From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933557Ab3CRVhG (ORCPT ); Mon, 18 Mar 2013 17:37:06 -0400 Received: from e8.ny.us.ibm.com ([32.97.182.138]:58285 "EHLO e8.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933108Ab3CRVhA (ORCPT ); Mon, 18 Mar 2013 17:37:00 -0400 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, edumazet@google.com, darren@dvhart.com, fweisbec@gmail.com, sbw@mit.edu, "Paul E. McKenney" , "Paul E. McKenney" Subject: [PATCH tip/core/rcu 10/15] rcu: Rearrange locking in rcu_start_gp() Date: Mon, 18 Mar 2013 14:36:45 -0700 Message-Id: <1363642610-21390-10-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.1.5 In-Reply-To: <1363642610-21390-1-git-send-email-paulmck@linux.vnet.ibm.com> References: <20130318213608.GA20296@linux.vnet.ibm.com> <1363642610-21390-1-git-send-email-paulmck@linux.vnet.ibm.com> X-TM-AS-MML: No X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13031821-9360-0000-0000-000011602006 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: "Paul E. McKenney" If CPUs are to give prior notice of needed grace periods, it will be necessary to invoke rcu_start_gp() without dropping the root rcu_node structure's ->lock. This commit takes a first step in this direction by moving the release of this lock to the end of rcu_start_gp(). Signed-off-by: Paul E. McKenney Signed-off-by: Paul E. McKenney --- kernel/rcutree.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 7b1d776..2c6a931 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -1521,16 +1521,14 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } - rsp->gp_flags = RCU_GP_FLAG_INIT; - raw_spin_unlock(&rnp->lock); /* Interrupts remain disabled. */ /* Ensure that CPU is aware of completion of last grace period. */ - rcu_process_gp_end(rsp, rdp); - local_irq_restore(flags); + __rcu_process_gp_end(rsp, rdp->mynode, rdp); /* Wake up rcu_gp_kthread() to start the grace period. */ wake_up(&rsp->gp_wq); + raw_spin_unlock_irqrestore(&rnp->lock, flags); } /* -- 1.8.1.5