]> git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/commit
kdump x86: fix total mem size calculation for reservation
authorDave Young <dyoung@redhat.com>
Wed, 28 Mar 2012 21:42:47 +0000 (14:42 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Thu, 29 Mar 2012 00:14:36 +0000 (17:14 -0700)
commit09c71bfd8384278c42f56380365940508194cec0
tree3d11eea3bf9c6b2cad6a36755d155f31a0e229fe
parenteaa3be6add6f327ab0a633e4fee8e6f2cc8c8a4c
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 <dyoung@redhat.com>
Reviewed-by: WANG Cong <xiyou.wangcong@gmail.com>
Reviewed-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
arch/x86/kernel/setup.c