Messages in this thread | | | Date | Thu, 2 Feb 2012 12:33:52 -0800 | From | Tejun Heo <> | Subject | Re: [PATCH 01/11] blkcg: let blkio_group point to blkio_cgroup directly |
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Hello,
On Thu, Feb 02, 2012 at 03:03:18PM -0500, Vivek Goyal wrote: > > +static void blkiocg_destroy(struct cgroup_subsys *subsys, struct cgroup *cgroup) > > +{ > > + struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup); > > + > > if (blkcg != &blkio_root_cgroup) > > kfree(blkcg); > > What makes sure that all the blkg are gone and they have dropped their > reference to blkcg? IIUC, pre-destroy will just make sure to decouple > blkg from request queue as well as blkcg list and also drop joint cgroup > and request queue reference. > > But there could well be some IO queued in the group which might have > its own reference and will be dropped later when IO completes. So at > the time of blkiocg_destroy() it is not guranteed that there are > no reference holders to blkcg?
Yeah, and that would wait till all css refs held by blkgs are gone, right?
-- tejun
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