In new barrier codes, raise_barrier waits if conf->nr_pending[idx] is not zero.
After all the conditions are true, the resync request can go on be handled. But
it adds conf->nr_pending[idx] again. The next resync request hit the same bucket
idx need to wait the resync request which is submitted before. The performance
of resync/recovery is degraded.
So we should use a new variable to count sync requests which are in flight.
Suggested-by: Shaohua Li <shli@xxxxxxxxxx>
Suggested-by: Coly Li <colyli@xxxxxxx>
Signed-off-by: Xiao Ni <xni@xxxxxxxxxx>
---
drivers/md/raid1.c | 14 +++++++++++---
drivers/md/raid1.h | 1 +
2 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/drivers/md/raid1.c b/drivers/md/raid1.c
index a34f587..3c304ef 100644
--- a/drivers/md/raid1.c
+++ b/drivers/md/raid1.c
@@ -869,7 +869,7 @@ static void raise_barrier(struct r1conf *conf, sector_t sector_nr)
atomic_read(&conf->barrier[idx]) < RESYNC_DEPTH,
conf->resync_lock);
- atomic_inc(&conf->nr_pending[idx]);
+ atomic_inc(&conf->nr_sync_pending[idx]);
spin_unlock_irq(&conf->resync_lock);
}
@@ -880,7 +880,7 @@ static void lower_barrier(struct r1conf *conf, sector_t sector_nr)
BUG_ON(atomic_read(&conf->barrier[idx]) <= 0);
atomic_dec(&conf->barrier[idx]);
- atomic_dec(&conf->nr_pending[idx]);
+ atomic_dec(&conf->nr_sync_pending[idx]);
wake_up(&conf->wait_barrier);
}
@@ -1018,7 +1018,8 @@ static int get_unqueued_pending(struct r1conf *conf)
int idx, ret;
for (ret = 0, idx = 0; idx < BARRIER_BUCKETS_NR; idx++)
- ret += atomic_read(&conf->nr_pending[idx]) -
+ ret += atomic_read(&conf->nr_pending[idx]) +
+ atomic_read(&conf->nr_sync_pending[idx]) -
atomic_read(&conf->nr_queued[idx]);
return ret;
@@ -3024,6 +3025,11 @@ static struct r1conf *setup_conf(struct mddev *mddev)
if (!conf->nr_pending)
goto abort;
+ conf->nr_sync_pending = kcalloc(BARRIER_BUCKETS_NR,
+ sizeof(atomic_t), GFP_KERNEL);
+ if (!conf->nr_sync_pending)
+ goto abort;
+
conf->nr_waiting = kcalloc(BARRIER_BUCKETS_NR,
sizeof(atomic_t), GFP_KERNEL);
if (!conf->nr_waiting)
@@ -3136,6 +3142,7 @@ static struct r1conf *setup_conf(struct mddev *mddev)
kfree(conf->mirrors);
safe_put_page(conf->tmppage);
kfree(conf->poolinfo);
+ kfree(conf->nr_sync_pending);
kfree(conf->nr_pending);
kfree(conf->nr_waiting);
kfree(conf->nr_queued);
@@ -3241,6 +3248,7 @@ static void raid1_free(struct mddev *mddev, void *priv)
kfree(conf->mirrors);
safe_put_page(conf->tmppage);
kfree(conf->poolinfo);
+ kfree(conf->nr_sync_pending);
kfree(conf->nr_pending);
kfree(conf->nr_waiting);
kfree(conf->nr_queued);
diff --git a/drivers/md/raid1.h b/drivers/md/raid1.h
index dd22a37..a3580ee 100644
--- a/drivers/md/raid1.h
+++ b/drivers/md/raid1.h
@@ -85,6 +85,7 @@ struct r1conf {
wait_queue_head_t wait_barrier;
spinlock_t resync_lock;
atomic_t *nr_pending;
+ atomic_t *nr_sync_pending;
atomic_t *nr_waiting;
atomic_t *nr_queued;
atomic_t *barrier;
--
2.7.4
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