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 04/11] rcu: eliminate local variable signaled from force_quiescent_state()
Date: Mon, 4 Jan 2010 15:09:03 -0800 [thread overview]
Message-ID: <1262646550602-git-send-email-> (raw)
In-Reply-To: <20100104230850.GA22111@linux.vnet.ibm.com>
From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Because the root rcu_node lock is held across entry to the switch
statement in force_quiescent_state(), it is no longer necessary
to snapshot rsp->signaled to a local variable. Eliminate both the
snapshotting and the local variable.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
kernel/rcutree.c | 9 +++------
1 files changed, 3 insertions(+), 6 deletions(-)
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 41688ff..1d8cfb1 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1193,7 +1193,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
unsigned long flags;
long lastcomp;
struct rcu_node *rnp = rcu_get_root(rsp);
- u8 signaled;
u8 forcenow;
u8 gpdone;
@@ -1209,7 +1208,6 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
rsp->n_force_qs++;
spin_lock(&rnp->lock); /* irqs already disabled */
lastcomp = rsp->gpnum - 1;
- signaled = rsp->signaled;
rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS;
if(!rcu_gp_in_progress(rsp)) {
rsp->n_force_qs_ngp++;
@@ -1217,7 +1215,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
goto unlock_fqs_ret; /* no GP in progress, time updated. */
}
rsp->fqs_active = 1;
- switch (signaled) {
+ switch (rsp->signaled) {
case RCU_GP_IDLE:
case RCU_GP_INIT:
@@ -1242,11 +1240,10 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
/* Update state, record completion counter. */
forcenow = 0;
if (lastcomp + 1 == rsp->gpnum &&
- lastcomp == rsp->completed &&
- rsp->signaled == signaled) {
+ lastcomp == rsp->completed) {
+ forcenow = rsp->signaled == RCU_SAVE_COMPLETED;
rsp->signaled = RCU_FORCE_QS;
rsp->completed_fqs = lastcomp;
- forcenow = signaled == RCU_SAVE_COMPLETED;
}
if (!forcenow)
break;
--
1.5.2.5
next prev parent reply other threads:[~2010-01-04 23:11 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-01-04 23:08 [PATCH tip/core/rcu 0/11] rcu: suppress GP start to simplify force_quiescent_state() Paul E. McKenney
2010-01-04 23:09 ` [PATCH tip/core/rcu 01/11] rcu: adjust force_quiescent_state() locking, step 1 Paul E. McKenney
2010-01-13 10:24 ` [tip:core/rcu] rcu: Adjust " tip-bot for Paul E. McKenney
2010-01-04 23:09 ` [PATCH tip/core/rcu 02/11] rcu: adjust force_quiescent_state() locking, step 2 Paul E. McKenney
2010-01-13 10:25 ` [tip:core/rcu] rcu: Adjust " tip-bot for Paul E. McKenney
2010-01-04 23:09 ` [PATCH tip/core/rcu 03/11] rcu: prohibit starting new grace periods while forcing quiescent states Paul E. McKenney
2010-01-13 10:25 ` [tip:core/rcu] rcu: Prohibit " tip-bot for Paul E. McKenney
2010-01-04 23:09 ` Paul E. McKenney [this message]
2010-01-13 10:25 ` [tip:core/rcu] rcu: Eliminate local variable signaled from force_quiescent_state() tip-bot for Paul E. McKenney
2010-01-04 23:09 ` [PATCH tip/core/rcu 05/11] rcu: eliminate local variable lastcomp " Paul E. McKenney
2010-01-13 10:25 ` [tip:core/rcu] rcu: Eliminate " tip-bot for Paul E. McKenney
2010-01-04 23:09 ` [PATCH tip/core/rcu 06/11] rcu: eliminate second argument of rcu_process_dyntick() Paul E. McKenney
2010-01-13 10:26 ` [tip:core/rcu] rcu: Eliminate " tip-bot for Paul E. McKenney
2010-01-04 23:09 ` [PATCH tip/core/rcu 07/11] rcu: eliminate rcu_process_dyntick() return value Paul E. McKenney
2010-01-13 10:26 ` [tip:core/rcu] rcu: Eliminate " tip-bot for Paul E. McKenney
2010-01-04 23:09 ` [PATCH tip/core/rcu 08/11] rcu: remove leg of force_quiescent_state() switch statement Paul E. McKenney
2010-01-13 10:26 ` [tip:core/rcu] rcu: Remove " tip-bot for Paul E. McKenney
2010-01-04 23:09 ` [PATCH tip/core/rcu 09/11] rcu: remove redundant grace-period check Paul E. McKenney
2010-01-13 10:26 ` [tip:core/rcu] rcu: Remove " tip-bot for Paul E. McKenney
2010-01-04 23:09 ` [PATCH tip/core/rcu 10/11] rcu: make force_quiescent_state() start grace period if needed Paul E. McKenney
2010-01-13 10:27 ` [tip:core/rcu] rcu: Make " tip-bot for Paul E. McKenney
2010-01-04 23:09 ` [PATCH tip/core/rcu 11/11] rcu: add force_quiescent_state() testing to rcutorture Paul E. McKenney
2010-01-13 10:27 ` [tip:core/rcu] rcu: Add " tip-bot for Paul E. McKenney
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1262646550602-git-send-email- \
--to=paulmck@linux.vnet.ibm.com \
--cc=Valdis.Kletnieks@vt.edu \
--cc=akpm@linux-foundation.org \
--cc=dhowells@redhat.com \
--cc=dipankar@in.ibm.com \
--cc=dvhltc@us.ibm.com \
--cc=josh@joshtriplett.org \
--cc=laijs@cn.fujitsu.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mathieu.desnoyers@polymtl.ca \
--cc=mingo@elte.hu \
--cc=niv@us.ibm.com \
--cc=peterz@infradead.org \
--cc=rostedt@goodmis.org \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox