From: Michael Neuling <mikey@neuling.org>
Date: Fri, 5 Mar 2010 21:42:57 +0000 (-0800)
Subject: exec: create initial stack independent of PAGE_SIZE
X-Git-Tag: v2.6.34-rc1~120
X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=commitdiff_plain;h=5ef097dd7ba4eab8b4f0026d85fcef9fe23b821f

exec: create initial stack independent of PAGE_SIZE

Currently we create the initial stack based on the PAGE_SIZE.  This is
unnecessary.

This creates this initial stack independent of the PAGE_SIZE.

It also bumps up the number of 4k pages allocated from 20 to 32, to
align with 64K page systems.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Cc: Helge Deller <deller@gmx.de>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Americo Wang <xiyou.wangcong@gmail.com>
Cc: Anton Blanchard <anton@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/fs/exec.c b/fs/exec.c
index 6348d79..da2b31d 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -556,8 +556,6 @@ static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
 	return 0;
 }
 
-#define EXTRA_STACK_VM_PAGES	20	/* random */
-
 /*
  * Finalizes the stack vm_area_struct. The flags and permissions are updated,
  * the stack is optionally relocated, and some extra space is added.
@@ -632,7 +630,7 @@ int setup_arg_pages(struct linux_binprm *bprm,
 			goto out_unlock;
 	}
 
-	stack_expand = EXTRA_STACK_VM_PAGES * PAGE_SIZE;
+	stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */
 	stack_size = vma->vm_end - vma->vm_start;
 	/*
 	 * Align this down to a page boundary as expand_stack