[v1,10/22] SUNRPC: Mitigate cond_resched() in xprt_transmit()
diff mbox series

Message ID 20200708200953.22129.63543.stgit@manet.1015granger.net
State New
Headers show
Series
  • SUNRPC: Replace dprintk calls with tracepoints
Related show

Commit Message

Chuck Lever July 8, 2020, 8:09 p.m. UTC
The original purpose of this expensive call is to prevent a long
queue of requests from blocking other work.

The cond_resched() call is unnecessary after just a single send
operation.

For longer queues, instead of invoking the kernel scheduler, simply
release the transport send lock and return to the RPC scheduler.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 net/sunrpc/xprt.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

Patch
diff mbox series

diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index a03f67520780..52aac652bab9 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -1504,10 +1504,13 @@  xprt_transmit(struct rpc_task *task)
 {
 	struct rpc_rqst *next, *req = task->tk_rqstp;
 	struct rpc_xprt	*xprt = req->rq_xprt;
-	int status;
+	int counter, status;
 
 	spin_lock(&xprt->queue_lock);
+	counter = 0;
 	while (!list_empty(&xprt->xmit_queue)) {
+		if (++counter == 20)
+			break;
 		next = list_first_entry(&xprt->xmit_queue,
 				struct rpc_rqst, rq_xmit);
 		xprt_pin_rqst(next);
@@ -1515,7 +1518,6 @@  xprt_transmit(struct rpc_task *task)
 		status = xprt_request_transmit(next, task);
 		if (status == -EBADMSG && next != req)
 			status = 0;
-		cond_resched();
 		spin_lock(&xprt->queue_lock);
 		xprt_unpin_rqst(next);
 		if (status == 0) {