[src/yamt-pagecache]: src/sys/uvm as usefulness of O->A loaning is unclear, d...

[yamt <yamt%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/844887a183db
branches:  yamt-pagecache
changeset: 770881:844887a183db
user:      yamt <yamt%NetBSD.org@localhost>
date:      Tue Jun 12 17:12:01 2012 +0000

description:
as usefulness of O->A loaning is unclear, disable it by default for now.

requested by rmind.
http://mail-index.NetBSD.org/tech-kern/2012/05/08/msg013139.html

diffstat:

 sys/uvm/uvm_loan.c |  8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diffs (36 lines):

diff -r 5982ae213c05 -r 844887a183db sys/uvm/uvm_loan.c
--- a/sys/uvm/uvm_loan.c        Wed May 23 10:07:03 2012 +0000
+++ b/sys/uvm/uvm_loan.c        Tue Jun 12 17:12:01 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_loan.c,v 1.81.2.16 2012/04/17 00:08:59 yamt Exp $  */
+/*     $NetBSD: uvm_loan.c,v 1.81.2.17 2012/06/12 17:12:01 yamt Exp $  */
 
 /*
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -32,7 +32,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_loan.c,v 1.81.2.16 2012/04/17 00:08:59 yamt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_loan.c,v 1.81.2.17 2012/06/12 17:12:01 yamt Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -42,7 +42,7 @@
 
 #include <uvm/uvm.h>
 
-int vm_loan_read_thresh = MAXPHYS;
+int vm_loan_read_thresh = -1;
 
 /*
  * "loaned" pages are pages which are (read-only, copy-on-write) loaned
@@ -1303,7 +1303,7 @@
        size_t len;
        int i, error = 0;
 
-       if (vm_loan_read_thresh > 0 && uio->uio_resid < vm_loan_read_thresh) {
+       if (vm_loan_read_thresh < 0 || uio->uio_resid < vm_loan_read_thresh) {
                return ENOSYS;
        }