From: Ingo Molnar <mingo@elte.hu>
- fall back to the bottom-up layout if the stack can grow unlimited
(if the stack ulimit has been set to RLIM_INFINITY)
- try the bottom-up allocator if the top-down allocator fails - this can
utilize the hole between the true bottom of the stack and its ulimit,
as a last-resort effort.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/arch/i386/mm/mmap.c | 5 +++--
25-akpm/mm/mmap.c | 23 ++++++++++++++++++-----
2 files changed, 21 insertions(+), 7 deletions(-)
diff -puN arch/i386/mm/mmap.c~flexible-mmap-updatepatch-267-mm5 arch/i386/mm/mmap.c
--- 25/arch/i386/mm/mmap.c~flexible-mmap-updatepatch-267-mm5 2004-07-26 23:22:37.941873328 -0700
+++ 25-akpm/arch/i386/mm/mmap.c 2004-07-26 23:22:37.946872568 -0700
@@ -55,9 +55,10 @@ void arch_pick_mmap_layout(struct mm_str
{
/*
* Fall back to the standard layout if the personality
- * bit is set:
+ * bit is set, or if the expected stack growth is unlimited:
*/
- if (current->personality & ADDR_COMPAT_LAYOUT) {
+ if ((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;
mm->unmap_area = arch_unmap_area;
diff -puN mm/mmap.c~flexible-mmap-updatepatch-267-mm5 mm/mmap.c
--- 25/mm/mmap.c~flexible-mmap-updatepatch-267-mm5 2004-07-26 23:22:37.943873024 -0700
+++ 25-akpm/mm/mmap.c 2004-07-26 23:22:37.947872416 -0700
@@ -1081,13 +1081,13 @@ void arch_unmap_area(struct vm_area_stru
* stack's low limit (the base):
*/
unsigned long
-arch_get_unmapped_area_topdown(struct file *filp, unsigned long addr,
- unsigned long len, unsigned long pgoff,
- unsigned long flags)
+arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
+ const unsigned long len, const unsigned long pgoff,
+ const unsigned long flags)
{
struct vm_area_struct *vma, *prev_vma;
struct mm_struct *mm = current->mm;
- unsigned long base = mm->mmap_base;
+ unsigned long base = mm->mmap_base, addr = addr0;
int first_time = 1;
/* requested length too big for entire address space */
@@ -1149,7 +1149,20 @@ fail:
first_time = 0;
goto try_again;
}
- return -ENOMEM;
+ /*
+ * A failed mmap() very likely causes application failure,
+ * so fall back to the bottom-up function here. This scenario
+ * can happen with large stack limits and large mmap()
+ * allocations.
+ */
+ mm->free_area_cache = TASK_UNMAPPED_BASE;
+ addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
+ /*
+ * Restore the topdown base:
+ */
+ mm->free_area_cache = base;
+
+ return addr;
}
void arch_unmap_area_topdown(struct vm_area_struct *area)
_