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mm: differentiate page_mapped() from page_mapcount() for compound pages

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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@linux.intel.com>
Tested-by: Sasha Levin <sasha.levin@oracle.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Steve Capper <steve.capper@linaro.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Kirill A. Shutemov 2016-01-15 16:53:46 -08:00 committed by Linus Torvalds
parent 53f9263bab
commit e1534ae950
11 changed files with 31 additions and 19 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

4
arch/arc/mm/cache.c
View file

@ -617,7 +617,7 @@ 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 */
phys_addr_t paddr = (unsigned long)page_address(page);
@ -857,7 +857,7 @@ void copy_user_highpage(struct page *to, struct page *from,
* For !VIPT cache, all of this gets compiled out as
* addr_not_cache_congruent() is 0
*/
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((unsigned long)kfrom, u_vaddr);
clean_src_k_mappings = 1;
}

2
arch/arm/mm/flush.c
View file

@ -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);

3
arch/mips/mm/c-r4k.c
View file

@ -587,7 +587,8 @@ static inline void local_r4k_flush_cache_page(void *args)
* 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

2
arch/mips/mm/cache.c
View file

@ -106,7 +106,7 @@ void __flush_anon_page(struct page *page, unsigned long vmaddr)
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);

6
arch/mips/mm/init.c
View file

@ -165,7 +165,7 @@ void copy_user_highpage(struct page *to, struct page *from,
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_struct *vma,
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_struct *vma,
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();

2
arch/sh/mm/cache-sh4.c
View file

@ -241,7 +241,7 @@ static void sh4_flush_cache_page(void *args)
*/
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

8
arch/sh/mm/cache.c
View file

@ -59,7 +59,7 @@ void copy_to_user_page(struct vm_area_struct *vma, struct page *page,
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_struct *vma, struct page *page,
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, struct page *from,
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 vmaddr)
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;

2
arch/xtensa/mm/tlb.c
View file

@ -245,7 +245,7 @@ static int check_tlb_entry(unsigned w, unsigned e, bool dtlb)
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;

4
fs/proc/page.c
View file

@ -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;

15
include/linux/mm.h
View file

@ -953,10 +953,21 @@ static inline pgoff_t page_file_index(struct page *page)
/*
* 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;
}
/*

2
mm/filemap.c
View file

@ -204,7 +204,7 @@ void __delete_from_page_cache(struct page *page, void *shadow,
__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.