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From: Richard Kennedy <richard@rsk.demon.co.uk>
To: Tejun Heo <tj@kernel.org>
Cc: lkml <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: [PATCH] stop_machine: struct cpu_stopper, remove alignment padding on 64 bits
Date: Thu, 05 Aug 2010 12:11:57 +0100	[thread overview]
Message-ID: <1281006717.2000.12.camel@castor.rsk> (raw)

Reorder elements in structure cpu_stopper to remove alignment padding on
64 bit builds, this shrinks its size from 40 to 32 bytes saving 8 bytes
per cpu.

Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
---
patch against 2.6.35
compiled & tested on x86_64

regards
Richard


diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c
index 70f8d90..4372ccb 100644
--- a/kernel/stop_machine.c
+++ b/kernel/stop_machine.c
@@ -35,9 +35,9 @@ struct cpu_stop_done {
 /* the actual stopper, one per every possible cpu, enabled on online cpus */
 struct cpu_stopper {
 	spinlock_t		lock;
+	bool			enabled;	/* is this stopper enabled? */
 	struct list_head	works;		/* list of pending works */
 	struct task_struct	*thread;	/* stopper thread */
-	bool			enabled;	/* is this stopper enabled? */
 };
 
 static DEFINE_PER_CPU(struct cpu_stopper, cpu_stopper);



             reply	other threads:[~2010-08-05 11:31 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-05 11:11 Richard Kennedy [this message]
2010-08-05 11:39 ` [PATCH] stop_machine: struct cpu_stopper, remove alignment padding on 64 bits Tejun Heo
2010-08-05 11:40 ` Peter Zijlstra
2010-08-05 11:44   ` Tejun Heo

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