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>
DESC
legacy_va_layout docs
EDESC
- Add documentation.
- It's an x86-only feature, so don't offer the sysctl on other architectures.
DESC
legacy_va_layout-docs-fix
EDESC
DESC
legacy_va_layout compile error with SYSCTL=n
EDESC
From: William Lee Irwin III <wli@holomorphy.com>
hugetlb CONFIG_SYSCTL=n fix, take 2: the real thing.
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/Documentation/filesystems/proc.txt | 6 ++++++
25-akpm/arch/i386/mm/mmap.c | 3 ++-
25-akpm/include/asm-i386/page.h | 4 ++--
25-akpm/include/linux/mm.h | 6 ++++++
25-akpm/include/linux/sysctl.h | 1 +
25-akpm/kernel/sysctl.c | 17 +++++++++++++++++
25-akpm/mm/hugetlb.c | 2 +-
7 files changed, 35 insertions(+), 4 deletions(-)
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 2004-08-20 01:25:11.107792128 -0700
+++ 25-akpm/arch/i386/mm/mmap.c 2004-08-20 01:25:11.125789392 -0700
@@ -57,7 +57,8 @@ 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 ((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 2004-08-20 01:25:11.110791672 -0700
+++ 25-akpm/include/linux/mm.h 2004-08-20 01:25:11.127789088 -0700
@@ -26,6 +26,12 @@ extern void * high_memory;
extern unsigned long vmalloc_earlyreserve;
extern int page_cluster;
+#ifdef CONFIG_SYSCTL
+extern int sysctl_legacy_va_layout;
+#else
+#define sysctl_legacy_va_layout 0
+#endif
+
#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 2004-08-20 01:25:11.113791216 -0700
+++ 25-akpm/include/linux/sysctl.h 2004-08-20 01:25:11.128788936 -0700
@@ -167,6 +167,7 @@ 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 2004-08-20 01:25:11.116790760 -0700
+++ 25-akpm/kernel/sysctl.c 2004-08-20 01:25:11.131788480 -0700
@@ -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>
@@ -152,6 +153,10 @@ 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
@@ -820,6 +825,18 @@ 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 }
};
diff -puN Documentation/filesystems/proc.txt~sysctl-tunable-for-flexmmap Documentation/filesystems/proc.txt
--- 25/Documentation/filesystems/proc.txt~sysctl-tunable-for-flexmmap 2004-08-20 01:25:11.118790456 -0700
+++ 25-akpm/Documentation/filesystems/proc.txt 2004-08-20 01:25:11.133788176 -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 32-bit mmap mmap layout - the kernel
+will use the legacy (2.4) layout for all processes.
+
lower_zone_protection
---------------------
diff -puN include/asm-i386/page.h~sysctl-tunable-for-flexmmap include/asm-i386/page.h
--- 25/include/asm-i386/page.h~sysctl-tunable-for-flexmmap 2004-08-20 01:25:11.120790152 -0700
+++ 25-akpm/include/asm-i386/page.h 2004-08-20 01:25:11.134788024 -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 mm/hugetlb.c~sysctl-tunable-for-flexmmap mm/hugetlb.c
--- 25/mm/hugetlb.c~sysctl-tunable-for-flexmmap 2004-08-20 01:25:11.122789848 -0700
+++ 25-akpm/mm/hugetlb.c 2004-08-20 01:25:11.135787872 -0700
@@ -123,6 +123,7 @@ static int __init hugetlb_setup(char *s)
}
__setup("hugepages=", hugetlb_setup);
+#ifdef CONFIG_SYSCTL
static void update_and_free_page(struct page *page)
{
int i;
@@ -188,7 +189,6 @@ static unsigned long set_max_huge_pages(
return nr_huge_pages;
}
-#ifdef CONFIG_SYSCTL
int hugetlb_sysctl_handler(struct ctl_table *table, int write,
struct file *file, void __user *buffer,
size_t *length, loff_t *ppos)
_