[src/yamt-pagecache]: src/sys/uvm turn vm.loanread sysctl to a threshold.

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

details:   https://anonhg.NetBSD.org/src/rev/a2d98e34a3d6
branches:  yamt-pagecache
changeset: 770869:a2d98e34a3d6
user:      yamt <yamt%NetBSD.org@localhost>
date:      Sun Feb 05 04:58:29 2012 +0000

description:
turn vm.loanread sysctl to a threshold.

diffstat:

 sys/uvm/uvm_extern.h |   4 ++--
 sys/uvm/uvm_loan.c   |   8 ++++----
 sys/uvm/uvm_meter.c  |  11 ++++++-----
 3 files changed, 12 insertions(+), 11 deletions(-)

diffs (86 lines):

diff -r 2eff7fa2c546 -r a2d98e34a3d6 sys/uvm/uvm_extern.h
--- a/sys/uvm/uvm_extern.h      Wed Jan 25 00:41:36 2012 +0000
+++ b/sys/uvm/uvm_extern.h      Sun Feb 05 04:58:29 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_extern.h,v 1.176.2.7 2012/01/11 00:08:40 yamt Exp $        */
+/*     $NetBSD: uvm_extern.h,v 1.176.2.8 2012/02/05 04:58:29 yamt Exp $        */
 
 /*
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -505,7 +505,7 @@
 /* MD code needs this without including <uvm/uvm.h> */
 extern bool vm_page_zero_enable;
 
-extern bool vm_loan_read;
+extern int vm_loan_read_thresh;
 #endif
 
 /*
diff -r 2eff7fa2c546 -r a2d98e34a3d6 sys/uvm/uvm_loan.c
--- a/sys/uvm/uvm_loan.c        Wed Jan 25 00:41:36 2012 +0000
+++ b/sys/uvm/uvm_loan.c        Sun Feb 05 04:58:29 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_loan.c,v 1.81.2.13 2012/01/25 00:41:36 yamt Exp $  */
+/*     $NetBSD: uvm_loan.c,v 1.81.2.14 2012/02/05 04:58:29 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 1.81.2.13 2012/01/25 00:41:36 yamt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_loan.c,v 1.81.2.14 2012/02/05 04:58:29 yamt Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -42,7 +42,7 @@
 
 #include <uvm/uvm.h>
 
-bool vm_loan_read = true;
+int vm_loan_read_thresh = MAXPHYS;
 
 /*
  * "loaned" pages are pages which are (read-only, copy-on-write) loaned
@@ -1304,7 +1304,7 @@
        size_t len;
        int i, error = 0;
 
-       if (!vm_loan_read) {
+       if (vm_loan_read_thresh > 0 && uio->uio_resid < vm_loan_read_thresh) {
                return ENOSYS;
        }
 
diff -r 2eff7fa2c546 -r a2d98e34a3d6 sys/uvm/uvm_meter.c
--- a/sys/uvm/uvm_meter.c       Wed Jan 25 00:41:36 2012 +0000
+++ b/sys/uvm/uvm_meter.c       Sun Feb 05 04:58:29 2012 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: uvm_meter.c,v 1.56.4.7 2012/01/11 00:08:41 yamt Exp $  */
+/*     $NetBSD: uvm_meter.c,v 1.56.4.8 2012/02/05 04:58:29 yamt Exp $  */
 
 /*
  * Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -36,7 +36,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_meter.c,v 1.56.4.7 2012/01/11 00:08:41 yamt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_meter.c,v 1.56.4.8 2012/02/05 04:58:29 yamt Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -324,9 +324,10 @@
                       CTL_VM, CTL_CREATE, CTL_EOL);
        sysctl_createv(clog, 0, NULL, NULL,
                       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
-                      CTLTYPE_BOOL, "loanread",
-                      SYSCTL_DESCR("Use page loaning for read"),
-                      NULL, 0, &vm_loan_read, 0,
+                      CTLTYPE_INT, "loan_read_thresh",
+                      SYSCTL_DESCR(
+                          "Threshold in bytes to use page loaning for read"),
+                      NULL, 0, &vm_loan_read_thresh, 0,
                       CTL_VM, CTL_CREATE, CTL_EOL);
 
        uvmpdpol_sysctlsetup();