On Mon, Oct 14, 2013 at 4:46 AM, WANG Chao <chaowang at redhat.com> wrote: > Now crashkernel=X will fail out if there's not enough memory at > low (below 896M). What makes sense for crashkernel=X would be: > > - First try to reserve X below 896M (for being compatible with old > kexec-tools). > - If fails, try to reserve X below 4G (swiotlb need to stay below 4G). > - If fails, try to reserve X from MAXMEM top down. > > diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c > index f0de629..38e6c1f 100644 > --- a/arch/x86/kernel/setup.c > +++ b/arch/x86/kernel/setup.c > @@ -593,6 +593,20 @@ static void __init reserve_crashkernel(void) > high ? CRASH_KERNEL_ADDR_HIGH_MAX : > CRASH_KERNEL_ADDR_LOW_MAX, > crash_size, alignment); > + /* > + * crashkernel=X reserve below 896M fails? Try below 4G > + */ > + if (!high && !crash_base) > + crash_base = memblock_find_in_range(alignment, > + (1ULL << 32), > + crash_size, alignment); Another problem, it would allocate range in [0,4g) for 32bit, if the user have crashkernel=512M or plus. > + /* > + * crashkernel=X reserve below 4G fails? Try MAXMEM > + */ > + if (!high && !crash_base) > + crash_base = memblock_find_in_range(alignment, > + CRASH_KERNEL_ADDR_HIGH_MAX, > + crash_size, alignment); > > if (!crash_base) { > pr_info("crashkernel reservation failed - No suitable area found.\n"); Yinghai