From 1d40a5ea01d53251c23c7be541d3f4a656cfc537 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Thu, 7 Jun 2018 17:08:23 -0700 Subject: mm: mark pages in use for page tables MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Define a new PageTable bit in the page_type and use it to mark pages in use as page tables. This can be helpful when debugging crashdumps or analysing memory fragmentation. Add a KPF flag to report these pages to userspace and update page-types.c to interpret that flag. Note that only pages currently accounted as NR_PAGETABLES are tracked as PageTable; this does not include pgd/p4d/pud/pmd pages. Those will be the subject of a later patch. Link: http://lkml.kernel.org/r/20180518194519.3820-4-willy@infradead.org Signed-off-by: Matthew Wilcox Acked-by: Kirill A. Shutemov Acked-by: Vlastimil Babka Cc: Christoph Lameter Cc: Dave Hansen Cc: Jérôme Glisse Cc: Lai Jiangshan Cc: Martin Schwidefsky Cc: Pekka Enberg Cc: Randy Dunlap Cc: Andrey Ryabinin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/mm.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'include/linux/mm.h') diff --git a/include/linux/mm.h b/include/linux/mm.h index d1dc618a56bf..1dd588b7c649 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1851,6 +1851,7 @@ static inline bool pgtable_page_ctor(struct page *page) { if (!ptlock_init(page)) return false; + __SetPageTable(page); inc_zone_page_state(page, NR_PAGETABLE); return true; } @@ -1858,6 +1859,7 @@ static inline bool pgtable_page_ctor(struct page *page) static inline void pgtable_page_dtor(struct page *page) { pte_lock_deinit(page); + __ClearPageTable(page); dec_zone_page_state(page, NR_PAGETABLE); } -- cgit v1.2.2