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authorMike Marciniszyn <mike.marciniszyn@intel.com>2015-11-02 12:13:25 -0500
committerDoug Ledford <dledford@redhat.com>2015-12-07 16:39:26 -0500
commitd144da8c6f51f48ec39d891ea9dff80169c45f3b (patch)
treeb2cc120f870989c2cb4cdd328d0cf7f8355eb012 /include
parent57ab2512138205fe7836332fb4742441e53907ff (diff)
downloadlwn-d144da8c6f51f48ec39d891ea9dff80169c45f3b.tar.gz
lwn-d144da8c6f51f48ec39d891ea9dff80169c45f3b.zip
IB/core: use RCU for uverbs id lookup
The current implementation gets a spin_lock, and at any scale with qib and hfi1 post send, the lock contention grows exponentially with the number of QPs. idr_find() is RCU compatibile, so read doesn't need the lock. Change to use rcu_read_lock() and rcu_read_unlock() in __idr_get_uobj(). kfree_rcu() is used to insure a grace period between the idr removal and actual free. Reviewed-by: Ira Weiny <ira.weiny@intel.com> Signed-off-by: Mike Marciniszyn <mike.marciniszyn@intel.com> Reviewed-By: Jason Gunthorpe <jgunthorpe@obsidianresearch.com> Signed-off-by: Doug Ledford <dledford@redhat.com>
Diffstat (limited to 'include')
-rw-r--r--include/rdma/ib_verbs.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/rdma/ib_verbs.h b/include/rdma/ib_verbs.h
index 9a68a19532ba..120da1d7f57e 100644
--- a/include/rdma/ib_verbs.h
+++ b/include/rdma/ib_verbs.h
@@ -1271,6 +1271,7 @@ struct ib_uobject {
int id; /* index into kernel idr */
struct kref ref;
struct rw_semaphore mutex; /* protects .live */
+ struct rcu_head rcu; /* kfree_rcu() overhead */
int live;
};