In function eventual(), if the value of stopflag become larger than zero (the
''if'' branch is taken), then only the "eventual( )" thread updates stopflag.
So, the READ_ONCE() within the WRITE_ONCE() is not necessary. Remove it.
In function count_cleanup(), there is no need to run smp_mb( ) in between
statement writing to and statement reading from the same variable, stopflag.
Remove smp_mb().
Suggested-by: Akira Yokosawa <akiyks@xxxxxxxxx>
Signed-off-by: Junchang Wang <junchangwang@xxxxxxxxx>
---
CodeSamples/count/count_stat_eventual.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/CodeSamples/count/count_stat_eventual.c b/CodeSamples/count/count_stat_eventual.c
index 464de30..1365168 100644
--- a/CodeSamples/count/count_stat_eventual.c
+++ b/CodeSamples/count/count_stat_eventual.c
@@ -40,16 +40,17 @@ void *eventual(void *arg)
{
int t;
unsigned long sum;
+ int stopflag_l = 0;
- while (READ_ONCE(stopflag) < 3) {
+ while (stopflag_l < 3) {
sum = 0;
for_each_thread(t)
sum += READ_ONCE(per_thread(counter, t));
WRITE_ONCE(global_count, sum);
poll(NULL, 0, 1);
- if (READ_ONCE(stopflag)) {
+ if ((stopflag_l = READ_ONCE(stopflag)) != 0) {
smp_mb();
- WRITE_ONCE(stopflag, READ_ONCE(stopflag) + 1);
+ WRITE_ONCE(stopflag, ++stopflag_l);
}
}
return NULL;
@@ -68,7 +69,6 @@ void count_init(void)
void count_cleanup(void)
{
WRITE_ONCE(stopflag, 1);
- smp_mb();
while (READ_ONCE(stopflag) < 3)
poll(NULL, 0, 1);
smp_mb();
--
2.7.4
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