- Add documentation.
- It's an x86-only feature, so don't offer the sysctl on other architectures.
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/Documentation/filesystems/proc.txt | 6 ++++++
25-akpm/arch/i386/mm/mmap.c | 5 ++++-
25-akpm/include/asm-i386/page.h | 4 ++--
25-akpm/kernel/sysctl.c | 4 ++--
4 files changed, 14 insertions(+), 5 deletions(-)
diff -puN Documentation/filesystems/proc.txt~legacy_va_layout-docs Documentation/filesystems/proc.txt
--- 25/Documentation/filesystems/proc.txt~legacy_va_layout-docs 2004-08-01 18:02:55.376287624 -0700
+++ 25-akpm/Documentation/filesystems/proc.txt 2004-08-01 18:02:55.386286104 -0700
@@ -1174,6 +1174,12 @@ for writeout by the pdflush daemons. It
Data which has been dirty in-memory for longer than this interval will be
written out next time a pdflush daemon wakes up.
+legacy_va_layout
+----------------
+
+If non-zero, this sysctl disables the new i386 mmap layout - the kernel will
+use the legacy (2.4) layout for all processes.
+
lower_zone_protection
---------------------
diff -puN kernel/sysctl.c~legacy_va_layout-docs kernel/sysctl.c
--- 25/kernel/sysctl.c~legacy_va_layout-docs 2004-08-01 18:02:55.378287320 -0700
+++ 25-akpm/kernel/sysctl.c 2004-08-01 21:20:27.477494368 -0700
@@ -149,8 +149,6 @@ extern ctl_table random_table[];
extern ctl_table pty_table[];
#endif
-int sysctl_legacy_va_layout;
-
/* /proc declarations: */
#ifdef CONFIG_PROC_FS
@@ -807,6 +805,7 @@ static ctl_table vm_table[] = {
.strategy = &sysctl_intvec,
.extra1 = &zero,
},
+#ifdef __i386__
{
.ctl_name = VM_LEGACY_VA_LAYOUT,
.procname = "legacy_va_layout",
@@ -817,6 +816,7 @@ static ctl_table vm_table[] = {
.strategy = &sysctl_intvec,
.extra1 = &zero,
},
+#endif
{ .ctl_name = 0 }
};
diff -puN include/asm-i386/page.h~legacy_va_layout-docs include/asm-i386/page.h
--- 25/include/asm-i386/page.h~legacy_va_layout-docs 2004-08-01 18:02:55.379287168 -0700
+++ 25-akpm/include/asm-i386/page.h 2004-08-01 21:20:13.260655656 -0700
@@ -118,6 +118,8 @@ static __inline__ int get_order(unsigned
extern int devmem_is_allowed(unsigned long pagenr);
+extern int sysctl_legacy_va_layout;
+
#endif /* __ASSEMBLY__ */
#ifdef __ASSEMBLY__
@@ -147,8 +149,6 @@ extern int devmem_is_allowed(unsigned lo
((current->personality & READ_IMPLIES_EXEC) ? VM_EXEC : 0 ) | \
VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC)
-
-
#endif /* __KERNEL__ */
#endif /* _I386_PAGE_H */
diff -puN arch/i386/mm/mmap.c~legacy_va_layout-docs arch/i386/mm/mmap.c
--- 25/arch/i386/mm/mmap.c~legacy_va_layout-docs 2004-08-01 18:02:55.381286864 -0700
+++ 25-akpm/arch/i386/mm/mmap.c 2004-08-01 18:02:55.388285800 -0700
@@ -35,6 +35,8 @@
#define MIN_GAP (128*1024*1024)
#define MAX_GAP (TASK_SIZE/6*5)
+int sysctl_legacy_va_layout;
+
static inline unsigned long mmap_base(struct mm_struct *mm)
{
unsigned long gap = current->rlim[RLIMIT_STACK].rlim_cur;
@@ -57,7 +59,8 @@ 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 (sysctl_legacy_va_layout || (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;
_