The patch titled
Subject: mm: distinguish VMalloc pages
has been added to the -mm tree. Its filename is
mm-distinguish-vmalloc-pages.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-distinguish-vmalloc-pages.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-distinguish-vmalloc-pages.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
Subject: mm: distinguish VMalloc pages
For diagnosing various performance and memory-leak problems, it is helpful
to be able to distinguish pages which are in use as VMalloc pages.
Unfortunately, we cannot use the page_type field in struct page, as this
is in use for mapcount by some drivers which map vmalloced pages to
userspace.
Use a special page->mapping value to distinguish VMalloc pages from other
kinds of pages. Also record a pointer to the vm_struct and the offset
within the area in struct page to help reconstruct exactly what this page
is being used for.
Link: http://lkml.kernel.org/r/20180518194519.3820-18-willy@xxxxxxxxxxxxx
Signed-off-by: Matthew Wilcox <mawilcox@xxxxxxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: Jérôme Glisse <jglisse@xxxxxxxxxx>
Cc: "Kirill A . Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Lai Jiangshan <jiangshanlai@xxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/proc/page.c | 2 +
include/linux/mm_types.h | 5 ++++
include/linux/page-flags.h | 25 +++++++++++++++++++++++
include/uapi/linux/kernel-page-flags.h | 1
mm/vmalloc.c | 5 +++-
tools/vm/page-types.c | 1
6 files changed, 38 insertions(+), 1 deletion(-)
diff -puN fs/proc/page.c~mm-distinguish-vmalloc-pages fs/proc/page.c
--- a/fs/proc/page.c~mm-distinguish-vmalloc-pages
+++ a/fs/proc/page.c
@@ -156,6 +156,8 @@ u64 stable_page_flags(struct page *page)
u |= 1 << KPF_BALLOON;
if (PageTable(page))
u |= 1 << KPF_PGTABLE;
+ if (PageVMalloc(page))
+ u |= 1 << KPF_VMALLOC;
if (page_is_idle(page))
u |= 1 << KPF_IDLE;
diff -puN include/linux/mm_types.h~mm-distinguish-vmalloc-pages include/linux/mm_types.h
--- a/include/linux/mm_types.h~mm-distinguish-vmalloc-pages
+++ a/include/linux/mm_types.h
@@ -146,6 +146,11 @@ struct page {
spinlock_t ptl;
#endif
};
+ struct { /* VMalloc pages */
+ struct vm_struct *vm_area;
+ unsigned long vm_offset;
+ unsigned long _vm_id; /* MAPPING_VMalloc */
+ };
struct { /* ZONE_DEVICE pages */
/** @pgmap: Points to the hosting device page map. */
struct dev_pagemap *pgmap;
diff -puN include/linux/page-flags.h~mm-distinguish-vmalloc-pages include/linux/page-flags.h
--- a/include/linux/page-flags.h~mm-distinguish-vmalloc-pages
+++ a/include/linux/page-flags.h
@@ -699,6 +699,31 @@ PAGE_TYPE_OPS(Kmemcg, kmemcg)
*/
PAGE_TYPE_OPS(Table, table)
+/*
+ * vmalloc pages may be mapped to userspace, so we need some other way
+ * to distinguish them from other kinds of pages. Use page->mapping
+ * for this purpose. Values below 0x1000 cannot be real pointers.
+ */
+#define MAPPING_VMalloc (void *)0x440
+
+#define PAGE_MAPPING_OPS(name) \
+static __always_inline int Page##name(struct page *page) \
+{ \
+ return page->mapping == MAPPING_##name; \
+} \
+static __always_inline void __SetPage##name(struct page *page) \
+{ \
+ VM_BUG_ON_PAGE(page->mapping != NULL, page); \
+ page->mapping = MAPPING_##name; \
+} \
+static __always_inline void __ClearPage##name(struct page *page) \
+{ \
+ VM_BUG_ON_PAGE(page->mapping != MAPPING_##name, page); \
+ page->mapping = NULL; \
+}
+
+PAGE_MAPPING_OPS(VMalloc)
+
extern bool is_free_buddy_page(struct page *page);
__PAGEFLAG(Isolated, isolated, PF_ANY);
diff -puN include/uapi/linux/kernel-page-flags.h~mm-distinguish-vmalloc-pages include/uapi/linux/kernel-page-flags.h
--- a/include/uapi/linux/kernel-page-flags.h~mm-distinguish-vmalloc-pages
+++ a/include/uapi/linux/kernel-page-flags.h
@@ -36,5 +36,6 @@
#define KPF_ZERO_PAGE 24
#define KPF_IDLE 25
#define KPF_PGTABLE 26
+#define KPF_VMALLOC 27
#endif /* _UAPILINUX_KERNEL_PAGE_FLAGS_H */
diff -puN mm/vmalloc.c~mm-distinguish-vmalloc-pages mm/vmalloc.c
--- a/mm/vmalloc.c~mm-distinguish-vmalloc-pages
+++ a/mm/vmalloc.c
@@ -1522,7 +1522,7 @@ static void __vunmap(const void *addr, i
for (i = 0; i < area->nr_pages; i++) {
struct page *page = area->pages[i];
- BUG_ON(!page);
+ __ClearPageVMalloc(page);
__free_pages(page, 0);
}
@@ -1692,6 +1692,9 @@ static void *__vmalloc_area_node(struct
area->nr_pages = i;
goto fail;
}
+ __SetPageVMalloc(page);
+ page->vm_area = area;
+ page->vm_offset = i;
area->pages[i] = page;
if (gfpflags_allow_blocking(gfp_mask|highmem_mask))
cond_resched();
diff -puN tools/vm/page-types.c~mm-distinguish-vmalloc-pages tools/vm/page-types.c
--- a/tools/vm/page-types.c~mm-distinguish-vmalloc-pages
+++ a/tools/vm/page-types.c
@@ -132,6 +132,7 @@ static const char * const page_flag_name
[KPF_THP] = "t:thp",
[KPF_BALLOON] = "o:balloon",
[KPF_PGTABLE] = "g:pgtable",
+ [KPF_VMALLOC] = "V:vmalloc",
[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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