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percpu counter: clean up percpu_counter_sum_and_set()

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percpu_counter_sum_and_set() and percpu_counter_sum() is the same except
the former updates the global counter after accounting.  Since we are
taking the fbc->lock to calculate the precise value of the counter in
percpu_counter_sum() anyway, it should simply set fbc->count too, as the
percpu_counter_sum_and_set() does.

This patch merges these two interfaces into one.
 
Signed-off-by: Mingming Cao <cmm@us.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Mingming Cao 2008-10-09 12:50:59 -04:00 committed by Theodore Ts'o
parent 3fa8749e58
commit 1f7c14c62c
3 changed files with 7 additions and 15 deletions
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2
fs/ext4/balloc.c
View File

@ -1624,7 +1624,7 @@ ext4_fsblk_t ext4_has_free_blocks(struct ext4_sb_info *sbi,
#ifdef CONFIG_SMP
if (free_blocks - root_blocks < FBC_BATCH)
free_blocks =
percpu_counter_sum_and_set(&sbi->s_freeblocks_counter);
percpu_counter_sum(&sbi->s_freeblocks_counter);
#endif
if (free_blocks <= root_blocks)
/* we don't have free space */

12
include/linux/percpu_counter.h
View File

@ -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, int set);
s64 __percpu_counter_sum(struct percpu_counter *fbc);
static inline void percpu_counter_add(struct percpu_counter *fbc, s64 amount)
{
@ -44,19 +44,13 @@ 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, 0);
s64 ret = __percpu_counter_sum(fbc);
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, 0);
return __percpu_counter_sum(fbc);
}
static inline s64 percpu_counter_read(struct percpu_counter *fbc)

8
lib/percpu_counter.c
View File

@ -52,7 +52,7 @@ EXPORT_SYMBOL(__percpu_counter_add);
* 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, int set)
s64 __percpu_counter_sum(struct percpu_counter *fbc)
{
s64 ret;
int cpu;
@ -62,11 +62,9 @@ s64 __percpu_counter_sum(struct percpu_counter *fbc, int set)
for_each_online_cpu(cpu) {
s32 *pcount = per_cpu_ptr(fbc->counters, cpu);
ret += *pcount;
if (set)
*pcount = 0;
*pcount = 0;
}
if (set)
fbc->count = ret;
fbc->count = ret;
spin_unlock(&fbc->lock);
return ret;