The commit is pushed to "branch-rh7-3.10.0-229.7.2-ovz" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git after rh7-3.10.0-229.7.2.vz7.6.3 ------> commit 41721ced765e1156651d31c8b9deb0111340e984 Author: Vladimir Davydov <vdavy...@parallels.com> Date: Fri Aug 28 14:49:22 2015 +0400
ms/percpu-refcount: consistently use plain (non-sched) RCU Patchset description: Pulling upstream patches converting css refcnt to percpu_ref. https://jira.sw.ru/browse/PSBM-34174 Kent Overstreet (2): percpu: implement generic percpu refcounting percpu-refcount: Don't use silly cmpxchg() Tejun Heo (9): percpu-refcount: consistently use plain (non-sched) RCU percpu-refcount: cosmetic updates percpu-refcount: add __must_check to percpu_ref_init() and don't use ACCESS_ONCE() in percpu_ref_kill_rcu() percpu-refcount: implement percpu_ref_cancel_init() percpu-refcount: implement percpu_tryget() along with percpu_ref_kill_and_confirm() percpu-refcount: use RCU-sched insted of normal RCU cgroup: reorder the operations in cgroup_destroy_locked() cgroup: split cgroup destruction into two steps cgroup: use percpu refcnt for cgroup_subsys_states === This patch description: From: Tejun Heo <t...@kernel.org> percpu_ref_get/put() are using preempt_disable/enable() while percpu_ref_kill() is using plain call_rcu() instead of call_rcu_sched(). This is buggy as grace periods of the two may not match. Fix it by using plain RCU in percpu_ref_get/put(). (I suggested using sched RCU in the first place but there's no actual benefit in doing so unless we're gonna introduce different variants of get/put to be called while preemption is alredy disabled, which we definitely shouldn't.) Signed-off-by: Tejun Heo <t...@kernel.org> Reported-by: Rusty Russell <ru...@rustcorp.com.au> Acked-by: Kent Overstreet <koverstr...@google.com> (cherry picked from commit 6a24474da83ea7c8b7d32f05f858b1259994067a) Signed-off-by: Vladimir Davydov <vdavy...@parallels.com> --- include/linux/percpu-refcount.h | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/include/linux/percpu-refcount.h b/include/linux/percpu-refcount.h index 24b31ef..abe1411 100644 --- a/include/linux/percpu-refcount.h +++ b/include/linux/percpu-refcount.h @@ -85,7 +85,7 @@ static inline void percpu_ref_get(struct percpu_ref *ref) { unsigned __percpu *pcpu_count; - preempt_disable(); + rcu_read_lock(); pcpu_count = ACCESS_ONCE(ref->pcpu_count); @@ -94,7 +94,7 @@ static inline void percpu_ref_get(struct percpu_ref *ref) else atomic_inc(&ref->count); - preempt_enable(); + rcu_read_unlock(); } /** @@ -107,7 +107,7 @@ static inline void percpu_ref_put(struct percpu_ref *ref) { unsigned __percpu *pcpu_count; - preempt_disable(); + rcu_read_lock(); pcpu_count = ACCESS_ONCE(ref->pcpu_count); @@ -116,7 +116,7 @@ static inline void percpu_ref_put(struct percpu_ref *ref) else if (unlikely(atomic_dec_and_test(&ref->count))) ref->release(ref); - preempt_enable(); + rcu_read_unlock(); } #endif _______________________________________________ Devel mailing list Devel@openvz.org https://lists.openvz.org/mailman/listinfo/devel