The patch titled
Subject: mm: differentiate page_mapped() from page_mapcount() for compound pages
has been added to the -mm tree. Its filename is
mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages.patch
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------------------------------------------------------
From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
Subject: mm: differentiate page_mapped() from page_mapcount() for compound pages
Let's define page_mapped() to be true for compound pages if any
sub-pages of the compound page is mapped (with PMD or PTE).
On other hand page_mapcount() return mapcount for this particular small
page.
This will make cases like page_get_anon_vma() behave correctly once we
allow huge pages to be mapped with PTE.
Most users outside core-mm should use page_mapcount() instead of
page_mapped().
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Tested-by: Sasha Levin <sasha.levin@xxxxxxxxxx>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Acked-by: Jerome Marchand <jmarchan@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx>
Cc: Steve Capper <steve.capper@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/arc/mm/cache.c | 4 ++--
arch/arm/mm/flush.c | 2 +-
arch/mips/mm/c-r4k.c | 3 ++-
arch/mips/mm/cache.c | 2 +-
arch/mips/mm/init.c | 6 +++---
arch/sh/mm/cache-sh4.c | 2 +-
arch/sh/mm/cache.c | 8 ++++----
arch/xtensa/mm/tlb.c | 2 +-
fs/proc/page.c | 4 ++--
include/linux/mm.h | 15 +++++++++++++--
mm/filemap.c | 2 +-
11 files changed, 31 insertions(+), 19 deletions(-)
diff -puN arch/arc/mm/cache.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages arch/arc/mm/cache.c
--- a/arch/arc/mm/cache.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages
+++ a/arch/arc/mm/cache.c
@@ -582,7 +582,7 @@ void flush_dcache_page(struct page *page
*/
if (!mapping_mapped(mapping)) {
clear_bit(PG_dc_clean, &page->flags);
- } else if (page_mapped(page)) {
+ } else if (page_mapcount(page)) {
/* kernel reading from page with U-mapping */
unsigned long paddr = (unsigned long)page_address(page);
@@ -819,7 +819,7 @@ void copy_user_highpage(struct page *to,
* Note that while @u_vaddr refers to DST page's userspace vaddr, it is
* equally valid for SRC page as well
*/
- if (page_mapped(from) && addr_not_cache_congruent(kfrom, u_vaddr)) {
+ if (page_mapcount(from) && addr_not_cache_congruent(kfrom, u_vaddr)) {
__flush_dcache_page(kfrom, u_vaddr);
clean_src_k_mappings = 1;
}
diff -puN arch/arm/mm/flush.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages arch/arm/mm/flush.c
--- a/arch/arm/mm/flush.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages
+++ a/arch/arm/mm/flush.c
@@ -330,7 +330,7 @@ void flush_dcache_page(struct page *page
mapping = page_mapping(page);
if (!cache_ops_need_broadcast() &&
- mapping && !page_mapped(page))
+ mapping && !page_mapcount(page))
clear_bit(PG_dcache_clean, &page->flags);
else {
__flush_dcache_page(mapping, page);
diff -puN arch/mips/mm/c-r4k.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages arch/mips/mm/c-r4k.c
--- a/arch/mips/mm/c-r4k.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages
+++ a/arch/mips/mm/c-r4k.c
@@ -587,7 +587,8 @@ static inline void local_r4k_flush_cache
* another ASID than the current one.
*/
map_coherent = (cpu_has_dc_aliases &&
- page_mapped(page) && !Page_dcache_dirty(page));
+ page_mapcount(page) &&
+ !Page_dcache_dirty(page));
if (map_coherent)
vaddr = kmap_coherent(page, addr);
else
diff -puN arch/mips/mm/cache.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages arch/mips/mm/cache.c
--- a/arch/mips/mm/cache.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages
+++ a/arch/mips/mm/cache.c
@@ -106,7 +106,7 @@ void __flush_anon_page(struct page *page
unsigned long addr = (unsigned long) page_address(page);
if (pages_do_alias(addr, vmaddr)) {
- if (page_mapped(page) && !Page_dcache_dirty(page)) {
+ if (page_mapcount(page) && !Page_dcache_dirty(page)) {
void *kaddr;
kaddr = kmap_coherent(page, vmaddr);
diff -puN arch/mips/mm/init.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages arch/mips/mm/init.c
--- a/arch/mips/mm/init.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages
+++ a/arch/mips/mm/init.c
@@ -165,7 +165,7 @@ void copy_user_highpage(struct page *to,
vto = kmap_atomic(to);
if (cpu_has_dc_aliases &&
- page_mapped(from) && !Page_dcache_dirty(from)) {
+ page_mapcount(from) && !Page_dcache_dirty(from)) {
vfrom = kmap_coherent(from, vaddr);
copy_page(vto, vfrom);
kunmap_coherent();
@@ -187,7 +187,7 @@ void copy_to_user_page(struct vm_area_st
unsigned long len)
{
if (cpu_has_dc_aliases &&
- page_mapped(page) && !Page_dcache_dirty(page)) {
+ page_mapcount(page) && !Page_dcache_dirty(page)) {
void *vto = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
memcpy(vto, src, len);
kunmap_coherent();
@@ -205,7 +205,7 @@ void copy_from_user_page(struct vm_area_
unsigned long len)
{
if (cpu_has_dc_aliases &&
- page_mapped(page) && !Page_dcache_dirty(page)) {
+ page_mapcount(page) && !Page_dcache_dirty(page)) {
void *vfrom = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
memcpy(dst, vfrom, len);
kunmap_coherent();
diff -puN arch/sh/mm/cache-sh4.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages arch/sh/mm/cache-sh4.c
--- a/arch/sh/mm/cache-sh4.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages
+++ a/arch/sh/mm/cache-sh4.c
@@ -241,7 +241,7 @@ static void sh4_flush_cache_page(void *a
*/
map_coherent = (current_cpu_data.dcache.n_aliases &&
test_bit(PG_dcache_clean, &page->flags) &&
- page_mapped(page));
+ page_mapcount(page));
if (map_coherent)
vaddr = kmap_coherent(page, address);
else
diff -puN arch/sh/mm/cache.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages arch/sh/mm/cache.c
--- a/arch/sh/mm/cache.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages
+++ a/arch/sh/mm/cache.c
@@ -59,7 +59,7 @@ void copy_to_user_page(struct vm_area_st
unsigned long vaddr, void *dst, const void *src,
unsigned long len)
{
- if (boot_cpu_data.dcache.n_aliases && page_mapped(page) &&
+ if (boot_cpu_data.dcache.n_aliases && page_mapcount(page) &&
test_bit(PG_dcache_clean, &page->flags)) {
void *vto = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
memcpy(vto, src, len);
@@ -78,7 +78,7 @@ void copy_from_user_page(struct vm_area_
unsigned long vaddr, void *dst, const void *src,
unsigned long len)
{
- if (boot_cpu_data.dcache.n_aliases && page_mapped(page) &&
+ if (boot_cpu_data.dcache.n_aliases && page_mapcount(page) &&
test_bit(PG_dcache_clean, &page->flags)) {
void *vfrom = kmap_coherent(page, vaddr) + (vaddr & ~PAGE_MASK);
memcpy(dst, vfrom, len);
@@ -97,7 +97,7 @@ void copy_user_highpage(struct page *to,
vto = kmap_atomic(to);
- if (boot_cpu_data.dcache.n_aliases && page_mapped(from) &&
+ if (boot_cpu_data.dcache.n_aliases && page_mapcount(from) &&
test_bit(PG_dcache_clean, &from->flags)) {
vfrom = kmap_coherent(from, vaddr);
copy_page(vto, vfrom);
@@ -153,7 +153,7 @@ void __flush_anon_page(struct page *page
unsigned long addr = (unsigned long) page_address(page);
if (pages_do_alias(addr, vmaddr)) {
- if (boot_cpu_data.dcache.n_aliases && page_mapped(page) &&
+ if (boot_cpu_data.dcache.n_aliases && page_mapcount(page) &&
test_bit(PG_dcache_clean, &page->flags)) {
void *kaddr;
diff -puN arch/xtensa/mm/tlb.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages arch/xtensa/mm/tlb.c
--- a/arch/xtensa/mm/tlb.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages
+++ a/arch/xtensa/mm/tlb.c
@@ -245,7 +245,7 @@ static int check_tlb_entry(unsigned w, u
page_mapcount(p));
if (!page_count(p))
rc |= TLB_INSANE;
- else if (page_mapped(p))
+ else if (page_mapcount(p))
rc |= TLB_SUSPICIOUS;
} else {
rc |= TLB_INSANE;
diff -puN fs/proc/page.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages fs/proc/page.c
--- a/fs/proc/page.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages
+++ a/fs/proc/page.c
@@ -103,9 +103,9 @@ u64 stable_page_flags(struct page *page)
* pseudo flags for the well known (anonymous) memory mapped pages
*
* Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the
- * simple test in page_mapped() is not enough.
+ * simple test in page_mapcount() is not enough.
*/
- if (!PageSlab(page) && page_mapped(page))
+ if (!PageSlab(page) && page_mapcount(page))
u |= 1 << KPF_MMAP;
if (PageAnon(page))
u |= 1 << KPF_ANON;
diff -puN include/linux/mm.h~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages include/linux/mm.h
--- a/include/linux/mm.h~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages
+++ a/include/linux/mm.h
@@ -938,10 +938,21 @@ static inline pgoff_t page_file_index(st
/*
* Return true if this page is mapped into pagetables.
+ * For compound page it returns true if any subpage of compound page is mapped.
*/
-static inline int page_mapped(struct page *page)
+static inline bool page_mapped(struct page *page)
{
- return atomic_read(&(page)->_mapcount) + compound_mapcount(page) >= 0;
+ int i;
+ if (likely(!PageCompound(page)))
+ return atomic_read(&page->_mapcount) >= 0;
+ page = compound_head(page);
+ if (atomic_read(compound_mapcount_ptr(page)) >= 0)
+ return true;
+ for (i = 0; i < hpage_nr_pages(page); i++) {
+ if (atomic_read(&page[i]._mapcount) >= 0)
+ return true;
+ }
+ return false;
}
/*
diff -puN mm/filemap.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages mm/filemap.c
--- a/mm/filemap.c~mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages
+++ a/mm/filemap.c
@@ -204,7 +204,7 @@ void __delete_from_page_cache(struct pag
__dec_zone_page_state(page, NR_FILE_PAGES);
if (PageSwapBacked(page))
__dec_zone_page_state(page, NR_SHMEM);
- BUG_ON(page_mapped(page));
+ VM_BUG_ON_PAGE(page_mapped(page), page);
/*
* At this point page must be either written or cleaned by truncate.
_
Patches currently in -mm which might be from kirill.shutemov@xxxxxxxxxxxxxxx are
rcu-force-alignment-on-struct-callback_head-rcu_head.patch
mm-make-optimistic-check-for-swapin-readahead-fix.patch
mm-make-swapin-readahead-to-improve-thp-collapse-rate-fix.patch
mm-make-swapin-readahead-to-improve-thp-collapse-rate-fix-2.patch
mm-make-swapin-readahead-to-improve-thp-collapse-rate-fix-3.patch
mm-drop-page-slab_page.patch
slab-slub-use-page-rcu_head-instead-of-page-lru-plus-cast.patch
zsmalloc-use-page-private-instead-of-page-first_page.patch
mm-pack-compound_dtor-and-compound_order-into-one-word-in-struct-page.patch
mm-make-compound_head-robust.patch
mm-make-compound_head-robust-fix.patch
mm-use-unsigned-int-for-page-order.patch
mm-use-unsigned-int-for-compound_dtor-compound_order-on-64bit.patch
page-flags-trivial-cleanup-for-pagetrans-helpers.patch
page-flags-move-code-around.patch
page-flags-introduce-page-flags-policies-wrt-compound-pages.patch
page-flags-introduce-page-flags-policies-wrt-compound-pages-fix.patch
page-flags-introduce-page-flags-policies-wrt-compound-pages-fix-fix.patch
page-flags-introduce-page-flags-policies-wrt-compound-pages-fix-3.patch
page-flags-define-pg_locked-behavior-on-compound-pages.patch
page-flags-define-behavior-of-fs-io-related-flags-on-compound-pages.patch
page-flags-define-behavior-of-lru-related-flags-on-compound-pages.patch
page-flags-define-behavior-slb-related-flags-on-compound-pages.patch
page-flags-define-behavior-of-xen-related-flags-on-compound-pages.patch
page-flags-define-pg_reserved-behavior-on-compound-pages.patch
page-flags-define-pg_reserved-behavior-on-compound-pages-fix.patch
page-flags-define-pg_swapbacked-behavior-on-compound-pages.patch
page-flags-define-pg_swapcache-behavior-on-compound-pages.patch
page-flags-define-pg_mlocked-behavior-on-compound-pages.patch
page-flags-define-pg_uncached-behavior-on-compound-pages.patch
page-flags-define-pg_uptodate-behavior-on-compound-pages.patch
page-flags-look-at-head-page-if-the-flag-is-encoded-in-page-mapping.patch
mm-sanitize-page-mapping-for-tail-pages.patch
mm-proc-adjust-pss-calculation.patch
rmap-add-argument-to-charge-compound-page.patch
memcg-adjust-to-support-new-thp-refcounting.patch
mm-thp-adjust-conditions-when-we-can-reuse-the-page-on-wp-fault.patch
mm-adjust-foll_split-for-new-refcounting.patch
mm-handle-pte-mapped-tail-pages-in-gerneric-fast-gup-implementaiton.patch
thp-mlock-do-not-allow-huge-pages-in-mlocked-area.patch
khugepaged-ignore-pmd-tables-with-thp-mapped-with-ptes.patch
thp-rename-split_huge_page_pmd-to-split_huge_pmd.patch
mm-vmstats-new-thp-splitting-event.patch
mm-temporally-mark-thp-broken.patch
thp-drop-all-split_huge_page-related-code.patch
mm-drop-tail-page-refcounting.patch
futex-thp-remove-special-case-for-thp-in-get_futex_key.patch
ksm-prepare-to-new-thp-semantics.patch
mm-thp-remove-compound_lock.patch
arm64-thp-remove-infrastructure-for-handling-splitting-pmds.patch
arm-thp-remove-infrastructure-for-handling-splitting-pmds.patch
mips-thp-remove-infrastructure-for-handling-splitting-pmds.patch
powerpc-thp-remove-infrastructure-for-handling-splitting-pmds.patch
s390-thp-remove-infrastructure-for-handling-splitting-pmds.patch
sparc-thp-remove-infrastructure-for-handling-splitting-pmds.patch
tile-thp-remove-infrastructure-for-handling-splitting-pmds.patch
x86-thp-remove-infrastructure-for-handling-splitting-pmds.patch
mm-thp-remove-infrastructure-for-handling-splitting-pmds.patch
mm-rework-mapcount-accounting-to-enable-4k-mapping-of-thps.patch
mm-differentiate-page_mapped-from-page_mapcount-for-compound-pages.patch
mm-numa-skip-pte-mapped-thp-on-numa-fault.patch
thp-implement-split_huge_pmd.patch
thp-add-option-to-setup-migration-entries-during-pmd-split.patch
thp-mm-split_huge_page-caller-need-to-lock-page.patch
thp-reintroduce-split_huge_page.patch
migrate_pages-try-to-split-pages-on-qeueuing.patch
thp-introduce-deferred_split_huge_page.patch
mm-re-enable-thp.patch
thp-update-documentation.patch
thp-allow-mlocked-thp-again.patch
mm-support-madvisemadv_free-fix-3.patch
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