From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
Define a new PageTable bit in the page_type and use it to mark pages in
use as page tables.
Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
---
include/linux/mm.h | 2 ++
include/linux/page-flags.h | 6 ++++++
2 files changed, 8 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index ad06d42adb1a..7a15042d6828 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1829,6 +1829,7 @@ 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;
}
@@ -1836,6 +1837,7 @@ 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);
}
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 8142ab716e90..ac6bab90849c 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -644,6 +644,7 @@ PAGEFLAG_FALSE(DoubleMap)
#define PG_balloon 0x00000100
#define PG_kmemcg 0x00000200
#define PG_vmalloc 0x00000400
+#define PG_table 0x00000800
#define PageType(page, flag) \
((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
@@ -687,6 +688,11 @@ PAGE_TYPE_OPS(Kmemcg, kmemcg)
*/
PAGE_TYPE_OPS(Vmalloc, vmalloc)
+/*
+ * Marks pages in use as page tables.
+ */
+PAGE_TYPE_OPS(Table, table)
+
extern bool is_free_buddy_page(struct page *page);
__PAGEFLAG(Isolated, isolated, PF_ANY);
--
2.16.1
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