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authorSebastian Sanchez <sebastian.sanchez@intel.com>2018-05-02 06:43:39 -0700
committerDoug Ledford <dledford@redhat.com>2018-05-09 15:53:30 -0400
commitaf8aab71370a692eaf7e7969ba5b1a455ac20113 (patch)
tree5ea7da221cc96d1f819c87870589fca3a5d21f83 /include/rdma
parentc872a1f9e3aaf51b091ff19ef6cb1e1a298f3c90 (diff)
downloadlinux-af8aab71370a692eaf7e7969ba5b1a455ac20113.tar.bz2
IB/hfi1: Optimize kthread pointer locking when queuing CQ entries
All threads queuing CQ entries on different CQs are unnecessarily synchronized by a spin lock to check if the CQ kthread worker hasn't been destroyed before queuing an CQ entry. The lock used in 6efaf10f163d ("IB/rdmavt: Avoid queuing work into a destroyed cq kthread worker") is a device global lock and will have poor performance at scale as completions are entered from a large number of CPUs. Convert to use RCU where the read side of RCU is rvt_cq_enter() to determine that the worker is alive prior to triggering the completion event. Apply write side RCU semantics in rvt_driver_cq_init() and rvt_cq_exit(). Fixes: 6efaf10f163d ("IB/rdmavt: Avoid queuing work into a destroyed cq kthread worker") Cc: <stable@vger.kernel.org> # 4.14.x Reviewed-by: Mike Marciniszyn <mike.marciniszyn@intel.com> Signed-off-by: Sebastian Sanchez <sebastian.sanchez@intel.com> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
Diffstat (limited to 'include/rdma')
-rw-r--r--include/rdma/rdma_vt.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/include/rdma/rdma_vt.h b/include/rdma/rdma_vt.h
index 3f4c187e435d..eec495e68823 100644
--- a/include/rdma/rdma_vt.h
+++ b/include/rdma/rdma_vt.h
@@ -402,7 +402,7 @@ struct rvt_dev_info {
spinlock_t pending_lock; /* protect pending mmap list */
/* CQ */
- struct kthread_worker *worker; /* per device cq worker */
+ struct kthread_worker __rcu *worker; /* per device cq worker */
u32 n_cqs_allocated; /* number of CQs allocated for device */
spinlock_t n_cqs_lock; /* protect count of in use cqs */