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| author |   Sebastian Sanchez <sebastian.sanchez@intel.com> | 2018-05-02 06:43:39 -0700 |
|---|---|---|
| committer |   Doug Ledford <dledford@redhat.com> | 2018-05-09 15:53:30 -0400 |
| commit | af8aab71370a692eaf7e7969ba5b1a455ac20113 (patch) | |
| tree | 5ea7da221cc96d1f819c87870589fca3a5d21f83 /include | |
| parent | IB/Hfi1: Read CCE Revision register to verify the device is responsive (diff) | |
| download | linux-dev-af8aab71370a692eaf7e7969ba5b1a455ac20113.tar.xz linux-dev-af8aab71370a692eaf7e7969ba5b1a455ac20113.zip | |
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')
| -rw-r--r-- | include/rdma/rdma_vt.h | 2 |
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 */ |