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| author | Sebastian Sanchez <sebastian.sanchez@intel.com> | 2018-05-02 16:43:39 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-07-03 12:24:54 +0300 |
| commit | 964705c4a69183182362977c28786e789a384700 (patch) | |
| tree | 1938caa76732c5b07665b16db30155574e5cdc06 /include/rdma | |
| parent | 2bd28cba43bd24ad3c8b485c3ab4bb4a65564b0c (diff) | |
| download | linux-964705c4a69183182362977c28786e789a384700.tar.xz | |
IB/hfi1: Optimize kthread pointer locking when queuing CQ entries
commit af8aab71370a692eaf7e7969ba5b1a455ac20113 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'include/rdma')
| -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 1ba84a78f1c5..c653af91da16 100644 --- a/include/rdma/rdma_vt.h +++ b/include/rdma/rdma_vt.h @@ -409,7 +409,7 @@ 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 */ |