From: Arjan van de Ven <arjanv@redhat.com>
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).
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/arch/i386/mm/mmap.c | 2 +-
25-akpm/include/linux/mm.h | 2 ++
25-akpm/include/linux/sysctl.h | 1 +
25-akpm/kernel/sysctl.c | 12 ++++++++++++
4 files changed, 16 insertions(+), 1 deletion(-)
diff -puN arch/i386/mm/mmap.c~sysctl-tunable-for-flexmmap arch/i386/mm/mmap.c
--- 25/arch/i386/mm/mmap.c~sysctl-tunable-for-flexmmap 2004-08-01 17:33:34.674954912 -0700
+++ 25-akpm/arch/i386/mm/mmap.c 2004-08-01 17:42:34.929823688 -0700
@@ -57,7 +57,7 @@ void arch_pick_mmap_layout(struct mm_str
* Fall back to the standard layout if the personality
* bit is set, or if the expected stack growth is unlimited:
*/
- if ((current->personality & ADDR_COMPAT_LAYOUT) ||
+ if (sysctl_legacy_va_layout || (current->personality & ADDR_COMPAT_LAYOUT) ||
current->rlim[RLIMIT_STACK].rlim_cur == RLIM_INFINITY) {
mm->mmap_base = TASK_UNMAPPED_BASE;
mm->get_unmapped_area = arch_get_unmapped_area;
diff -puN include/linux/mm.h~sysctl-tunable-for-flexmmap include/linux/mm.h
--- 25/include/linux/mm.h~sysctl-tunable-for-flexmmap 2004-08-01 17:33:34.676954608 -0700
+++ 25-akpm/include/linux/mm.h 2004-08-01 17:33:34.683953544 -0700
@@ -26,6 +26,8 @@ extern void * high_memory;
extern unsigned long vmalloc_earlyreserve;
extern int page_cluster;
+extern int sysctl_legacy_va_layout;
+
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/processor.h>
diff -puN include/linux/sysctl.h~sysctl-tunable-for-flexmmap include/linux/sysctl.h
--- 25/include/linux/sysctl.h~sysctl-tunable-for-flexmmap 2004-08-01 17:33:34.677954456 -0700
+++ 25-akpm/include/linux/sysctl.h 2004-08-01 17:33:34.684953392 -0700
@@ -166,6 +166,7 @@ enum
VM_BLOCK_DUMP=24, /* block dump mode */
VM_HUGETLB_GROUP=25, /* permitted hugetlb group */
VM_VFS_CACHE_PRESSURE=26, /* dcache/icache reclaim pressure */
+ VM_LEGACY_VA_LAYOUT=27, /* legacy/compatibility virtual address space layout */
};
diff -puN kernel/sysctl.c~sysctl-tunable-for-flexmmap kernel/sysctl.c
--- 25/kernel/sysctl.c~sysctl-tunable-for-flexmmap 2004-08-01 17:33:34.679954152 -0700
+++ 25-akpm/kernel/sysctl.c 2004-08-01 17:42:34.928823840 -0700
@@ -149,6 +149,8 @@ extern ctl_table random_table[];
extern ctl_table pty_table[];
#endif
+int sysctl_legacy_va_layout;
+
/* /proc declarations: */
#ifdef CONFIG_PROC_FS
@@ -805,6 +807,16 @@ static ctl_table vm_table[] = {
.strategy = &sysctl_intvec,
.extra1 = &zero,
},
+ {
+ .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,
+ },
{ .ctl_name = 0 }
};
_