kexec: save PG_head_mask in VMCOREINFO
authorPetr Tesarik <ptesarik@suse.cz>
Mon, 23 Jun 2014 20:22:03 +0000 (13:22 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Mon, 23 Jun 2014 23:47:43 +0000 (16:47 -0700)
commitb3acc56bfe1287c6b666e80edc70b89eea2a1a80
tree2ee8421399cda3bb043396d7f70aa9a2d86c9855
parent8d056c48e486249e6487910b83e0f3be7c14acf7
kexec: save PG_head_mask in VMCOREINFO

To allow filtering of huge pages, makedumpfile must be able to identify
them in the dump.  This can be done by checking the appropriate page
flag, so communicate its value to makedumpfile through the VMCOREINFO
interface.

There's only one small catch.  Depending on how many page flags are
available on a given architecture, this bit can be called PG_head or
PG_compound.

I sent a similar patch back in 2012, but Eric Biederman did not like
using an #ifdef.  So, this time I'm adding a common symbol
(PG_head_mask) instead.

See https://lkml.org/lkml/2012/11/28/91 for the previous version.

Signed-off-by: Petr Tesarik <ptesarik@suse.cz>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Alexey Kardashevskiy <aik@ozlabs.ru>
Cc: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/linux/page-flags.h
kernel/kexec.c