kybaaz/linux-xiaomi-chiron
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

mm, debug_pagealloc: use a page type instead of page_ext flag

Browse source 
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>
This commit is contained in:
Vlastimil Babka 2019-07-11 20:55:13 -07:00 • committed by Linus Torvalds
parent 4462b32c92
commit 3972f6bb1c
7 changed files with 17 additions and 54 deletions
Download patch file Download diff file Expand all files Collapse all files

10
include/linux/mm.h
View file

@ -2862,8 +2862,6 @@ extern long copy_huge_page_from_user(struct page *dst_page,
bool allow_pagefault);
#endif /* CONFIG_TRANSPARENT_HUGEPAGE || CONFIG_HUGETLBFS */
extern struct page_ext_operations debug_guardpage_ops;
#ifdef CONFIG_DEBUG_PAGEALLOC
extern unsigned int _debug_guardpage_minorder;
DECLARE_STATIC_KEY_FALSE(_debug_guardpage_enabled);
@ -2880,16 +2878,10 @@ static inline bool debug_guardpage_enabled(void)
static inline bool page_is_guard(struct page *page)
{
struct page_ext *page_ext;
if (!debug_guardpage_enabled())
return false;
page_ext = lookup_page_ext(page);
if (unlikely(!page_ext))
return false;
return test_bit(PAGE_EXT_DEBUG_GUARD, &page_ext->flags);
return PageGuard(page);
}
#else
static inline unsigned int debug_guardpage_minorder(void) { return 0; }

6
include/linux/page-flags.h
View file

@ -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);

1
include/linux/page_ext.h
View file

@ -17,7 +17,6 @@ struct page_ext_operations {
#ifdef CONFIG_PAGE_EXTENSION
enum page_ext_flags {
PAGE_EXT_DEBUG_GUARD,
PAGE_EXT_OWNER,
#if defined(CONFIG_IDLE_PAGE_TRACKING) && !defined(CONFIG_64BIT)
PAGE_EXT_YOUNG,