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authorMingming Cao <cmm@us.ibm.com>2008-07-12 03:27:31 +0400
committerTheodore Ts'o <tytso@mit.edu>2008-07-12 03:27:31 +0400
commite8ced39d5e8911c662d4d69a342b9d053eaaac4e (patch)
treecd4d643bfbd37c67ff9bd2feff2c0b477a56f117 /include/linux/percpu_counter.h
parent64769240bd07f446f83660bb143bb609d8ab4910 (diff)
downloadlinux-e8ced39d5e8911c662d4d69a342b9d053eaaac4e.tar.xz
percpu_counter: new function percpu_counter_sum_and_set
Delayed allocation need to check free blocks at every write time. percpu_counter_read_positive() is not quit accurate. delayed allocation need a more accurate accounting, but using percpu_counter_sum_positive() is frequently is quite expensive. This patch added a new function to update center counter when sum per-cpu counter, to increase the accurate rate for next percpu_counter_read() and require less calling expensive percpu_counter_sum(). Signed-off-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'include/linux/percpu_counter.h')
-rw-r--r--include/linux/percpu_counter.h12
1 files changed, 9 insertions, 3 deletions
diff --git a/include/linux/percpu_counter.h b/include/linux/percpu_counter.h
index 9007ccdfc112..208388835357 100644
--- a/include/linux/percpu_counter.h
+++ b/include/linux/percpu_counter.h
@@ -35,7 +35,7 @@ int percpu_counter_init_irq(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);
+s64 __percpu_counter_sum(struct percpu_counter *fbc, int set);
static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount)
{
@@ -44,13 +44,19 @@ static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount)
static inline s64 percpu_counter_sum_positive(struct percpu_counter *fbc)
{
- s64 ret = __percpu_counter_sum(fbc);
+ s64 ret = __percpu_counter_sum(fbc, 0);
return ret < 0 ? 0 : ret;
}
+static inline s64 percpu_counter_sum_and_set(struct percpu_counter *fbc)
+{
+ return __percpu_counter_sum(fbc, 1);
+}
+
+
static inline s64 percpu_counter_sum(struct percpu_counter *fbc)
{
- return __percpu_counter_sum(fbc);
+ return __percpu_counter_sum(fbc, 0);
}
static inline s64 percpu_counter_read(struct percpu_counter *fbc)