svn commit: r251788 - user/attilio/vmobj-readlock/sys/kern

[Attilio Rao]

Author: attilio
Date: Sat Jun 15 10:09:20 2013
New Revision: 251788
URL: http://svnweb.freebsd.org/changeset/base/251788

Log:
  Avoid to soft busy the page before to do vn_rdwr() in kern_sendfile().
  That is unnecessary.  The page is infact already wired and concurrent
  accesses to the specified page and off should be serialized
  already by vn_rdwr().
  
  Sponsored by:	EMC / Isilon storage division
  Discussed with:	jeff, dillon

Modified:
  user/attilio/vmobj-readlock/sys/kern/uipc_syscalls.c

Modified: user/attilio/vmobj-readlock/sys/kern/uipc_syscalls.c
==============================================================================
--- user/attilio/vmobj-readlock/sys/kern/uipc_syscalls.c	Sat Jun 15 10:08:34 2013	(r251787)
+++ user/attilio/vmobj-readlock/sys/kern/uipc_syscalls.c	Sat Jun 15 10:09:20 2013	(r251788)
@@ -2219,11 +2219,6 @@ retry_space:
 			else {
 				ssize_t resid;
 
-				/*
-				 * Ensure that our page is still around
-				 * when the I/O completes.
-				 */
-				vm_page_io_start(pg);
 				VM_OBJECT_WUNLOCK(obj);
 
 				/*
@@ -2237,11 +2232,9 @@ retry_space:
 				    trunc_page(off), UIO_NOCOPY, IO_NODELOCKED |
 				    IO_VMIO | ((MAXBSIZE / bsize) << IO_SEQSHIFT),
 				    td->td_ucred, NOCRED, &resid, td);
-				VM_OBJECT_WLOCK(obj);
-				vm_page_io_finish(pg);
-				if (!error)
-					VM_OBJECT_WUNLOCK(obj);
 				mbstat.sf_iocnt++;
+				if (error)
+					VM_OBJECT_WLOCK(obj);
 			}
 			if (error) {
 				vm_page_lock(pg);