diff options
| -rw-r--r-- | block/blk-cgroup.h | 17 | ||||
| -rw-r--r-- | block/blk-merge.c | 11 |
2 files changed, 28 insertions, 0 deletions
diff --git a/block/blk-cgroup.h b/block/blk-cgroup.h index 3e91803c4a55..47e1e38390c9 100644 --- a/block/blk-cgroup.h +++ b/block/blk-cgroup.h @@ -15,6 +15,7 @@ */ #include <linux/blk-cgroup.h> +#include <linux/blk-mq.h> /* percpu_counter batch for blkg_[rw]stats, per-cpu drift doesn't matter */ #define BLKG_STAT_CPU_BATCH (INT_MAX / 2) @@ -428,6 +429,21 @@ static inline void blkcg_clear_delay(struct blkcg_gq *blkg) atomic_dec(&blkg->blkcg->css.cgroup->congestion_count); } +/** + * blk_cgroup_mergeable - Determine whether to allow or disallow merges + * @rq: request to merge into + * @bio: bio to merge + * + * @bio and @rq should belong to the same cgroup and their issue_as_root should + * match. The latter is necessary as we don't want to throttle e.g. a metadata + * update because it happens to be next to a regular IO. + */ +static inline bool blk_cgroup_mergeable(struct request *rq, struct bio *bio) +{ + return rq->bio->bi_blkg == bio->bi_blkg && + bio_issue_as_root_blkg(rq->bio) == bio_issue_as_root_blkg(bio); +} + void blk_cgroup_bio_start(struct bio *bio); void blkcg_add_delay(struct blkcg_gq *blkg, u64 now, u64 delta); #else /* CONFIG_BLK_CGROUP */ @@ -467,6 +483,7 @@ static inline void blkg_put(struct blkcg_gq *blkg) { } static inline bool blkcg_punt_bio_submit(struct bio *bio) { return false; } static inline void blkcg_bio_issue_init(struct bio *bio) { } static inline void blk_cgroup_bio_start(struct bio *bio) { } +static inline bool blk_cgroup_mergeable(struct request *rq, struct bio *bio) { return true; } #define blk_queue_for_each_rl(rl, q) \ for ((rl) = &(q)->root_rl; (rl); (rl) = NULL) diff --git a/block/blk-merge.c b/block/blk-merge.c index 8d8177f71ebd..ea6968313b4a 100644 --- a/block/blk-merge.c +++ b/block/blk-merge.c @@ -9,6 +9,7 @@ #include <linux/blk-integrity.h> #include <linux/scatterlist.h> #include <linux/part_stat.h> +#include <linux/blk-cgroup.h> #include <trace/events/block.h> @@ -598,6 +599,9 @@ static inline unsigned int blk_rq_get_max_sectors(struct request *rq, static inline int ll_new_hw_segment(struct request *req, struct bio *bio, unsigned int nr_phys_segs) { + if (!blk_cgroup_mergeable(req, bio)) + goto no_merge; + if (blk_integrity_merge_bio(req->q, req, bio) == false) goto no_merge; @@ -694,6 +698,9 @@ static int ll_merge_requests_fn(struct request_queue *q, struct request *req, if (total_phys_segments > blk_rq_get_max_segments(req)) return 0; + if (!blk_cgroup_mergeable(req, next->bio)) + return 0; + if (blk_integrity_merge_rq(q, req, next) == false) return 0; @@ -902,6 +909,10 @@ bool blk_rq_merge_ok(struct request *rq, struct bio *bio) if (bio_data_dir(bio) != rq_data_dir(rq)) return false; + /* don't merge across cgroup boundaries */ + if (!blk_cgroup_mergeable(rq, bio)) + return false; + /* only merge integrity protected bio into ditto rq */ if (blk_integrity_merge_bio(rq->q, rq, bio) == false) return false; |