svn commit: r261064 - stable/9/sys/rpc

[Alexander Motin]

Author: mav
Date: Thu Jan 23 00:44:14 2014
New Revision: 261064
URL: http://svnweb.freebsd.org/changeset/base/261064

Log:
  MFC r260031:
  In addition to r259632 completely block receive upcalls if we have more
  data than we need.  This reduces lock pressure from xprt_active() side.

Modified:
  stable/9/sys/rpc/svc_vc.c
Directory Properties:
  stable/9/   (props changed)
  stable/9/sys/   (props changed)

Modified: stable/9/sys/rpc/svc_vc.c
==============================================================================
--- stable/9/sys/rpc/svc_vc.c	Thu Jan 23 00:43:33 2014	(r261063)
+++ stable/9/sys/rpc/svc_vc.c	Thu Jan 23 00:44:14 2014	(r261064)
@@ -619,7 +619,15 @@ svc_vc_process_pending(SVCXPRT *xprt)
 		}
 	}
 
-	so->so_rcv.sb_lowat = imax(1, imin(cd->resid, so->so_rcv.sb_hiwat / 2));
+	/*
+	 * Block receive upcalls if we have more data pending,
+	 * otherwise report our need.
+	 */
+	if (cd->mpending)
+		so->so_rcv.sb_lowat = INT_MAX;
+	else
+		so->so_rcv.sb_lowat =
+		    imax(1, imin(cd->resid, so->so_rcv.sb_hiwat / 2));
 	return (TRUE);
 }