linux-kernel - [PATCH RFC 3/6] kexec: export PG

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Date:   Wed, 14 Nov 2018 22:17:01 +0100
From:   David Hildenbrand <david@...hat.com>
To:     linux-mm@...ck.org
Cc:     linux-kernel@...r.kernel.org, linux-doc@...r.kernel.org,
        devel@...uxdriverproject.org, linux-fsdevel@...r.kernel.org,
        linux-pm@...r.kernel.org, xen-devel@...ts.xenproject.org,
        David Hildenbrand <david@...hat.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Dave Young <dyoung@...hat.com>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Baoquan He <bhe@...hat.com>, Omar Sandoval <osandov@...com>,
        Arnd Bergmann <arnd@...db.de>,
        Matthew Wilcox <willy@...radead.org>,
        Michal Hocko <mhocko@...e.com>,
        "Michael S. Tsirkin" <mst@...hat.com>
Subject: [PATCH RFC 3/6] kexec: export PG_offline to VMCOREINFO

Let's export PG_offline via PAGE_OFFLINE_MAPCOUNT_VALUE, so
makedumpfile can directly skip pages that are logically offline and the
content therefore stale.

Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Dave Young <dyoung@...hat.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>
Cc: Baoquan He <bhe@...hat.com>
Cc: Omar Sandoval <osandov@...com>
Cc: Arnd Bergmann <arnd@...db.de>
Cc: Matthew Wilcox <willy@...radead.org>
Cc: Michal Hocko <mhocko@...e.com>
Cc: "Michael S. Tsirkin" <mst@...hat.com>
Signed-off-by: David Hildenbrand <david@...hat.com>
---
 kernel/crash_core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 933cb3e45b98..093c9f917ed0 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -464,6 +464,8 @@ static int __init crash_save_vmcoreinfo_init(void)
 	VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
 #ifdef CONFIG_HUGETLB_PAGE
 	VMCOREINFO_NUMBER(HUGETLB_PAGE_DTOR);
+#define PAGE_OFFLINE_MAPCOUNT_VALUE	(~PG_offline)
+	VMCOREINFO_NUMBER(PAGE_OFFLINE_MAPCOUNT_VALUE);
 #endif
 
 	arch_crash_save_vmcoreinfo();
-- 
2.17.2