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authorRoland Dreier <rolandd@cisco.com>2006-06-17 23:44:49 -0400
committerRoland Dreier <rolandd@cisco.com>2006-06-17 23:44:49 -0400
commit9ead190bfde2a434c74ea604382d08acb2eceef5 (patch)
tree937f1bb8dedea56efc46aed12370bb3865898763 /include/rdma
parentc93b6fbaa99bb3a1552e14317296be14dde51dfb (diff)
IB/uverbs: Don't serialize with ib_uverbs_idr_mutex
Currently, all userspace verbs operations that call into the kernel are serialized by ib_uverbs_idr_mutex. This can be a scalability issue for some workloads, especially for devices driven by the ipath driver, which needs to call into the kernel even for datapath operations. Fix this by adding reference counts to the userspace objects, and then converting ib_uverbs_idr_mutex into a spinlock that only protects the idrs long enough to take a reference on the object being looked up. Because remove operations may fail, we have to do a slightly funky two-step deletion, which is described in the comments at the top of uverbs_cmd.c. This also still leaves ib_uverbs_idr_lock as a single lock that is possibly subject to contention. However, the lock hold time will only be a single idr operation, so multiple threads should still be able to make progress, even if ib_uverbs_idr_lock is being ping-ponged. Surprisingly, these changes even shrink the object code: add/remove: 23/5 grow/shrink: 4/21 up/down: 633/-693 (-60) Signed-off-by: Roland Dreier <rolandd@cisco.com>
Diffstat (limited to 'include/rdma')
-rw-r--r--include/rdma/ib_verbs.h4
1 files changed, 4 insertions, 0 deletions
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 7ced208edacf..ee1f3a355666 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -697,8 +697,12 @@ struct ib_ucontext {
697struct ib_uobject { 697struct ib_uobject {
698 u64 user_handle; /* handle given to us by userspace */ 698 u64 user_handle; /* handle given to us by userspace */
699 struct ib_ucontext *context; /* associated user context */ 699 struct ib_ucontext *context; /* associated user context */
700 void *object; /* containing object */
700 struct list_head list; /* link to context's list */ 701 struct list_head list; /* link to context's list */
701 u32 id; /* index into kernel idr */ 702 u32 id; /* index into kernel idr */
703 struct kref ref;
704 struct rw_semaphore mutex; /* protects .live */
705 int live;
702}; 706};
703 707
704struct ib_umem { 708struct ib_umem {