From: Patrick Caulfield <pcaulfie@redhat.com>
Subject: Re: [RHEL5.1 PATCH] bz#250464: Make dlm_sendd cond_resched more
Date: Fri, 14 Sep 2007 14:00:37 +0100
Bugzilla: 250464
Message-Id: <46EA85F5.1090105@redhat.com>
Changelog: [dlm] Make dlm_sendd cond_resched more


Under high recovery loads dlm_sendd can monopolise the CPU and cause soft lockups.

This one extra and one moved cond_resched() make it able to yield a little more
during such times keeping work moving.

Signed-Off-By: Patrick Caulfield <pcaulfie@redhat.com>

Patrick



diff -up linux-2.6.18.ia64/fs/dlm/lowcomms.c linux-2.6.18.ia64/fs/dlm/lowcomms.c
--- linux-2.6.18.ia64/fs/dlm/lowcomms.c	2007-09-13 03:03:44.000000000 -0500
+++ linux-2.6.18.ia64/fs/dlm/lowcomms.c	2007-09-13 09:44:40.000000000 -0500
@@ -1263,14 +1263,15 @@ static void send_to_sock(struct connecti
 		if (len) {
 			ret = sendpage(con->sock, e->page, offset, len,
 				       msg_flags);
-			if (ret == -EAGAIN || ret == 0)
+			if (ret == -EAGAIN || ret == 0) {
+				cond_resched();
 				goto out;
+			}
 			if (ret <= 0)
 				goto send_error;
-		} else {
-			/* Don't starve people filling buffers */
-			cond_resched();
 		}
+		/* Don't starve people filling buffers */
+		cond_resched();
 
 		spin_lock(&con->writequeue_lock);
 		e->offset += ret;