dlm: reduce cond_resched during send

Calling cond_resched() after every send can unnecessarily
degrade performance.  Go back to an old method of scheduling
after 25 messages.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: David Teigland <teigland@redhat.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/fs/dlm/lowcomms.c b/fs/dlm/lowcomms.c
index 2bedb0ac5f92..0e75f152eac2 100644
--- a/fs/dlm/lowcomms.c
+++ b/fs/dlm/lowcomms.c
@@ -63,6 +63,9 @@
 #define NEEDED_RMEM (4*1024*1024)
 #define CONN_HASH_SIZE 32
 
+/* Number of messages to send before rescheduling */
+#define MAX_SEND_MSG_COUNT 25
+
 struct cbuf {
         unsigned int base;
         unsigned int len;
@@ -1318,6 +1321,7 @@ static void send_to_sock(struct connection *con)
         const int msg_flags = MSG_DONTWAIT | MSG_NOSIGNAL;
         struct writequeue_entry *e;
         int len, offset;
+        int count = 0;
 
         mutex_lock(&con->sock_mutex);
         if (con->sock == NULL)
@@ -1355,8 +1359,12 @@ static void send_to_sock(struct connection *con)
                         if (ret <= 0)
                                 goto send_error;
                 }
-                        /* Don't starve people filling buffers */
+
+                /* Don't starve people filling buffers */
+                if (++count >= MAX_SEND_MSG_COUNT) {
                         cond_resched();
+                        count = 0;
+                }
 
                 spin_lock(&con->writequeue_lock);
                 e->offset += ret;