[PATCH] as-iosched: use new io context counting mechanism
It's ok if the read path is a lot more costly, as long as inc/dec is
really cheap. The inc/dec will happen for each created/freed io context,
while the reading only happens when a disk queue exits.
Signed-off-by: Jens Axboe <axboe@suse.de>
diff --git a/block/as-iosched.c b/block/as-iosched.c
index 66015bc..8e1fef1 100644
--- a/block/as-iosched.c
+++ b/block/as-iosched.c
@@ -149,7 +149,7 @@
#define RQ_STATE(rq) ((enum arq_state)(rq)->elevator_private2)
#define RQ_SET_STATE(rq, state) ((rq)->elevator_private2 = (void *) state)
-static atomic_t ioc_count = ATOMIC_INIT(0);
+static DEFINE_PER_CPU(unsigned long, ioc_count);
static struct completion *ioc_gone;
static void as_move_to_dispatch(struct as_data *ad, struct request *rq);
@@ -163,7 +163,8 @@
static void free_as_io_context(struct as_io_context *aic)
{
kfree(aic);
- if (atomic_dec_and_test(&ioc_count) && ioc_gone)
+ elv_ioc_count_dec(ioc_count);
+ if (ioc_gone && !elv_ioc_count_read(ioc_count))
complete(ioc_gone);
}
@@ -199,7 +200,7 @@
ret->seek_total = 0;
ret->seek_samples = 0;
ret->seek_mean = 0;
- atomic_inc(&ioc_count);
+ elv_ioc_count_inc(ioc_count);
}
return ret;
@@ -1484,7 +1485,7 @@
ioc_gone = &all_gone;
/* ioc_gone's update must be visible before reading ioc_count */
smp_wmb();
- if (atomic_read(&ioc_count))
+ if (elv_ioc_count_read(ioc_count))
wait_for_completion(ioc_gone);
synchronize_rcu();
}