From 64e3b6b67906efd7dcd2e50e8dc561cef86e5ce0 Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjanv@redhat.com>
Date: Mon, 23 Aug 2004 21:12:13 -0700
Subject: [PATCH] sysctl tunable for flexmmap

  Create /proc/sys/vm/legacy_va_layout.  If this is non-zero, the kernel
  will use the old mmap layout for all tasks.  it presently defaults to zero
  (the new layout).

From: William Lee Irwin III <wli@holomorphy.com>

  hugetlb CONFIG_SYSCTL=n fix

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
 kernel/sysctl.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

(limited to 'kernel')

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 2c5c58279f81..4a361348038e 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -42,6 +42,7 @@
 #include <linux/dcache.h>
 
 #include <asm/uaccess.h>
+#include <asm/processor.h>
 
 #ifdef CONFIG_ROOT_NFS
 #include <linux/nfs_fs.h>
@@ -149,6 +150,10 @@ extern ctl_table random_table[];
 extern ctl_table pty_table[];
 #endif
 
+#ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
+int sysctl_legacy_va_layout;
+#endif
+
 /* /proc declarations: */
 
 #ifdef CONFIG_PROC_FS
@@ -805,6 +810,18 @@ static ctl_table vm_table[] = {
 		.strategy	= &sysctl_intvec,
 		.extra1		= &zero,
 	},
+#ifdef HAVE_ARCH_PICK_MMAP_LAYOUT
+	{
+		.ctl_name	= VM_LEGACY_VA_LAYOUT,
+		.procname	= "legacy_va_layout",
+		.data		= &sysctl_legacy_va_layout,
+		.maxlen		= sizeof(sysctl_legacy_va_layout),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec,
+		.strategy	= &sysctl_intvec,
+		.extra1		= &zero,
+	},
+#endif
 	{ .ctl_name = 0 }
 };
 
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