Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]


Groups > linux.kernel > #1287996

[PATCH v2 tip/core/rcu 02/11] rcu: Clarify role of ->expmaskinitnext

Path csiph.com!goblin1!goblin.stu.neva.ru!feeds.phibee-telecom.net!news.panservice.it!bofh.it!news.nic.it!robomod
From "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Newsgroups linux.kernel
Subject [PATCH v2 tip/core/rcu 02/11] rcu: Clarify role of ->expmaskinitnext
Date Thu, 10 Dec 2015 00:10:04 +0100
Message-ID <qDW20-6ob-67@gated-at.bofh.it> (permalink)
References <qDW1Y-6ob-11@gated-at.bofh.it>
X-Original-To linux-kernel@vger.kernel.org
X-Ibm-Helo d03dlp02.boulder.ibm.com
X-Ibm-Mailfrom paulmck@linux.vnet.ibm.com
X-Ibm-Rcptto linux-kernel@vger.kernel.org
X-Mailer git-send-email 2.5.2
X-Tm-As-Mml disable
X-Content-Scanned Fidelis XPS MAILER
X-Cbid 15120923-0025-0000-0000-00001F6D7274
Sender robomod@news.nic.it
List-ID <linux-kernel.vger.kernel.org>
X-Mailing-List linux-kernel@vger.kernel.org
Approved robomod@news.nic.it
Lines 32
Organization linux.* mail to news gateway
X-Original-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" <paulmck@linux.vnet.ibm.com>
X-Original-Date Wed, 9 Dec 2015 15:02:59 -0800
X-Original-Message-ID <1449702188-493-2-git-send-email-paulmck@linux.vnet.ibm.com>
X-Original-References <20151209230243.GA32518@linux.vnet.ibm.com>
X-Original-Sender linux-kernel-owner@vger.kernel.org
Xref csiph.com linux.kernel:1287996

Show key headers only | View raw


Analogy with the ->qsmaskinitnext field might lead one to believe that
->expmaskinitnext tracks online CPUs.  This belief is incorrect: Any CPU
that has ever been online will have its bit set in the ->expmaskinitnext
field.  This commit therefore adds a comment to make this clear, at
least to people who read comments.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
 kernel/rcu/tree.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index f32bebb6bc90..8151971a8978 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -178,6 +178,8 @@ struct rcu_node {
 				/*  beginning of each expedited GP. */
 	unsigned long expmaskinitnext;
 				/* Online CPUs for next expedited GP. */
+				/*  Any CPU that has ever been online will */
+				/*  have its bit set. */
 	unsigned long grpmask;	/* Mask to apply to parent qsmask. */
 				/*  Only one bit will be set in this mask. */
 	int	grplo;		/* lowest-numbered CPU or group here. */
-- 
2.5.2

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Back to linux.kernel | Previous | Next | Find similar | Unroll thread


Thread

[PATCH v2 tip/core/rcu 02/11] rcu: Clarify role of ->expmaskinitnext "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2015-12-10 00:10 +0100

csiph-web