The patch titled
Subject: mm: mark pages in use for page tables
has been added to the -mm tree. Its filename is
mm-mark-pages-in-use-for-page-tables.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-mark-pages-in-use-for-page-tables.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-mark-pages-in-use-for-page-tables.patch
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------------------------------------------------------
From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
Subject: mm: mark pages in use for page tables
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@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Jérôme Glisse <jglisse@xxxxxxxxxx>
Cc: Lai Jiangshan <jiangshanlai@xxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/page.c | 2 ++
include/linux/mm.h | 2 ++
include/linux/page-flags.h | 6 ++++++
include/uapi/linux/kernel-page-flags.h | 2 +-
tools/vm/page-types.c | 1 +
5 files changed, 12 insertions(+), 1 deletion(-)
diff -puN fs/proc/page.c~mm-mark-pages-in-use-for-page-tables fs/proc/page.c
--- a/fs/proc/page.c~mm-mark-pages-in-use-for-page-tables
+++ a/fs/proc/page.c
@@ -154,6 +154,8 @@ u64 stable_page_flags(struct page *page)
if (PageBalloon(page))
u |= 1 << KPF_BALLOON;
+ if (PageTable(page))
+ u |= 1 << KPF_PGTABLE;
if (page_is_idle(page))
u |= 1 << KPF_IDLE;
diff -puN include/linux/mm.h~mm-mark-pages-in-use-for-page-tables include/linux/mm.h
--- a/include/linux/mm.h~mm-mark-pages-in-use-for-page-tables
+++ a/include/linux/mm.h
@@ -1842,6 +1842,7 @@ static inline bool pgtable_page_ctor(str
{
if (!ptlock_init(page))
return false;
+ __SetPageTable(page);
inc_zone_page_state(page, NR_PAGETABLE);
return true;
}
@@ -1849,6 +1850,7 @@ static inline bool pgtable_page_ctor(str
static inline void pgtable_page_dtor(struct page *page)
{
pte_lock_deinit(page);
+ __ClearPageTable(page);
dec_zone_page_state(page, NR_PAGETABLE);
}
diff -puN include/linux/page-flags.h~mm-mark-pages-in-use-for-page-tables include/linux/page-flags.h
--- a/include/linux/page-flags.h~mm-mark-pages-in-use-for-page-tables
+++ a/include/linux/page-flags.h
@@ -655,6 +655,7 @@ PAGEFLAG_FALSE(DoubleMap)
#define PG_buddy 0x00000080
#define PG_balloon 0x00000100
#define PG_kmemcg 0x00000200
+#define PG_table 0x00000400
#define PageType(page, flag) \
((page->page_type & (PAGE_TYPE_BASE | flag)) == PAGE_TYPE_BASE)
@@ -693,6 +694,11 @@ PAGE_TYPE_OPS(Balloon, balloon)
*/
PAGE_TYPE_OPS(Kmemcg, kmemcg)
+/*
+ * 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);
diff -puN include/uapi/linux/kernel-page-flags.h~mm-mark-pages-in-use-for-page-tables include/uapi/linux/kernel-page-flags.h
--- a/include/uapi/linux/kernel-page-flags.h~mm-mark-pages-in-use-for-page-tables
+++ a/include/uapi/linux/kernel-page-flags.h
@@ -35,6 +35,6 @@
#define KPF_BALLOON 23
#define KPF_ZERO_PAGE 24
#define KPF_IDLE 25
-
+#define KPF_PGTABLE 26
#endif /* _UAPILINUX_KERNEL_PAGE_FLAGS_H */
diff -puN tools/vm/page-types.c~mm-mark-pages-in-use-for-page-tables tools/vm/page-types.c
--- a/tools/vm/page-types.c~mm-mark-pages-in-use-for-page-tables
+++ a/tools/vm/page-types.c
@@ -131,6 +131,7 @@ static const char * const page_flag_name
[KPF_KSM] = "x:ksm",
[KPF_THP] = "t:thp",
[KPF_BALLOON] = "o:balloon",
+ [KPF_PGTABLE] = "g:pgtable",
[KPF_ZERO_PAGE] = "z:zero_page",
[KPF_IDLE] = "i:idle_page",
_
Patches currently in -mm which might be from mawilcox@xxxxxxxxxxxxx are
lib-test_bitmapc-fix-bitmap-optimisation-tests-to-report-errors-correctly.patch
slab-__gfp_zero-is-incompatible-with-a-constructor.patch
s390-use-_refcount-for-pgtables.patch
mm-split-page_type-out-from-_mapcount.patch
mm-mark-pages-in-use-for-page-tables.patch
mm-switch-s_mem-and-slab_cache-in-struct-page.patch
mm-move-private-union-within-struct-page.patch
mm-move-_refcount-out-of-struct-page-union.patch
mm-combine-first-three-unions-in-struct-page.patch
mm-use-page-deferred_list.patch
mm-move-lru-union-within-struct-page.patch
mm-combine-lru-and-main-union-in-struct-page.patch
mm-improve-struct-page-documentation.patch
mm-add-pt_mm-to-struct-page.patch
mm-add-hmm_data-to-struct-page.patch
slabslub-remove-rcu_head-size-checks.patch
slub-remove-kmem_cache-reserved.patch
slub-remove-reserved-file-from-sysfs.patch
mm-distinguish-vmalloc-pages.patch
ida-remove-simple_ida_lock.patch
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