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| author |   Tejun Heo <tj@kernel.org> | 2019-06-27 13:39:52 -0700 |
|---|---|---|
| committer |   Jens Axboe <axboe@kernel.dk> | 2019-07-10 09:00:57 -0600 |
| commit | d3f77dfdc71835f8db71ca57d272b1fbec9dfc18 (patch) | |
| tree | ced59cee416b39c3c2f80c647c736a2d378772e3 /block/blk-core.c | |
| parent | blkcg, writeback: Implement wbc_blkcg_css() (diff) | |
| download | linux-dev-d3f77dfdc71835f8db71ca57d272b1fbec9dfc18.tar.xz linux-dev-d3f77dfdc71835f8db71ca57d272b1fbec9dfc18.zip | |
blkcg: implement REQ_CGROUP_PUNT
When a shared kthread needs to issue a bio for a cgroup, doing so
synchronously can lead to priority inversions as the kthread can be
trapped waiting for that cgroup. This patch implements
REQ_CGROUP_PUNT flag which makes submit_bio() punt the actual issuing
to a dedicated per-blkcg work item to avoid such priority inversions.
This will be used to fix priority inversions in btrfs compression and
should be generally useful as we grow filesystem support for
comprehensive IO control.
Cc: Chris Mason <clm@fb.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block/blk-core.c')
| -rw-r--r-- | block/blk-core.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/block/blk-core.c b/block/blk-core.c index edd009213f5b..260e36a2c343 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -1128,6 +1128,9 @@ EXPORT_SYMBOL_GPL(direct_make_request); */ blk_qc_t submit_bio(struct bio *bio) { + if (blkcg_punt_bio_submit(bio)) + return BLK_QC_T_NONE; + /* * If it's a regular read/write or a barrier with data attached, * go through the normal accounting stuff before submission. |