9478d513bf03f (patch)
tree263661b03b835c4715fbeb97c2bdbd0331233001 /block/blk-iolatency.c
parentb978962ad4f7f9c06e5aa07b2a9b22f6d600456c (diff)
downloadlinux-beea9da07d8a6228a7e4a31a83f9478d513bf03f.tar.xz
blkcg: convert blkg_lookup_create() to find closest blkg
There are several scenarios where blkg_lookup_create() can fail such as the blkcg dying, request_queue is dying, or simply being OOM. Most handle this by simply falling back to the q->root_blkg and calling it a day. This patch implements the notion of closest blkg. During blkg_lookup_create(), if it fails to create, return the closest blkg found or the q->root_blkg. blkg_try_get_closest() is introduced and used during association so a bio is always attached to a blkg. Signed-off-by: Dennis Zhou <dennis@kernel.org> Acked-by: Tejun Heo <tj@kernel.org> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-iolatency.c')
-rw-r--r--block/blk-iolatency.c14
1 files changed, 2 insertions, 12 deletions
diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c
index e6f68f15dee9..46e86c34cf79 100644
--- a/block/blk-iolatency.c
+++ b/block/blk-iolatency.c
@@ -483,21 +483,11 @@ static void blkcg_iolatency_throttle(struct rq_qos *rqos, struct bio *bio)
rcu_read_lock();
bio_associate_blkcg(bio, NULL);
blkcg = bio_blkcg(bio);
- blkg = blkg_lookup(blkcg, q);
- if (unlikely(!blkg)) {
- spin_lock_irq(&q->queue_lock);
- blkg = __blkg_lookup_create(blkcg, q);
- if (IS_ERR(blkg))
- blkg = NULL;
- spin_unlock_irq(&q->queue_lock);
- }
- if (!blkg)
- goto out;
-
+ blkg = blkg_lookup_create(blkcg, q);
bio_issue_init(&bio->bi_issue, bio_sectors(bio));
bio_associate_blkg(bio, blkg);
-out:
rcu_read_unlock();
+
while (blkg && blkg->parent) {
struct iolatency_grp *iolat = blkg_to_lat(blkg);
if (!iolat) {