On Wed, Apr 29, 2015 at 06:20:03PM +0200, Jerome Marchand wrote: > On 04/23/2015 11:03 PM, Kirill A. Shutemov wrote: > > 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 <[email protected]> > > Tested-by: Sasha Levin <[email protected]> > > --- > > arch/arc/mm/cache_arc700.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 | 11 ++++++++++- > > mm/filemap.c | 2 +- > > 11 files changed, 28 insertions(+), 18 deletions(-) > > > > diff --git a/arch/arc/mm/cache_arc700.c b/arch/arc/mm/cache_arc700.c > > index 8c3a3e02ba92..1baa4d23314b 100644 > > --- a/arch/arc/mm/cache_arc700.c > > +++ b/arch/arc/mm/cache_arc700.c > > @@ -490,7 +490,7 @@ 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 */ > > void *paddr = page_address(page); > > @@ -675,7 +675,7 @@ void copy_user_highpage(struct page *to, struct page > > *from, > > * 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 --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c > > index 34b66af516ea..8f972fc8933d 100644 > > --- a/arch/arm/mm/flush.c > > +++ b/arch/arm/mm/flush.c > > @@ -315,7 +315,7 @@ 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 --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c > > index dd261df005c2..c4960b2d6682 100644 > > --- a/arch/mips/mm/c-r4k.c > > +++ b/arch/mips/mm/c-r4k.c > > @@ -578,7 +578,8 @@ 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 > > diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c > > index 7e3ea7766822..e695b28dc32c 100644 > > --- a/arch/mips/mm/cache.c > > +++ b/arch/mips/mm/cache.c > > @@ -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); > > diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c > > index 448cde372af0..2c8e44aa536e 100644 > > --- a/arch/mips/mm/init.c > > +++ b/arch/mips/mm/init.c > > @@ -156,7 +156,7 @@ 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(); > > @@ -178,7 +178,7 @@ 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(); > > @@ -196,7 +196,7 @@ 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(); > > diff --git a/arch/sh/mm/cache-sh4.c b/arch/sh/mm/cache-sh4.c > > index 51d8f7f31d1d..58aaa4f33b81 100644 > > --- a/arch/sh/mm/cache-sh4.c > > +++ b/arch/sh/mm/cache-sh4.c > > @@ -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 > > diff --git a/arch/sh/mm/cache.c b/arch/sh/mm/cache.c > > index f770e3992620..e58cfbf45150 100644 > > --- a/arch/sh/mm/cache.c > > +++ b/arch/sh/mm/cache.c > > @@ -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; > > > > diff --git a/arch/xtensa/mm/tlb.c b/arch/xtensa/mm/tlb.c > > index 5ece856c5725..35c822286bbe 100644 > > --- a/arch/xtensa/mm/tlb.c > > +++ b/arch/xtensa/mm/tlb.c > > @@ -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; > > diff --git a/fs/proc/page.c b/fs/proc/page.c > > index 7eee2d8b97d9..e99c059339f6 100644 > > --- a/fs/proc/page.c > > +++ b/fs/proc/page.c > > @@ -97,9 +97,9 @@ 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 --git a/include/linux/mm.h b/include/linux/mm.h > > index 33cb3aa647a6..8ddc184c55d6 100644 > > --- a/include/linux/mm.h > > +++ b/include/linux/mm.h > > @@ -909,7 +909,16 @@ static inline pgoff_t page_file_index(struct page > > *page) > > */ > > static inline int 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; > > + if (compound_mapcount(page)) > > + return 1; > > + for (i = 0; i < hpage_nr_pages(page); i++) { > > + if (atomic_read(&page[i]._mapcount) >= 0) > > + return 1; > > + } > > + return 0; > > } > > page_mapped() won't work with tail pages. Maybe I'm missing something > that makes it impossible. Otherwise, have you checked that this > condition is true for all call site? Should we add some check at the > beginning of the function? Something like: > > VM_BUG_ON_PAGE(PageTail(page), page)?
Good catch. I will probably put compound_head() there. Thanks. -- Kirill A. Shutemov -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
