Commit 1f7c14c6 authored by Mingming Cao's avatar Mingming Cao Committed by Theodore Ts'o
Browse files

percpu counter: clean up percpu_counter_sum_and_set() 



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: default avatarMingming Cao <cmm@us.ibm.com>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 3fa8749e

fs/ext4/balloc.c

+1 −1
Original line number Diff line number Diff line
@@ -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 */

include/linux/percpu_counter.h

+3 −9
Original line number Diff line number Diff line
@@ -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)

lib/percpu_counter.c

+3 −5
Original line number Diff line number Diff line
@@ -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;
@@ -62,10 +62,8 @@ 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;

	}

	if (set)

	fbc->count = ret;



	spin_unlock(&fbc->lock);

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