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authorMatthew Wilcox <mawilcox@microsoft.com>2018-06-07 17:08:18 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2018-06-07 17:34:37 -0700
commit6e292b9be7f4358985ce33ae1f59ab30a8c09e08 (patch)
tree857ddd791e19272b368e673bb192577a6c5d3e9c /kernel/crash_core.c
parent620b4e903179d58342503fa09d9c680d93bf7db8 (diff)
mm: split page_type out from _mapcount
We're already using a union of many fields here, so stop abusing the _mapcount and make page_type its own field. That implies renaming some of the machinery that creates PageBuddy, PageBalloon and PageKmemcg; bring back the PG_buddy, PG_balloon and PG_kmemcg names. As suggested by Kirill, make page_type a bitmask. Because it starts out life as -1 (thanks to sharing the storage with _mapcount), setting a page flag means clearing the appropriate bit. This gives us space for probably twenty or so extra bits (depending how paranoid we want to be about _mapcount underflow). Link: http://lkml.kernel.org/r/20180518194519.3820-3-willy@infradead.org Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com> Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Christoph Lameter <cl@linux.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Jérôme Glisse <jglisse@redhat.com> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Andrey Ryabinin <aryabinin@virtuozzo.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'kernel/crash_core.c')
-rw-r--r--kernel/crash_core.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index f7674d676889..b66aced5e8c2 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -460,6 +460,7 @@ static int __init crash_save_vmcoreinfo_init(void)
VMCOREINFO_NUMBER(PG_hwpoison);
#endif
VMCOREINFO_NUMBER(PG_head_mask);
+#define PAGE_BUDDY_MAPCOUNT_VALUE (~PG_buddy)
VMCOREINFO_NUMBER(PAGE_BUDDY_MAPCOUNT_VALUE);
#ifdef CONFIG_HUGETLB_PAGE
VMCOREINFO_NUMBER(HUGETLB_PAGE_DTOR);