From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
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, dvhltc@us.ibm.com, niv@us.ibm.com,
tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org,
Valdis.Kletnieks@vt.edu, dhowells@redhat.com,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 2/2] rcu: simplify association of forced quiescent states with grace periods
Date: Thu, 12 Nov 2009 22:35:04 -0800 [thread overview]
Message-ID: <12580941042308-git-send-email-> (raw)
In-Reply-To: <20091113063439.GA560@linux.vnet.ibm.com>
From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
The force_quiescent_state() function also took a snapshot
of the ->completed field, which was as obnoxious as it was in
rcu_sched_qs() and friends. So snapshot ->gpnum-1. Also, since the
dyntick_record_completed() and dyntick_recall_completed() functions are
now simple assignments that are independent of CONFIG_NO_HZ, and since
their names are now misleading, get rid of them.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
kernel/rcutree.c | 27 +++------------------------
1 files changed, 3 insertions(+), 24 deletions(-)
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 0490371..f93f0e2 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -178,29 +178,9 @@ static struct rcu_node *rcu_get_root(struct rcu_state *rsp)
return &rsp->node[0];
}
-/*
- * Record the specified "completed" value, which is later used to validate
- * dynticks counter manipulations and CPU-offline checks. Specify
- * "rsp->completed - 1" to unconditionally invalidate any future dynticks
- * manipulations and CPU-offline checks. Such invalidation is useful at
- * the beginning of a grace period.
- */
-static void dyntick_record_completed(struct rcu_state *rsp, long comp)
-{
- rsp->completed_fqs = comp;
-}
-
#ifdef CONFIG_SMP
/*
- * Recall the previously recorded value of the completion for dynticks.
- */
-static long dyntick_recall_completed(struct rcu_state *rsp)
-{
- return rsp->completed_fqs;
-}
-
-/*
* If the specified CPU is offline, tell the caller that it is in
* a quiescent state. Otherwise, whack it with a reschedule IPI.
* Grace periods can end up waiting on an offline CPU when that
@@ -702,7 +682,6 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags)
rsp->signaled = RCU_GP_INIT; /* Hold off force_quiescent_state. */
rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS;
record_gp_stall_check_time(rsp);
- dyntick_record_completed(rsp, rsp->completed - 1);
/* Special-case the common single-level case. */
if (NUM_RCU_NODES == 1) {
@@ -1201,7 +1180,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
goto unlock_ret; /* no emergency and done recently. */
rsp->n_force_qs++;
spin_lock(&rnp->lock);
- lastcomp = rsp->completed;
+ lastcomp = rsp->gpnum - 1;
signaled = rsp->signaled;
rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS;
if (lastcomp == rsp->gpnum) {
@@ -1235,7 +1214,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
if (lastcomp == rsp->completed &&
rsp->signaled == signaled) {
rsp->signaled = RCU_FORCE_QS;
- dyntick_record_completed(rsp, lastcomp);
+ rsp->completed_fqs = lastcomp;
forcenow = signaled == RCU_SAVE_COMPLETED;
}
spin_unlock(&rnp->lock);
@@ -1246,7 +1225,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
case RCU_FORCE_QS:
/* Check dyntick-idle state, send IPI to laggarts. */
- if (rcu_process_dyntick(rsp, dyntick_recall_completed(rsp),
+ if (rcu_process_dyntick(rsp, rsp->completed_fqs,
rcu_implicit_dynticks_qs))
goto unlock_ret;
--
1.5.2.5
next prev parent reply other threads:[~2009-11-13 6:34 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-13 6:34 [PATCH tip/core/rcu 0/2] rcu: further grace-period processing cleanups Paul E. McKenney
2009-11-13 6:35 ` [PATCH tip/core/rcu 1/2] rcu: accelerate callback processing on CPUs not detecting GP end Paul E. McKenney
2009-11-13 9:31 ` [tip:core/rcu] rcu: Accelerate " tip-bot for Paul E. McKenney
2009-11-13 6:35 ` Paul E. McKenney [this message]
2009-11-13 9:31 ` [tip:core/rcu] rcu: Simplify association of forced quiescent states with grace periods tip-bot for Paul E. McKenney
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