crashkernel reservation need know the total memory size. Current get_total_mem
simply use max_pfn - min_low_pfn. It is wrong because it will including
memory holes in the middle.
Especially for kvm guest with memory > 0xe0000000, there's below in qemu code:
qemu split memory as below:
if (ram_size >= 0xe0000000 ) {
above_4g_mem_size = ram_size - 0xe0000000;
below_4g_mem_size = 0xe0000000;
} else {
below_4g_mem_size = ram_size;
}
So for 4G mem guest, seabios will insert a 512M usable region beyond of 4G.
Thus in above case max_pfn - min_low_pfn will be more than original memsize.
Fixing this issue by using memblock_phys_mem_size() to get the total memsize.
[v1 -> v2]: refresh the patch based on latest linus tree
Signed-off-by: Dave Young <dyoung at redhat.com>
Reviewed-by: WANG Cong <xiyou.wangcong at gmail.com>
---
arch/x86/kernel/setup.c | 11 +----------
1 file changed, 1 insertion(+), 10 deletions(-)
--- linux-2.6.orig/arch/x86/kernel/setup.c 2012-03-04 03:46:35.000000000 +0800
+++ linux-2.6/arch/x86/kernel/setup.c 2012-03-10 12:44:58.133300788 +0800
@@ -509,15 +509,6 @@ static void __init memblock_x86_reserve_
#ifdef CONFIG_KEXEC
-static inline unsigned long long get_total_mem(void)
-{
- unsigned long long total;
-
- total = max_pfn - min_low_pfn;
-
- return total << PAGE_SHIFT;
-}
-
/*
* Keep the crash kernel below this limit. On 32 bits earlier kernels
* would limit the kernel to the low 512 MiB due to mapping restrictions.
@@ -536,7 +527,7 @@ static void __init reserve_crashkernel(v
unsigned long long crash_size, crash_base;
int ret;
- total_mem = get_total_mem();
+ total_mem = memblock_phys_mem_size();
ret = parse_crashkernel(boot_command_line, total_mem,
&crash_size, &crash_base);
--
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