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| author | Dennis Zhou <dennis@kernel.org> | 2018-12-05 12:10:28 -0500 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-12-07 22:26:36 -0700 |
| commit | beea9da07d8a6228a7e4a31a83f9478d513bf03f (patch) | |
| tree | 263661b03b835c4715fbeb97c2bdbd0331233001 /block/blk-throttle.c | |
| parent | b978962ad4f7f9c06e5aa07b2a9b22f6d600456c (diff) | |
| download | lwn-beea9da07d8a6228a7e4a31a83f9478d513bf03f.tar.gz lwn-beea9da07d8a6228a7e4a31a83f9478d513bf03f.zip | |
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-throttle.c')
| -rw-r--r-- | block/blk-throttle.c | 4 |
1 files changed, 1 insertions, 3 deletions
diff --git a/block/blk-throttle.c b/block/blk-throttle.c index 8f0a104770ee..d648d6720f46 100644 --- a/block/blk-throttle.c +++ b/block/blk-throttle.c @@ -2118,9 +2118,7 @@ static inline void throtl_update_latency_buckets(struct throtl_data *td) static void blk_throtl_assoc_bio(struct throtl_grp *tg, struct bio *bio) { #ifdef CONFIG_BLK_DEV_THROTTLING_LOW - /* fallback to root_blkg if we fail to get a blkg ref */ - if (bio->bi_css && (bio_associate_blkg(bio, tg_to_blkg(tg)) == -ENODEV)) - bio_associate_blkg(bio, bio->bi_disk->queue->root_blkg); + bio_associate_blkg(bio, tg_to_blkg(tg)); bio_issue_init(&bio->bi_issue, bio_sectors(bio)); #endif } |