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Groups > linux.kernel > #1702478

[v4 08/15] mm: zero struct pages during initialization

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Add struct page zeroing as a part of initialization of other fields in
__init_single_page().

Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Steven Sistare <steven.sistare@oracle.com>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: Bob Picco <bob.picco@oracle.com>
---
 include/linux/mm.h | 9 +++++++++
 mm/page_alloc.c    | 1 +
 2 files changed, 10 insertions(+)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 46b9ac5e8569..183ac5e733db 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -94,6 +94,15 @@ extern int mmap_rnd_compat_bits __read_mostly;
 #endif
 
 /*
+ * On some architectures it is expensive to call memset() for small sizes.
+ * Those architectures should provide their own implementation of "struct page"
+ * zeroing by defining this macro in <asm/pgtable.h>.
+ */
+#ifndef mm_zero_struct_page
+#define mm_zero_struct_page(pp)  ((void)memset((pp), 0, sizeof(struct page)))
+#endif
+
+/*
  * Default maximum number of active map areas, this limits the number of vmas
  * per mm struct. Users can overwrite this number by sysctl but there is a
  * problem.
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 99b9e2e06319..debea7c0febb 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1168,6 +1168,7 @@ static void free_one_page(struct zone *zone,
 static void __meminit __init_single_page(struct page *page, unsigned long pfn,
 				unsigned long zone, int nid)
 {
+	mm_zero_struct_page(page);
 	set_page_links(page, zone, nid, pfn);
 	init_page_count(page);
 	page_mapcount_reset(page);
-- 
2.13.3

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[v4 00/15] complete deferred page initialization Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:40 +0200
  [v4 14/15] mm: optimize early system hash allocations Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:40 +0200
  [v4 03/15] sparc64/mm: setting fields in deferred pages Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 06/15] sparc64: simplify vmemmap_populate Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 01/15] x86/mm: reserve only exiting low pages Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 02/15] x86/mm: setting fields in deferred pages Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 15/15] mm: debug for raw alloctor Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 09/15] sparc64: optimized struct page zeroing Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 12/15] mm: explicitly zero pagetable memory Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 10/15] x86/kasan: explicitly zero kasan shadow memory Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 04/15] mm: discard memblock data later Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 08/15] mm: zero struct pages during initialization Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 11/15] arm64/kasan: explicitly zero kasan shadow memory Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 07/15] mm: defining memblock_virt_alloc_try_nid_raw Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200
  [v4 05/15] mm: don't accessed uninitialized struct pages Pavel Tatashin <pasha.tatashin@oracle.com> - 2017-08-02 22:50 +0200

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