[PATCH 06/23] lib: percpu_counter_set

From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: miklos@szeredi.hu, akpm@linux-foundation.org, neilb@suse.de,
	dgc@sgi.com, tomoki.sekiyama.qu@hitachi.com,
	a.p.zijlstra@chello.nl, nikita@clusterfs.com,
	trond.myklebust@fys.uio.no, yingchao.zhou@gmail.com,
	richard@rsk.demon.co.uk, torvalds@linux-foundation.org
Subject: [PATCH 06/23] lib: percpu_counter_set
Date: Tue, 11 Sep 2007 21:53:56 +0200	[thread overview]
Message-ID: <20070911200012.935811000@chello.nl> (raw)
In-Reply-To: 20070911195350.825778000@chello.nl

[-- Attachment #1: percpu_counter_set.patch --]
[-- Type: text/plain, Size: 1791 bytes --]

Provide a method to set a percpu counter to a specified value.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
 include/linux/percpu_counter.h |    6 ++++++
 lib/percpu_counter.c           |   14 ++++++++++++++
 2 files changed, 20 insertions(+)

Index: linux-2.6/include/linux/percpu_counter.h
===================================================================

--- linux-2.6.orig/include/linux/percpu_counter.h
+++ linux-2.6/include/linux/percpu_counter.h
@@ -32,6 +32,7 @@ struct percpu_counter {
 
 void percpu_counter_init(struct percpu_counter *fbc, s64 amount);
 void percpu_counter_destroy(struct percpu_counter *fbc);
+void percpu_counter_set(struct percpu_counter *fbc, s64 amount);
 void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch);
 s64 percpu_counter_sum(struct percpu_counter *fbc);
 
@@ -75,6 +76,11 @@ static inline void percpu_counter_destro
 {
 }
 
+static inline void percpu_counter_set(struct percpu_counter *fbc, s64 amount)
+{
+	fbc->count = amount;
+}
+
 #define __percpu_counter_add(fbc, amount, batch) \
 	percpu_counter_add(fbc, amount)
 
Index: linux-2.6/lib/percpu_counter.c
===================================================================
--- linux-2.6.orig/lib/percpu_counter.c
+++ linux-2.6/lib/percpu_counter.c
@@ -14,6 +14,20 @@ static LIST_HEAD(percpu_counters);
 static DEFINE_MUTEX(percpu_counters_lock);
 #endif
 
+void percpu_counter_set(struct percpu_counter *fbc, s64 amount)
+{
+	int cpu;
+
+	spin_lock(&fbc->lock);
+	for_each_possible_cpu(cpu) {
+		s32 *pcount = per_cpu_ptr(fbc->counters, cpu);
+		*pcount = 0;
+	}
+	fbc->count = amount;
+	spin_unlock(&fbc->lock);
+}
+EXPORT_SYMBOL(percpu_counter_set);
+
 void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch)
 {
 	s64 count;

--

