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From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: akpm@linux-foundation.org
Cc: kosaki.motohiro@gmail.com, linux-kernel@vger.kernel.org,
	venki@google.com, rusty@rustcorp.com.au
Subject: [PATCH] lib/cpumask.c: Optimize __any_online_cpu() calculation
Date: Wed, 15 Feb 2012 18:05:14 +0530	[thread overview]
Message-ID: <20120215123208.15623.73499.stgit@srivatsabhat.in.ibm.com> (raw)

__any_online_cpu() uses a for loop at the moment.
Instead, use cpumask_* operations to speed it up.

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
---
Actually, the patch posted at https://lkml.org/lkml/2012/2/15/101 removed
the last user of any_online_cpu() (and hence __any_online_cpu()).
However, since this is an exported symbol, I refrained from removing this
function altogether.

 lib/cpumask.c |    8 +-------
 1 files changed, 1 insertions(+), 7 deletions(-)

diff --git a/lib/cpumask.c b/lib/cpumask.c
index af3e5817..b25f53d 100644
--- a/lib/cpumask.c
+++ b/lib/cpumask.c
@@ -28,13 +28,7 @@ EXPORT_SYMBOL(__next_cpu_nr);
 
 int __any_online_cpu(const cpumask_t *mask)
 {
-	int cpu;
-
-	for_each_cpu(cpu, mask) {
-		if (cpu_online(cpu))
-			break;
-	}
-	return cpu;
+	return cpumask_any_and(mask, cpu_online_mask);
 }
 EXPORT_SYMBOL(__any_online_cpu);
 


             reply	other threads:[~2012-02-15 12:35 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-15 12:35 Srivatsa S. Bhat [this message]
2012-02-15 12:57 ` Eric Dumazet
2012-02-15 14:19   ` Srivatsa S. Bhat
2012-02-15 22:51     ` Rusty Russell
2012-02-17 12:19       ` Srivatsa S. Bhat

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