On Thu, Jun 13, 2019 at 05:33:45PM -0700, Tejun Heo wrote: > 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. > > Signed-off-by: Tejun Heo <tj@xxxxxxxxxx> > Cc: Chris Mason <clm@xxxxxx> Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx> Thanks, Josef
