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authorVlastimil Babka <vbabka@suse.cz>2019-07-12 06:55:13 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2019-07-12 21:05:43 +0300
commit3972f6bb1c6ae1d32dcf2e4ff635d24b77f26dcb (patch)
tree24a0c4a24d8e1afdcb7ca5dd088c1bd4d191a9b9 /include/linux/page-flags.h
parent4462b32c9285b521ef378907aa66a5ca485aae41 (diff)
downloadlinux-3972f6bb1c6ae1d32dcf2e4ff635d24b77f26dcb.tar.xz
mm, debug_pagealloc: use a page type instead of page_ext flag
When debug_pagealloc is enabled, we currently allocate the page_ext array to mark guard pages with the PAGE_EXT_DEBUG_GUARD flag. Now that we have the page_type field in struct page, we can use that instead, as guard pages are neither PageSlab nor mapped to userspace. This reduces memory overhead when debug_pagealloc is enabled and there are no other features requiring the page_ext array. Link: http://lkml.kernel.org/r/20190603143451.27353-4-vbabka@suse.cz Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/page-flags.h')
-rw-r--r--include/linux/page-flags.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h
index 9f8712a4b1a5..b848517da64c 100644
--- a/include/linux/page-flags.h
+++ b/include/linux/page-flags.h
@@ -703,6 +703,7 @@ PAGEFLAG_FALSE(DoubleMap)
#define PG_offline 0x00000100
#define PG_kmemcg 0x00000200
#define PG_table 0x00000400
+#define PG_guard 0x00000800
#define PageType(page, flag) \
((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
@@ -754,6 +755,11 @@ PAGE_TYPE_OPS(Kmemcg, kmemcg)
*/
PAGE_TYPE_OPS(Table, table)
+/*
+ * Marks guardpages used with debug_pagealloc.
+ */
+PAGE_TYPE_OPS(Guard, guard)
+
extern bool is_free_buddy_page(struct page *page);
__PAGEFLAG(Isolated, isolated, PF_ANY);