rds: per-rm flush_wait waitq

This removes a global waitqueue used to wait for rds messages
and replaces it with a waitqueue inside the rds_message struct.

The global waitqueue turns into a global lock and significantly
bottlenecks operations on large machines.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

2 files changed, 5 insertions, 4 deletions

diff --git a/net/rds/message.c b/net/rds/message.c
index 4cb1ed704153..96e2bf7dc77e 100644
--- a/net/rds/message.c
+++ b/net/rds/message.c
@@ -35,8 +35,6 @@
 
 #include "rds.h"
 
-static DECLARE_WAIT_QUEUE_HEAD(rds_message_flush_waitq);
-
 static unsigned int     rds_exthdr_size[__RDS_EXTHDR_MAX] = {
 [RDS_EXTHDR_NONE]       = 0,
 [RDS_EXTHDR_VERSION]    = sizeof(struct rds_ext_header_version),
@@ -226,6 +224,7 @@ struct rds_message *rds_message_alloc(unsigned int extra_len, gfp_t gfp)
         INIT_LIST_HEAD(&rm->m_sock_item);
         INIT_LIST_HEAD(&rm->m_conn_item);
         spin_lock_init(&rm->m_rs_lock);
+        init_waitqueue_head(&rm->m_flush_wait);
 
 out:
         return rm;
@@ -399,14 +398,14 @@ int rds_message_inc_copy_to_user(struct rds_incoming *inc,
  */
 void rds_message_wait(struct rds_message *rm)
 {
-        wait_event_interruptible(rds_message_flush_waitq,
+        wait_event_interruptible(rm->m_flush_wait,
                         !test_bit(RDS_MSG_MAPPED, &rm->m_flags));
 }
 
 void rds_message_unmapped(struct rds_message *rm)
 {
         clear_bit(RDS_MSG_MAPPED, &rm->m_flags);
-        wake_up_interruptible(&rds_message_flush_waitq);
+        wake_up_interruptible(&rm->m_flush_wait);
 }
 EXPORT_SYMBOL_GPL(rds_message_unmapped);
 
diff --git a/net/rds/rds.h b/net/rds/rds.h
index b57cb50c1f22..c22bd7b49460 100644
--- a/net/rds/rds.h
+++ b/net/rds/rds.h
@@ -301,6 +301,8 @@ struct rds_message {
          *   -> rs->rs_lock
          */
         spinlock_t              m_rs_lock;
+        wait_queue_head_t       m_flush_wait;
+
         struct rds_sock         *m_rs;
 
         /* cookie to send to remote, in rds header */