From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: [patch 022/166] mm: code cleanup for MADV_FREE Date: Mon, 06 Apr 2020 20:04:41 -0700 Message-ID: <20200407030441.ImU66HuCM%akpm@linux-foundation.org> References: <20200406200254.a69ebd9e08c4074e41ddebaf@linux-foundation.org> Reply-To: linux-kernel@vger.kernel.org Return-path: Received: from mail.kernel.org ([198.145.29.99]:48614 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726637AbgDGDEn (ORCPT ); Mon, 6 Apr 2020 23:04:43 -0400 In-Reply-To: <20200406200254.a69ebd9e08c4074e41ddebaf@linux-foundation.org> Sender: mm-commits-owner@vger.kernel.org List-Id: mm-commits@vger.kernel.org To: akpm@linux-foundation.org, dave.hansen@linux.intel.com, david@redhat.com, hannes@cmpxchg.org, hughd@google.com, linux-mm@kvack.org, mgorman@suse.de, mhocko@kernel.org, minchan@kernel.org, mm-commits@vger.kernel.org, pankaj.gupta.linux@gmail.com, riel@surriel.com, rientjes@google.com, torvalds@linux-foundation.org, vbabka@suse.cz, ying.huang@intel.com From: Huang Ying Subject: mm: code cleanup for MADV_FREE Some comments for MADV_FREE is revised and added to help people understand the MADV_FREE code, especially the page flag, PG_swapbacked. This makes page_is_file_cache() isn't consistent with its comments. So the function is renamed to page_is_file_lru() to make them consistent again. All these are put in one patch as one logical change. Link: http://lkml.kernel.org/r/20200317100342.2730705-1-ying.huang@intel.com Signed-off-by: "Huang, Ying" Suggested-by: David Hildenbrand Suggested-by: Johannes Weiner Acked-by: Johannes Weiner Suggested-by: David Rientjes Acked-by: David Rientjes Acked-by: Michal Hocko Acked-by: Pankaj Gupta Acked-by: Vlastimil Babka Cc: Dave Hansen Cc: Mel Gorman Cc: Minchan Kim Cc: Hugh Dickins Cc: Rik van Riel Signed-off-by: Andrew Morton --- include/linux/mm_inline.h | 15 ++++++++------- include/linux/page-flags.h | 5 +++++ include/trace/events/vmscan.h | 2 +- mm/compaction.c | 2 +- mm/gup.c | 2 +- mm/khugepaged.c | 4 ++-- mm/memory-failure.c | 2 +- mm/memory_hotplug.c | 2 +- mm/mempolicy.c | 2 +- mm/migrate.c | 16 ++++++++-------- mm/mprotect.c | 2 +- mm/swap.c | 16 ++++++++-------- mm/vmscan.c | 12 ++++++------ 13 files changed, 44 insertions(+), 38 deletions(-) --- a/include/linux/mm_inline.h~mm-code-cleanup-for-madv_free +++ a/include/linux/mm_inline.h @@ -6,19 +6,20 @@ #include /** - * page_is_file_cache - should the page be on a file LRU or anon LRU? + * page_is_file_lru - should the page be on a file LRU or anon LRU? * @page: the page to test * - * Returns 1 if @page is page cache page backed by a regular filesystem, - * or 0 if @page is anonymous, tmpfs or otherwise ram or swap backed. - * Used by functions that manipulate the LRU lists, to sort a page - * onto the right LRU list. + * Returns 1 if @page is a regular filesystem backed page cache page or a lazily + * freed anonymous page (e.g. via MADV_FREE). Returns 0 if @page is a normal + * anonymous page, a tmpfs page or otherwise ram or swap backed page. Used by + * functions that manipulate the LRU lists, to sort a page onto the right LRU + * list. * * We would like to get this info without a page flag, but the state * needs to survive until the page is last deleted from the LRU, which * could be as far down as __page_cache_release. */ -static inline int page_is_file_cache(struct page *page) +static inline int page_is_file_lru(struct page *page) { return !PageSwapBacked(page); } @@ -75,7 +76,7 @@ static __always_inline void del_page_fro */ static inline enum lru_list page_lru_base_type(struct page *page) { - if (page_is_file_cache(page)) + if (page_is_file_lru(page)) return LRU_INACTIVE_FILE; return LRU_INACTIVE_ANON; } --- a/include/linux/page-flags.h~mm-code-cleanup-for-madv_free +++ a/include/linux/page-flags.h @@ -63,6 +63,11 @@ * page_waitqueue(page) is a wait queue of all tasks waiting for the page * to become unlocked. * + * PG_swapbacked is set when a page uses swap as a backing storage. This are + * usually PageAnon or shmem pages but please note that even anonymous pages + * might lose their PG_swapbacked flag when they simply can be dropped (e.g. as + * a result of MADV_FREE). + * * PG_uptodate tells whether the page's contents is valid. When a read * completes, the page becomes uptodate, unless a disk I/O error happened. * --- a/include/trace/events/vmscan.h~mm-code-cleanup-for-madv_free +++ a/include/trace/events/vmscan.h @@ -323,7 +323,7 @@ TRACE_EVENT(mm_vmscan_writepage, TP_fast_assign( __entry->pfn = page_to_pfn(page); __entry->reclaim_flags = trace_reclaim_flags( - page_is_file_cache(page)); + page_is_file_lru(page)); ), TP_printk("page=%p pfn=%lu flags=%s", --- a/mm/compaction.c~mm-code-cleanup-for-madv_free +++ a/mm/compaction.c @@ -989,7 +989,7 @@ isolate_migratepages_block(struct compac /* Successfully isolated */ del_page_from_lru_list(page, lruvec, page_lru(page)); mod_node_page_state(page_pgdat(page), - NR_ISOLATED_ANON + page_is_file_cache(page), + NR_ISOLATED_ANON + page_is_file_lru(page), hpage_nr_pages(page)); isolate_success: --- a/mm/gup.c~mm-code-cleanup-for-madv_free +++ a/mm/gup.c @@ -1677,7 +1677,7 @@ check_again: list_add_tail(&head->lru, &cma_page_list); mod_node_page_state(page_pgdat(head), NR_ISOLATED_ANON + - page_is_file_cache(head), + page_is_file_lru(head), hpage_nr_pages(head)); } } --- a/mm/khugepaged.c~mm-code-cleanup-for-madv_free +++ a/mm/khugepaged.c @@ -511,7 +511,7 @@ void __khugepaged_exit(struct mm_struct static void release_pte_page(struct page *page) { - dec_node_page_state(page, NR_ISOLATED_ANON + page_is_file_cache(page)); + dec_node_page_state(page, NR_ISOLATED_ANON + page_is_file_lru(page)); unlock_page(page); putback_lru_page(page); } @@ -611,7 +611,7 @@ static int __collapse_huge_page_isolate( goto out; } inc_node_page_state(page, - NR_ISOLATED_ANON + page_is_file_cache(page)); + NR_ISOLATED_ANON + page_is_file_lru(page)); VM_BUG_ON_PAGE(!PageLocked(page), page); VM_BUG_ON_PAGE(PageLRU(page), page); --- a/mm/memory-failure.c~mm-code-cleanup-for-madv_free +++ a/mm/memory-failure.c @@ -1810,7 +1810,7 @@ static int __soft_offline_page(struct pa */ if (!__PageMovable(page)) inc_node_page_state(page, NR_ISOLATED_ANON + - page_is_file_cache(page)); + page_is_file_lru(page)); list_add(&page->lru, &pagelist); ret = migrate_pages(&pagelist, new_page, NULL, MPOL_MF_MOVE_ALL, MIGRATE_SYNC, MR_MEMORY_FAILURE); --- a/mm/memory_hotplug.c~mm-code-cleanup-for-madv_free +++ a/mm/memory_hotplug.c @@ -1317,7 +1317,7 @@ do_migrate_range(unsigned long start_pfn list_add_tail(&page->lru, &source); if (!__PageMovable(page)) inc_node_page_state(page, NR_ISOLATED_ANON + - page_is_file_cache(page)); + page_is_file_lru(page)); } else { pr_warn("failed to isolate pfn %lx\n", pfn); --- a/mm/mempolicy.c~mm-code-cleanup-for-madv_free +++ a/mm/mempolicy.c @@ -1022,7 +1022,7 @@ static int migrate_page_add(struct page if (!isolate_lru_page(head)) { list_add_tail(&head->lru, pagelist); mod_node_page_state(page_pgdat(head), - NR_ISOLATED_ANON + page_is_file_cache(head), + NR_ISOLATED_ANON + page_is_file_lru(head), hpage_nr_pages(head)); } else if (flags & MPOL_MF_STRICT) { /* --- a/mm/migrate.c~mm-code-cleanup-for-madv_free +++ a/mm/migrate.c @@ -193,7 +193,7 @@ void putback_movable_pages(struct list_h put_page(page); } else { mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + - page_is_file_cache(page), -hpage_nr_pages(page)); + page_is_file_lru(page), -hpage_nr_pages(page)); putback_lru_page(page); } } @@ -1219,7 +1219,7 @@ out: */ if (likely(!__PageMovable(page))) mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + - page_is_file_cache(page), -hpage_nr_pages(page)); + page_is_file_lru(page), -hpage_nr_pages(page)); } /* @@ -1592,7 +1592,7 @@ static int add_page_for_migration(struct err = 1; list_add_tail(&head->lru, pagelist); mod_node_page_state(page_pgdat(head), - NR_ISOLATED_ANON + page_is_file_cache(head), + NR_ISOLATED_ANON + page_is_file_lru(head), hpage_nr_pages(head)); } out_putpage: @@ -1955,7 +1955,7 @@ static int numamigrate_isolate_page(pg_d return 0; } - page_lru = page_is_file_cache(page); + page_lru = page_is_file_lru(page); mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + page_lru, hpage_nr_pages(page)); @@ -1991,7 +1991,7 @@ int migrate_misplaced_page(struct page * * Don't migrate file pages that are mapped in multiple processes * with execute permissions as they are probably shared libraries. */ - if (page_mapcount(page) != 1 && page_is_file_cache(page) && + if (page_mapcount(page) != 1 && page_is_file_lru(page) && (vma->vm_flags & VM_EXEC)) goto out; @@ -1999,7 +1999,7 @@ int migrate_misplaced_page(struct page * * Also do not migrate dirty pages as not all filesystems can move * dirty pages in MIGRATE_ASYNC mode which is a waste of cycles. */ - if (page_is_file_cache(page) && PageDirty(page)) + if (page_is_file_lru(page) && PageDirty(page)) goto out; isolated = numamigrate_isolate_page(pgdat, page); @@ -2014,7 +2014,7 @@ int migrate_misplaced_page(struct page * if (!list_empty(&migratepages)) { list_del(&page->lru); dec_node_page_state(page, NR_ISOLATED_ANON + - page_is_file_cache(page)); + page_is_file_lru(page)); putback_lru_page(page); } isolated = 0; @@ -2044,7 +2044,7 @@ int migrate_misplaced_transhuge_page(str pg_data_t *pgdat = NODE_DATA(node); int isolated = 0; struct page *new_page = NULL; - int page_lru = page_is_file_cache(page); + int page_lru = page_is_file_lru(page); unsigned long start = address & HPAGE_PMD_MASK; new_page = alloc_pages_node(node, --- a/mm/mprotect.c~mm-code-cleanup-for-madv_free +++ a/mm/mprotect.c @@ -98,7 +98,7 @@ static unsigned long change_pte_range(st * it cannot move them all from MIGRATE_ASYNC * context. */ - if (page_is_file_cache(page) && PageDirty(page)) + if (page_is_file_lru(page) && PageDirty(page)) continue; /* --- a/mm/swap.c~mm-code-cleanup-for-madv_free +++ a/mm/swap.c @@ -276,7 +276,7 @@ static void __activate_page(struct page void *arg) { if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { - int file = page_is_file_cache(page); + int file = page_is_file_lru(page); int lru = page_lru_base_type(page); del_page_from_lru_list(page, lruvec, lru); @@ -394,7 +394,7 @@ void mark_page_accessed(struct page *pag else __lru_cache_activate_page(page); ClearPageReferenced(page); - if (page_is_file_cache(page)) + if (page_is_file_lru(page)) workingset_activation(page); } if (page_is_idle(page)) @@ -515,7 +515,7 @@ static void lru_deactivate_file_fn(struc return; active = PageActive(page); - file = page_is_file_cache(page); + file = page_is_file_lru(page); lru = page_lru_base_type(page); del_page_from_lru_list(page, lruvec, lru + active); @@ -548,7 +548,7 @@ static void lru_deactivate_fn(struct pag void *arg) { if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) { - int file = page_is_file_cache(page); + int file = page_is_file_lru(page); int lru = page_lru_base_type(page); del_page_from_lru_list(page, lruvec, lru + LRU_ACTIVE); @@ -573,9 +573,9 @@ static void lru_lazyfree_fn(struct page ClearPageActive(page); ClearPageReferenced(page); /* - * lazyfree pages are clean anonymous pages. They have - * SwapBacked flag cleared to distinguish normal anonymous - * pages + * Lazyfree pages are clean anonymous pages. They have + * PG_swapbacked flag cleared, to distinguish them from normal + * anonymous pages */ ClearPageSwapBacked(page); add_page_to_lru_list(page, lruvec, LRU_INACTIVE_FILE); @@ -962,7 +962,7 @@ static void __pagevec_lru_add_fn(struct if (page_evictable(page)) { lru = page_lru(page); - update_page_reclaim_stat(lruvec, page_is_file_cache(page), + update_page_reclaim_stat(lruvec, page_is_file_lru(page), PageActive(page)); if (was_unevictable) count_vm_event(UNEVICTABLE_PGRESCUED); --- a/mm/vmscan.c~mm-code-cleanup-for-madv_free +++ a/mm/vmscan.c @@ -919,7 +919,7 @@ static int __remove_mapping(struct addre * exceptional entries and shadow exceptional entries in the * same address_space. */ - if (reclaimed && page_is_file_cache(page) && + if (reclaimed && page_is_file_lru(page) && !mapping_exiting(mapping) && !dax_mapping(mapping)) shadow = workingset_eviction(page, target_memcg); __delete_from_page_cache(page, shadow); @@ -1043,7 +1043,7 @@ static void page_check_dirty_writeback(s * Anonymous pages are not handled by flushers and must be written * from reclaim context. Do not stall reclaim based on them */ - if (!page_is_file_cache(page) || + if (!page_is_file_lru(page) || (PageAnon(page) && !PageSwapBacked(page))) { *dirty = false; *writeback = false; @@ -1315,7 +1315,7 @@ static unsigned long shrink_page_list(st * the rest of the LRU for clean pages and see * the same dirty pages again (PageReclaim). */ - if (page_is_file_cache(page) && + if (page_is_file_lru(page) && (!current_is_kswapd() || !PageReclaim(page) || !test_bit(PGDAT_DIRTY, &pgdat->flags))) { /* @@ -1459,7 +1459,7 @@ activate_locked: try_to_free_swap(page); VM_BUG_ON_PAGE(PageActive(page), page); if (!PageMlocked(page)) { - int type = page_is_file_cache(page); + int type = page_is_file_lru(page); SetPageActive(page); stat->nr_activate[type] += nr_pages; count_memcg_page_event(page, PGACTIVATE); @@ -1497,7 +1497,7 @@ unsigned long reclaim_clean_pages_from_l LIST_HEAD(clean_pages); list_for_each_entry_safe(page, next, page_list, lru) { - if (page_is_file_cache(page) && !PageDirty(page) && + if (page_is_file_lru(page) && !PageDirty(page) && !__PageMovable(page) && !PageUnevictable(page)) { ClearPageActive(page); list_move(&page->lru, &clean_pages); @@ -2053,7 +2053,7 @@ static void shrink_active_list(unsigned * IO, plus JVM can create lots of anon VM_EXEC pages, * so we ignore them here. */ - if ((vm_flags & VM_EXEC) && page_is_file_cache(page)) { + if ((vm_flags & VM_EXEC) && page_is_file_lru(page)) { list_add(&page->lru, &l_active); continue; } _