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From: Richard Kennedy <>
To: Ingo Molnar <>
Cc: Peter Zijlstra <>,
	lkml <>
Subject: [PATCH] sched: reorder root_domain to remove 64 bit alignment padding
Date: Fri, 15 Jul 2011 11:41:31 +0100
Message-ID: <1310726492.1977.5.camel@castor.rsk> (raw)

Reorder root_domain to remove 8 bytes of alignment padding on 64 bit
builds, this shrinks the size from 1736 to 1728 bytes, therefore using
one fewer cachelines.

Signed-off-by: Richard Kennedy <>

patch against v3.0-rc7

compiled & booted on x86_64.

I've been running this patch for 2 days without any obvious problems,
but I don't have any specific RT test cases.


diff --git a/kernel/sched.c b/kernel/sched.c
index 9769c75..4ecf9db 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -422,6 +422,7 @@ struct rt_rq {
 struct root_domain {
 	atomic_t refcount;
+	atomic_t rto_count;
 	struct rcu_head rcu;
 	cpumask_var_t span;
 	cpumask_var_t online;
@@ -431,7 +432,6 @@ struct root_domain {
 	 * one runnable RT task.
 	cpumask_var_t rto_mask;
-	atomic_t rto_count;
 	struct cpupri cpupri;

             reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-07-15 10:41 Richard Kennedy [this message]
2011-07-15 10:44 ` Peter Zijlstra
2011-07-15 11:23   ` Richard Kennedy
2011-07-15 18:59     ` Henrique de Moraes Holschuh
2011-07-21 18:30 ` [tip:sched/core] sched: Reorder " tip-bot for Richard Kennedy

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