On Tue, Jun 24, 2014 at 05:43:40PM -0400, Tejun Heo wrote: > Hello, > > On Tue, Jun 24, 2014 at 04:37:58PM -0500, Shirish Pargaonkar wrote: > > When we start from blk_cleanup_queue(), we put request queue in bypass mode, > > drain it (and service queues), and then destroy blkcgs (explicitly) > > > > When we start from blk_release_queue(), we do not drain first and then > > destroy blkcgs. So if we destroy blkcg and then call (implicitly) and > > bail out of > > blk_drain_queue, we would not have drained the service queues which > > is not what we want. > > I'm not really following you. What do you mean "when we start from > blk_release_queue()"? blk_release_queue() is called after the last > put which can only follow blk_cleanup_queue() if the queue is fully > initialized. The queue is already in bypass mode and fully drained by > the time control reaches blk_release_queue(). Module [un]load > re-invoking the path doesn't change anything. > > > I do not see any harm in waiting till end to release blkcgs (as I > > understand). > > Well, the harm there is not freeing those blkgs unless all the blkcg > policies are unloaded which is usually never on most systems.
Ping. We have a patch which makes this problem more visible. Are you still planning to re-spin the patch? Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
