From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752947AbbJFQhG (ORCPT ); Tue, 6 Oct 2015 12:37:06 -0400 Received: from e36.co.us.ibm.com ([32.97.110.154]:38949 "EHLO e36.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752415AbbJFQ3r (ORCPT ); Tue, 6 Oct 2015 12:29:47 -0400 X-IBM-Helo: d03dlp01.boulder.ibm.com X-IBM-MailFrom: paulmck@linux.vnet.ibm.com X-IBM-RcptTo: linux-kernel@vger.kernel.org From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@efficios.com, josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com, dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com, bobby.prani@gmail.com, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 06/18] rcu: Rename qs_pending to core_needs_qs Date: Tue, 6 Oct 2015 09:29:25 -0700 Message-Id: <1444148977-14108-6-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 2.5.2 In-Reply-To: <1444148977-14108-1-git-send-email-paulmck@linux.vnet.ibm.com> References: <20151006162907.GA12020@linux.vnet.ibm.com> <1444148977-14108-1-git-send-email-paulmck@linux.vnet.ibm.com> X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 15100616-0021-0000-0000-0000136ED18E Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org An upcoming commit needs to invert the sense of the ->passed_quiesce rcu_data structure field, so this commit is taking this opportunity to clarify things a bit by renaming ->qs_pending to ->core_needs_qs. So if !rdp->core_needs_qs, then this CPU need not concern itself with quiescent states, in particular, it need not acquire its leaf rcu_node structure's ->lock to check. Otherwise, it needs to report the next quiescent state. Signed-off-by: Paul E. McKenney --- kernel/rcu/tree.c | 14 +++++++------- kernel/rcu/tree.h | 4 ++-- kernel/rcu/tree_plugin.h | 2 +- kernel/rcu/tree_trace.c | 4 ++-- 4 files changed, 12 insertions(+), 12 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index d2cdcada6fe0..7c158ffc7769 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1746,7 +1746,7 @@ static bool __note_gp_changes(struct rcu_state *rsp, struct rcu_node *rnp, trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("cpustart")); rdp->passed_quiesce = 0; rdp->rcu_qs_ctr_snap = __this_cpu_read(rcu_qs_ctr); - rdp->qs_pending = !!(rnp->qsmask & rdp->grpmask); + rdp->core_needs_qs = !!(rnp->qsmask & rdp->grpmask); zero_cpu_stall_ticks(rdp); WRITE_ONCE(rdp->gpwrap, false); } @@ -2357,7 +2357,7 @@ rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp) if ((rnp->qsmask & mask) == 0) { raw_spin_unlock_irqrestore(&rnp->lock, flags); } else { - rdp->qs_pending = 0; + rdp->core_needs_qs = 0; /* * This GP can't end until cpu checks in, so all of our @@ -2388,7 +2388,7 @@ rcu_check_quiescent_state(struct rcu_state *rsp, struct rcu_data *rdp) * Does this CPU still need to do its part for current grace period? * If no, return and let the other CPUs do their part as well. */ - if (!rdp->qs_pending) + if (!rdp->core_needs_qs) return; /* @@ -3828,10 +3828,10 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp) /* Is the RCU core waiting for a quiescent state from this CPU? */ if (rcu_scheduler_fully_active && - rdp->qs_pending && !rdp->passed_quiesce && + rdp->core_needs_qs && !rdp->passed_quiesce && rdp->rcu_qs_ctr_snap == __this_cpu_read(rcu_qs_ctr)) { - rdp->n_rp_qs_pending++; - } else if (rdp->qs_pending && + rdp->n_rp_core_needs_qs++; + } else if (rdp->core_needs_qs && (rdp->passed_quiesce || rdp->rcu_qs_ctr_snap != __this_cpu_read(rcu_qs_ctr))) { rdp->n_rp_report_qs++; @@ -4157,7 +4157,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp) rdp->completed = rnp->completed; rdp->passed_quiesce = false; rdp->rcu_qs_ctr_snap = per_cpu(rcu_qs_ctr, cpu); - rdp->qs_pending = false; + rdp->core_needs_qs = false; trace_rcu_grace_period(rsp->name, rdp->gpnum, TPS("cpuonl")); raw_spin_unlock_irqrestore(&rnp->lock, flags); } diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index efe361c764ab..4a0f30676ba8 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -303,7 +303,7 @@ struct rcu_data { unsigned long rcu_qs_ctr_snap;/* Snapshot of rcu_qs_ctr to check */ /* for rcu_all_qs() invocations. */ bool passed_quiesce; /* User-mode/idle loop etc. */ - bool qs_pending; /* Core waits for quiesc state. */ + bool core_needs_qs; /* Core waits for quiesc state. */ bool beenonline; /* CPU online at least once. */ bool gpwrap; /* Possible gpnum/completed wrap. */ struct rcu_node *mynode; /* This CPU's leaf of hierarchy */ @@ -368,7 +368,7 @@ struct rcu_data { /* 5) __rcu_pending() statistics. */ unsigned long n_rcu_pending; /* rcu_pending() calls since boot. */ - unsigned long n_rp_qs_pending; + unsigned long n_rp_core_needs_qs; unsigned long n_rp_report_qs; unsigned long n_rp_cb_ready; unsigned long n_rp_cpu_needs_gp; diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 6f7500f9387c..e33b4f3b8e0a 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -619,7 +619,7 @@ static void rcu_preempt_check_callbacks(void) return; } if (t->rcu_read_lock_nesting > 0 && - __this_cpu_read(rcu_data_p->qs_pending) && + __this_cpu_read(rcu_data_p->core_needs_qs) && !__this_cpu_read(rcu_data_p->passed_quiesce)) t->rcu_read_unlock_special.b.need_qs = true; } diff --git a/kernel/rcu/tree_trace.c b/kernel/rcu/tree_trace.c index 6fc4c5ff3bb5..4ac25f8520d6 100644 --- a/kernel/rcu/tree_trace.c +++ b/kernel/rcu/tree_trace.c @@ -123,7 +123,7 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp) ulong2long(rdp->completed), ulong2long(rdp->gpnum), rdp->passed_quiesce, rdp->rcu_qs_ctr_snap == per_cpu(rcu_qs_ctr, rdp->cpu), - rdp->qs_pending); + rdp->core_needs_qs); seq_printf(m, " dt=%d/%llx/%d df=%lu", atomic_read(&rdp->dynticks->dynticks), rdp->dynticks->dynticks_nesting, @@ -361,7 +361,7 @@ static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp) cpu_is_offline(rdp->cpu) ? '!' : ' ', rdp->n_rcu_pending); seq_printf(m, "qsp=%ld rpq=%ld cbr=%ld cng=%ld ", - rdp->n_rp_qs_pending, + rdp->n_rp_core_needs_qs, rdp->n_rp_report_qs, rdp->n_rp_cb_ready, rdp->n_rp_cpu_needs_gp); -- 2.5.2