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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@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>
hifive-unleashed-5.1
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
Show 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.