Messages in this thread | | | Date | Sat, 10 Mar 2012 11:27:41 +0800 | From | Cong Wang <> | Subject | Re: [PATCH] kdump x86: fix total mem size calculation for reservation |
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On 03/09/2012 04:30 PM, Dave Young wrote: > 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. >
Makes sense for me!
> -static inline unsigned long long get_total_mem(void) > -{ > - unsigned long long total; > - > - total = max_pfn - min_low_pfn; > - printk("hidave: memsize=%llu\n", memblock_phys_mem_size());
This debugging line does not exist... so this patch can't be applied.
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