[PATCH 05/17] lib: percpu_count_sum_signed()

From: Peter Zijlstra
Date: Thu Jun 14 2007 - 18:09:32 EST


Provide an accurate version of percpu_counter_read.

Should we go and replace the current use of percpu_counter_sum()
with percpu_counter_sum_positive(), and call this new primitive
percpu_counter_sum() instead?

Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
---
include/linux/percpu_counter.h | 18 +++++++++++++++++-
lib/percpu_counter.c | 6 +++---
2 files changed, 20 insertions(+), 4 deletions(-)

Index: linux-2.6/include/linux/percpu_counter.h
===================================================================
--- linux-2.6.orig/include/linux/percpu_counter.h 2007-05-23 20:37:54.000000000 +0200
+++ linux-2.6/include/linux/percpu_counter.h 2007-05-23 20:38:09.000000000 +0200
@@ -35,7 +35,18 @@ void percpu_counter_destroy(struct percp
void percpu_counter_set(struct percpu_counter *fbc, s64 amount);
void __percpu_counter_mod(struct percpu_counter *fbc, s32 amount, s32 batch);
void __percpu_counter_mod64(struct percpu_counter *fbc, s64 amount, s32 batch);
-s64 percpu_counter_sum(struct percpu_counter *fbc);
+s64 __percpu_counter_sum(struct percpu_counter *fbc);
+
+static inline s64 percpu_counter_sum(struct percpu_counter *fbc)
+{
+ s64 ret = __percpu_counter_sum(fbc);
+ return ret < 0 ? 0 : ret;
+}
+
+static inline s64 percpu_counter_sum_signed(struct percpu_counter *fbc)
+{
+ return __percpu_counter_sum(fbc);
+}

static inline void percpu_counter_mod(struct percpu_counter *fbc, s32 amount)
{
@@ -124,6 +135,11 @@ static inline s64 percpu_counter_sum(str
return percpu_counter_read_positive(fbc);
}

+static inline s64 percpu_counter_sum_signed(struct percpu_counter *fbc)
+{
+ return fbc->count;
+}
+
#endif /* CONFIG_SMP */

static inline void percpu_counter_inc(struct percpu_counter *fbc)
Index: linux-2.6/lib/percpu_counter.c
===================================================================
--- linux-2.6.orig/lib/percpu_counter.c 2007-05-23 20:38:03.000000000 +0200
+++ linux-2.6/lib/percpu_counter.c 2007-05-23 20:38:18.000000000 +0200
@@ -71,7 +71,7 @@ EXPORT_SYMBOL(__percpu_counter_mod64);
* Add up all the per-cpu counts, return the result. This is a more accurate
* but much slower version of percpu_counter_read_positive()
*/
-s64 percpu_counter_sum(struct percpu_counter *fbc)
+s64 __percpu_counter_sum(struct percpu_counter *fbc)
{
s64 ret;
int cpu;
@@ -83,9 +83,9 @@ s64 percpu_counter_sum(struct percpu_cou
ret += *pcount;
}
spin_unlock(&fbc->lock);
- return ret < 0 ? 0 : ret;
+ return ret;
}
-EXPORT_SYMBOL(percpu_counter_sum);
+EXPORT_SYMBOL(__percpu_counter_sum);

void percpu_counter_init(struct percpu_counter *fbc, s64 amount)
{

--

-
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