From e1534ae95004d6a307839a44eed40389d608c935 Mon Sep 17 00:00:00 2001 From: "Kirill A. Shutemov" Date: Fri, 15 Jan 2016 16:53:46 -0800 Subject: [PATCH] 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 Tested-by: Sasha Levin Tested-by: Aneesh Kumar K.V Acked-by: Jerome Marchand Cc: Vlastimil Babka Cc: Andrea Arcangeli Cc: Hugh Dickins Cc: Dave Hansen Cc: Mel Gorman Cc: Rik van Riel Cc: Naoya Horiguchi Cc: Steve Capper Cc: Johannes Weiner Cc: Michal Hocko Cc: Christoph Lameter Cc: David Rientjes Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- 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 --git a/arch/arc/mm/cache.c b/arch/arc/mm/cache.c index ff7ff6cbb811..b65f797e9ad6 100644 --- a/arch/arc/mm/cache.c +++ b/arch/arc/mm/cache.c @@ -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; } diff --git a/arch/arm/mm/flush.c b/arch/arm/mm/flush.c index c2acebb7eedc..d0ba3551d49a 100644 --- a/arch/arm/mm/flush.c +++ b/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 --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c index 5d3a25e1cfae..caac3d747a90 100644 --- a/arch/mips/mm/c-r4k.c +++ b/arch/mips/mm/c-r4k.c @@ -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 diff --git a/arch/mips/mm/cache.c b/arch/mips/mm/cache.c index aab218c36e0d..3f159caf6dbc 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 8770e619185e..7e5fa0938c21 100644 --- a/arch/mips/mm/init.c +++ b/arch/mips/mm/init.c @@ -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(); 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 93484034a03d..b2855eea5405 100644 --- a/fs/proc/page.c +++ b/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 --git a/include/linux/mm.h b/include/linux/mm.h index 67e0fab225e8..6b56cfd9fd09 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -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; } /* diff --git a/mm/filemap.c b/mm/filemap.c index a729345ed6ec..847ee43c2806 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -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. -- 2.20.1