[PATCH] ARM: fix bug which lowmem size is limited to 760MB

Yongtaek Lee ytk.lee at samsung.com
Wed Sep 2 22:11:06 PDT 2015


default value of VMALLOC_START was set 0xf0000000 for ARM by commit
0536bdf3. It leads lowmem end address 0xef800000 not 0xf0000000.

VMALLOC_END - (240 << 20) - VMALLOC_OFFSET)
0xff000000 - 0x0f000000 - 0x00800000 = 0xef800000

In case of 768MB ram without CONFIG_HIGHMEM=y, last 8MB could not be
allocated. Kernel log also print out warning message as below.
"Truncating RAM at 80000000-afffffff to -af7fffff (vmalloc region overlap)."

Although it could be solved by state "vmalloc=size" in cmdline but i think
it would be better to change default value to 232 from 240.

Signed-off-by: Yongtaek Lee <ytk.lee at samsung.com>
---
 arch/arm/mm/mmu.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 8348ed6..9a1bab4 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -1040,12 +1040,12 @@ void __init debug_ll_io_init(void)
 #endif
 
 static void * __initdata vmalloc_min =
-	(void *)(VMALLOC_END - (240 << 20) - VMALLOC_OFFSET);
+	(void *)(VMALLOC_END - (232 << 20) - VMALLOC_OFFSET);
 
 /*
  * vmalloc=size forces the vmalloc area to be exactly 'size'
  * bytes. This can be used to increase (or decrease) the vmalloc
- * area - the default is 240m.
+ * area - the default is 232m.
  */
 static int __init early_vmalloc(char *arg)
 {
-- 
1.7.9




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