From 09c71bfd8384278c42f56380365940508194cec0 Mon Sep 17 00:00:00 2001 From: Dave Young Date: Wed, 28 Mar 2012 14:42:47 -0700 Subject: [PATCH] kdump x86: fix total mem size calculation for reservation 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. Signed-off-by: Dave Young Reviewed-by: WANG Cong Reviewed-by: Simon Horman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86/kernel/setup.c | 11 +---------- 1 file changed, 1 insertion(+), 10 deletions(-) diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index 88638883176a..ab77aae4ad9b 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -509,15 +509,6 @@ static void __init memblock_x86_reserve_range_setup_data(void) #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(void) 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);