From: Dave Young <hidave.darkstar@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@elte.hu, hpa@zytor.com, akpm@linux-foundation.org,
yhlu.kernel@gmail.com, x86@kernel.org, linux-mm@kvack.org
Subject: [PATCH V2] i386 : vmalloc size fix
Date: Tue, 29 Jul 2008 15:54:41 +0800 [thread overview]
Message-ID: <20080729075441.GA3075@darkstar> (raw)
v2 based on the ported version of ingo, changes:
remove unused VMALLOC_RESERVE macro in page_32.h
--
Booting kernel with vmalloc=[any size<=16m] will oops on my pc (i386/1G memory).
BUG_ON in arch/x86/mm/init_32.c triggered:
BUG_ON((unsigned long)high_memory > VMALLOC_START);
It's due to the vm area hole.
In include/asm-x86/pgtable_32.h:
#define VMALLOC_OFFSET (8 * 1024 * 1024)
#define VMALLOC_START (((unsigned long)high_memory + 2 * VMALLOC_OFFSET - 1) \
& ~(VMALLOC_OFFSET - 1))
There's several related point:
1. MAXMEM :
(-__PAGE_OFFSET - __VMALLOC_RESERVE).
The space after VMALLOC_END is included as well, I set it to
(VMALLOC_END - PAGE_OFFSET - __VMALLOC_RESERVE)
2. VMALLOC_OFFSET is not considered in __VMALLOC_RESERVE
fixed by adding VMALLOC_OFFSET to it.
3. VMALLOC_START :
(((unsigned long)high_memory + 2 * VMALLOC_OFFSET - 1) & ~(VMALLOC_OFFSET - 1))
So it's not always 8M, bigger than 8M possible.
I set it to ((unsigned long)high_memory + VMALLOC_OFFSET)
4. the VMALLOC_RESERVE is an unused macro, so remove it here.
Signed-off-by: Dave Young <hidave.darkstar@gmail.com>
arch/x86/mm/pgtable_32.c | 3 ++-
include/asm-x86/page_32.h | 3 ---
include/asm-x86/pgtable_32.h | 5 +++--
3 files changed, 5 insertions(+), 6 deletions(-)
Index: linux-2.6/arch/x86/mm/pgtable_32.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/pgtable_32.c 2008-07-29 14:43:02.000000000 +0800
+++ linux-2.6/arch/x86/mm/pgtable_32.c 2008-07-29 14:44:43.000000000 +0800
@@ -123,7 +123,8 @@
if (!arg)
return -EINVAL;
- __VMALLOC_RESERVE = memparse(arg, &arg);
+ /* Add VMALLOC_OFFSET to the parsed value due to vm area guard hole*/
+ __VMALLOC_RESERVE = memparse(arg, &arg) + VMALLOC_OFFSET;
return 0;
}
early_param("vmalloc", parse_vmalloc);
Index: linux-2.6/include/asm-x86/page_32.h
===================================================================
--- linux-2.6.orig/include/asm-x86/page_32.h 2008-07-29 14:44:13.000000000 +0800
+++ linux-2.6/include/asm-x86/page_32.h 2008-07-29 14:45:15.000000000 +0800
@@ -89,9 +89,6 @@
extern unsigned int __VMALLOC_RESERVE;
extern int sysctl_legacy_va_layout;
-#define VMALLOC_RESERVE ((unsigned long)__VMALLOC_RESERVE)
-#define MAXMEM (-__PAGE_OFFSET - __VMALLOC_RESERVE)
-
extern void find_low_pfn_range(void);
extern unsigned long init_memory_mapping(unsigned long start,
unsigned long end);
Index: linux-2.6/include/asm-x86/pgtable_32.h
===================================================================
--- linux-2.6.orig/include/asm-x86/pgtable_32.h 2008-07-29 14:43:02.000000000 +0800
+++ linux-2.6/include/asm-x86/pgtable_32.h 2008-07-29 14:44:43.000000000 +0800
@@ -56,8 +56,7 @@
* area for the same reason. ;)
*/
#define VMALLOC_OFFSET (8 * 1024 * 1024)
-#define VMALLOC_START (((unsigned long)high_memory + 2 * VMALLOC_OFFSET - 1) \
- & ~(VMALLOC_OFFSET - 1))
+#define VMALLOC_START ((unsigned long)high_memory + VMALLOC_OFFSET)
#ifdef CONFIG_X86_PAE
#define LAST_PKMAP 512
#else
@@ -73,6 +72,8 @@
# define VMALLOC_END (FIXADDR_START - 2 * PAGE_SIZE)
#endif
+#define MAXMEM (VMALLOC_END - PAGE_OFFSET - __VMALLOC_RESERVE)
+
/*
* Define this if things work differently on an i386 and an i486:
* it will (on an i486) warn about kernel memory accesses that are
--
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reply other threads:[~2008-07-29 7:53 UTC|newest]
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