Messages in this thread | | | Date | Wed, 24 Nov 2010 16:11:34 -0800 | Subject | Re: [PATCH 1/2] cgroup: Set CGRP_RELEASABLE when adding to a cgroup | From | Colin Cross <> |
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On Wed, Nov 24, 2010 at 3:54 PM, Paul Menage <menage@google.com> wrote: > On Tue, Nov 23, 2010 at 9:37 PM, Colin Cross <ccross@android.com> wrote: >> @@ -364,12 +372,8 @@ static void __put_css_set(struct css_set *cg, int taskexit) >> struct cgroup *cgrp = link->cgrp; >> list_del(&link->cg_link_list); >> list_del(&link->cgrp_link_list); >> - if (atomic_dec_and_test(&cgrp->count) && >> - notify_on_release(cgrp)) { >> - if (taskexit) >> - set_bit(CGRP_RELEASABLE, &cgrp->flags); >> + if (atomic_dec_and_test(&cgrp->count)) >> check_for_release(cgrp); >> - } > > We seem to have lost some notify_on_release() checks - maybe move that > to check_for_release()? check_for_release immediately calls cgroup_is_releasable, which checks for the same bit as notify_on_release. There's no need for CGRP_RELEASABLE to depend on notify_on_release, or to check notify_on_release before calling check_for_release.
>> /* Caller must verify that the css is not for root cgroup */ >> +void __css_get(struct cgroup_subsys_state *css, int count) >> +{ >> + atomic_add(count, &css->refcnt); >> + set_bit(CGRP_RELEASABLE, &css->cgroup->flags); >> +} > > Is css_get() the right place to be putting this? It's not clear to me > why a subsystem taking a refcount on a cgroup's state should render it > releasable when it drops that refcount. I matched the existing behavior, __css_put sets CGRP_RELEASABLE when refcnt goes to 0.
> Should we maybe clear the CGRP_RELEASABLE flag right before doing the > userspace callback? Actually, I think CGRP_RELEASABLE can be dropped entirely. check_for_release is only called from __css_put, cgroup_rmdir, and __put_css_set (or free_css_set_work after my second patch). Those all imply that __css_get, get_css_set, or cgroup_create have been previously called, which are the functions that set CGRP_RELEASABLE. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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