[PATCH 27/27] staging: lustre: do less intense allocating retry for ko2iblnd

James Simmons
2016-03-02T22:03:05Z

From: Liang Zhen <liang.zhen@intel.com>

ko2iblnd may retry too frequent for growing pools, all schedulers
are spinning if another thread is in progress of allocating a new
pool and can't finish right away because of high system load.

Signed-off-by: Liang Zhen <liang.zhen@intel.com>
Intel-bug-id: https://jira.hpdd.intel.com/browse/LU-7054
Reviewed-on: http://review.whamcloud.com/16470
Reviewed-by: Doug Oucharek <doug.s.oucharek@intel.com>
Reviewed-by: James Simmons <uja.ornl@yahoo.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>
---
.../staging/lustre/lnet/klnds/o2iblnd/o2iblnd.c | 20 ++++++++++++++++----
1 files changed, 16 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.c b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.c
index 135ccf1..0d32e65 100644
--- a/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.c
+++ b/drivers/staging/lustre/lnet/klnds/o2iblnd/o2iblnd.c
@@ -1218,6 +1218,7 @@ static kib_hca_dev_t *kiblnd_current_hdev(kib_dev_t *dev)
if (!(i++ % 50))
CDEBUG(D_NET, "%s: Wait for failover\n",
dev->ibd_ifname);
+ set_current_state(TASK_INTERRUPTIBLE);
schedule_timeout(cfs_time_seconds(1) / 100);

read_lock_irqsave(&kiblnd_data.kib_global_lock, flags);
@@ -1684,6 +1685,9 @@ struct list_head *kiblnd_pool_alloc_node(kib_poolset_t *ps)
{
struct list_head *node;
kib_pool_t *pool;
+ unsigned int interval = 1;
+ unsigned long time_before;
+ unsigned int trips = 0;
int rc;

again:
@@ -1709,9 +1713,15 @@ struct list_head *kiblnd_pool_alloc_node(kib_poolset_t *ps)
if (ps->ps_increasing) {
/* another thread is allocating a new pool */
spin_unlock(&ps->ps_lock);
- CDEBUG(D_NET, "Another thread is allocating new %s pool, waiting for her to complete\n",
- ps->ps_name);
- schedule();
+ trips++;
+ CDEBUG(D_NET, "Another thread is allocating new %s pool, waiting %d HZs for her to complete. trips = %d\n",
+ ps->ps_name, interval, trips);
+
+ set_current_state(TASK_INTERRUPTIBLE);
+ schedule_timeout(interval);
+ if (interval < cfs_time_seconds(1))
+ interval *= 2;
+
goto again;
}

@@ -1725,8 +1735,10 @@ struct list_head *kiblnd_pool_alloc_node(kib_poolset_t *ps)
spin_unlock(&ps->ps_lock);

CDEBUG(D_NET, "%s pool exhausted, allocate new pool\n", ps->ps_name);
-
+ time_before = cfs_time_current();
rc = ps->ps_pool_create(ps, ps->ps_pool_size, &pool);
+ CDEBUG(D_NET, "ps_pool_create took %lu HZ to complete",
+ cfs_time_current() - time_before);

spin_lock(&ps->ps_lock);
ps->ps_increasing = 0;
--
1.7.1