Tejun, I do not have another iteration of the patch yet. we have two customers who reported this problem. One of them has not responded to requests to test a/any patch and other one is not able to recreate this with the latest release. And I am not able to recreate this problem on my own but working on a setup. So if you have any patch, I would be happy to test/deploy it on a first setup I can get hold of.
I was also trying to figure out whether this is some refcounting issue or not since I was thinking that put by anybody other than blk_cleanup_queue() should not result on freeing/blk_release_queue() i.e. put by blk_cleanup_queue() should always be the last put. Regards, Shirish On Fri, Jul 4, 2014 at 12:18 PM, Tejun Heo <t...@kernel.org> wrote: > 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/
