[PATCH] mmap topdown fix for large stack limit, large allocation
The topdown changes in 2.6.12-rc1 can cause large allocations with large
stack limit to fail, despite there being space available. The
mmap_base-len is only valid when len >= mmap_base. However, nothing in
topdown allocator checks this. It's only (now) caught at higher level,
which will cause allocation to simply fail. The following change restores
the fallback to bottom-up path, which will allow large allocations with
large stack limit to potentially still succeed.
Signed-off-by: Chris Wright <chrisw@osdl.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/mmap.c b/mm/mmap.c
index 9da23c1..da3fa90 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1267,6 +1267,9 @@
return (mm->free_area_cache = addr-len);
}
+ if (mm->mmap_base < len)
+ goto bottomup;
+
addr = mm->mmap_base-len;
do {
@@ -1288,6 +1291,7 @@
addr = vma->vm_start-len;
} while (len < vma->vm_start);
+bottomup:
/*
* A failed mmap() very likely causes application failure,
* so fall back to the bottom-up function here. This scenario
