Implement crashkernel=auto

This series of patch implements automatically reserved memory for crashkernel,
by introducing a new boot option "crashkernel=auto". This idea is from Neil.

In case of breaking user-space applications, it modifies this boot option after
it decides how much memory should be reserved.

On different arch, the threshold and reserved memory size is different. Please
refer patch 7/7 which contains an update for the documentation.

Note: This patchset was only tested on x86_64 with differernt memory sizes.

Signed-off-by: WANG Cong <amwang@redhat.com>
Cc: Neil Horman <nhorman@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Anton Vorontsov <avorontsov@ru.mvista.com>

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/