From: Kirill A. Shutemov Date: Tue, 26 Jul 2016 22:25:26 +0000 (-0700) Subject: rmap: support file thp X-Git-Url: http://git.cdn.openwrt.org/?a=commitdiff_plain;h=dd78fedde4b99b322f2dc849d467d365a82e23ca;p=openwrt%2Fstaging%2Fblogic.git rmap: support file thp Naive approach: on mapping/unmapping the page as compound we update ->_mapcount on each 4k page. That's not efficient, but it's not obvious how we can optimize this. We can look into optimization later. PG_double_map optimization doesn't work for file pages since lifecycle of file pages is different comparing to anon pages: file page can be mapped again at any time. Link: http://lkml.kernel.org/r/1466021202-61880-11-git-send-email-kirill.shutemov@linux.intel.com Signed-off-by: Kirill A. Shutemov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 2b0fad83683f..b46bb5620a76 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -165,7 +165,7 @@ void do_page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long, int); void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long, bool); -void page_add_file_rmap(struct page *); +void page_add_file_rmap(struct page *, bool); void page_remove_rmap(struct page *, bool); void hugepage_add_anon_rmap(struct page *, struct vm_area_struct *, diff --git a/mm/huge_memory.c b/mm/huge_memory.c index bc5abcbe376e..90f5dd22b1c8 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3301,18 +3301,22 @@ static void __split_huge_page(struct page *page, struct list_head *list) int total_mapcount(struct page *page) { - int i, ret; + int i, compound, ret; VM_BUG_ON_PAGE(PageTail(page), page); if (likely(!PageCompound(page))) return atomic_read(&page->_mapcount) + 1; - ret = compound_mapcount(page); + compound = compound_mapcount(page); if (PageHuge(page)) - return ret; + return compound; + ret = compound; for (i = 0; i < HPAGE_PMD_NR; i++) ret += atomic_read(&page[i]._mapcount) + 1; + /* File pages has compound_mapcount included in _mapcount */ + if (!PageAnon(page)) + return ret - compound * HPAGE_PMD_NR; if (PageDoubleMap(page)) ret -= HPAGE_PMD_NR; return ret; diff --git a/mm/memory.c b/mm/memory.c index 1991105bf67c..30cda24ff205 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1494,7 +1494,7 @@ static int insert_page(struct vm_area_struct *vma, unsigned long addr, /* Ok, finally just insert the thing.. */ get_page(page); inc_mm_counter_fast(mm, mm_counter_file(page)); - page_add_file_rmap(page); + page_add_file_rmap(page, false); set_pte_at(mm, addr, pte, mk_pte(page, prot)); retval = 0; @@ -2962,7 +2962,7 @@ int alloc_set_pte(struct fault_env *fe, struct mem_cgroup *memcg, lru_cache_add_active_or_unevictable(page, vma); } else { inc_mm_counter_fast(vma->vm_mm, mm_counter_file(page)); - page_add_file_rmap(page); + page_add_file_rmap(page, false); } set_pte_at(vma->vm_mm, fe->address, fe->pte, entry); diff --git a/mm/migrate.c b/mm/migrate.c index f278005f609c..e85a72c0d6f0 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -259,7 +259,7 @@ static int remove_migration_pte(struct page *new, struct vm_area_struct *vma, } else if (PageAnon(new)) page_add_anon_rmap(new, vma, addr, false); else - page_add_file_rmap(new); + page_add_file_rmap(new, false); if (vma->vm_flags & VM_LOCKED && !PageTransCompound(new)) mlock_vma_page(new); diff --git a/mm/rmap.c b/mm/rmap.c index 701b93fea2a0..2b336c4277da 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1270,18 +1270,34 @@ void page_add_new_anon_rmap(struct page *page, * * The caller needs to hold the pte lock. */ -void page_add_file_rmap(struct page *page) +void page_add_file_rmap(struct page *page, bool compound) { + int i, nr = 1; + + VM_BUG_ON_PAGE(compound && !PageTransHuge(page), page); lock_page_memcg(page); - if (atomic_inc_and_test(&page->_mapcount)) { - __inc_zone_page_state(page, NR_FILE_MAPPED); - mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED); + if (compound && PageTransHuge(page)) { + for (i = 0, nr = 0; i < HPAGE_PMD_NR; i++) { + if (atomic_inc_and_test(&page[i]._mapcount)) + nr++; + } + if (!atomic_inc_and_test(compound_mapcount_ptr(page))) + goto out; + } else { + if (!atomic_inc_and_test(&page->_mapcount)) + goto out; } + __mod_zone_page_state(page_zone(page), NR_FILE_MAPPED, nr); + mem_cgroup_inc_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED); +out: unlock_page_memcg(page); } -static void page_remove_file_rmap(struct page *page) +static void page_remove_file_rmap(struct page *page, bool compound) { + int i, nr = 1; + + VM_BUG_ON_PAGE(compound && !PageTransHuge(page), page); lock_page_memcg(page); /* Hugepages are not counted in NR_FILE_MAPPED for now. */ @@ -1292,15 +1308,24 @@ static void page_remove_file_rmap(struct page *page) } /* page still mapped by someone else? */ - if (!atomic_add_negative(-1, &page->_mapcount)) - goto out; + if (compound && PageTransHuge(page)) { + for (i = 0, nr = 0; i < HPAGE_PMD_NR; i++) { + if (atomic_add_negative(-1, &page[i]._mapcount)) + nr++; + } + if (!atomic_add_negative(-1, compound_mapcount_ptr(page))) + goto out; + } else { + if (!atomic_add_negative(-1, &page->_mapcount)) + goto out; + } /* * We use the irq-unsafe __{inc|mod}_zone_page_stat because * these counters are not modified in interrupt context, and * pte lock(a spinlock) is held, which implies preemption disabled. */ - __dec_zone_page_state(page, NR_FILE_MAPPED); + __mod_zone_page_state(page_zone(page), NR_FILE_MAPPED, -nr); mem_cgroup_dec_page_stat(page, MEM_CGROUP_STAT_FILE_MAPPED); if (unlikely(PageMlocked(page))) @@ -1356,11 +1381,8 @@ static void page_remove_anon_compound_rmap(struct page *page) */ void page_remove_rmap(struct page *page, bool compound) { - if (!PageAnon(page)) { - VM_BUG_ON_PAGE(compound && !PageHuge(page), page); - page_remove_file_rmap(page); - return; - } + if (!PageAnon(page)) + return page_remove_file_rmap(page, compound); if (compound) return page_remove_anon_compound_rmap(page); diff --git a/mm/util.c b/mm/util.c index b756ee36f7f0..8d010ef2ce1c 100644 --- a/mm/util.c +++ b/mm/util.c @@ -412,6 +412,12 @@ int __page_mapcount(struct page *page) int ret; ret = atomic_read(&page->_mapcount) + 1; + /* + * For file THP page->_mapcount contains total number of mapping + * of the page: no need to look into compound_mapcount. + */ + if (!PageAnon(page) && !PageHuge(page)) + return ret; page = compound_head(page); ret += atomic_read(compound_mapcount_ptr(page)) + 1; if (PageDoubleMap(page))