From bc53008eea55330f485c956338d3c59f96c70c08 Mon Sep 17 00:00:00 2001 From: Wei Yang Date: Thu, 28 Apr 2022 23:16:03 -0700 Subject: mm/vmscan: make sure wakeup_kswapd with managed zone wakeup_kswapd() only wake up kswapd when the zone is managed. For two callers of wakeup_kswapd(), they are node perspective. * wake_all_kswapds * numamigrate_isolate_page If we picked up a !managed zone, this is not we expected. This patch makes sure we pick up a managed zone for wakeup_kswapd(). And it also use managed_zone in migrate_balanced_pgdat() to get the proper zone. [richard.weiyang@gmail.com: adjust the usage in migrate_balanced_pgdat()] Link: https://lkml.kernel.org/r/20220329010901.1654-2-richard.weiyang@gmail.com Link: https://lkml.kernel.org/r/20220327024101.10378-2-richard.weiyang@gmail.com Signed-off-by: Wei Yang Reviewed-by: "Huang, Ying" Reviewed-by: Miaohe Lin Reviewed-by: David Hildenbrand Cc: Mel Gorman Cc: Oscar Salvador Signed-off-by: Andrew Morton --- mm/migrate.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 6c31ee1e1c9b..d298544940b8 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1969,7 +1969,7 @@ SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages, #ifdef CONFIG_NUMA_BALANCING /* * Returns true if this is a safe migration target node for misplaced NUMA - * pages. Currently it only checks the watermarks which crude + * pages. Currently it only checks the watermarks which is crude. */ static bool migrate_balanced_pgdat(struct pglist_data *pgdat, unsigned long nr_migrate_pages) @@ -1979,7 +1979,7 @@ static bool migrate_balanced_pgdat(struct pglist_data *pgdat, for (z = pgdat->nr_zones - 1; z >= 0; z--) { struct zone *zone = pgdat->node_zones + z; - if (!populated_zone(zone)) + if (!managed_zone(zone)) continue; /* Avoid waking kswapd by allocating pages_to_migrate pages. */ @@ -2032,7 +2032,7 @@ static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page) if (!(sysctl_numa_balancing_mode & NUMA_BALANCING_MEMORY_TIERING)) return 0; for (z = pgdat->nr_zones - 1; z >= 0; z--) { - if (populated_zone(pgdat->node_zones + z)) + if (managed_zone(pgdat->node_zones + z)) break; } wakeup_kswapd(pgdat->node_zones + z, 0, order, ZONE_MOVABLE); -- cgit v1.2.3-58-ga151 From 5202978b48786703a6cec94596067b3fafd1f734 Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Thu, 28 Apr 2022 23:16:07 -0700 Subject: mm/migration: remove unneeded local variable mapping_locked Patch series "A few cleanup and fixup patches for migration", v2. This series contains a few patches to remove unneeded variables, jump label and use helper to simplify the code. Also we fix some bugs such as page refcounts leak , invalid node access and so on. More details can be found in the respective changelogs. This patch (of 11): When mapping_locked is true, TTU_RMAP_LOCKED is always set to ttu. We can check ttu instead so mapping_locked can be removed. And ttu is either 0 or TTU_RMAP_LOCKED now. Change '|=' to '=' to reflect this. Link: https://lkml.kernel.org/r/20220318111709.60311-1-linmiaohe@huawei.com Link: https://lkml.kernel.org/r/20220318111709.60311-2-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Reviewed-by: Muchun Song Cc: Zi Yan Cc: Baolin Wang Cc: "Huang, Ying" Cc: Muchun Song Cc: Alistair Popple Signed-off-by: Andrew Morton --- mm/migrate.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index d298544940b8..7d698caf333f 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1230,7 +1230,6 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, goto put_anon; if (page_mapped(hpage)) { - bool mapping_locked = false; enum ttu_flags ttu = 0; if (!PageAnon(hpage)) { @@ -1244,14 +1243,13 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, if (unlikely(!mapping)) goto unlock_put_anon; - mapping_locked = true; - ttu |= TTU_RMAP_LOCKED; + ttu = TTU_RMAP_LOCKED; } try_to_migrate(src, ttu); page_was_mapped = 1; - if (mapping_locked) + if (ttu & TTU_RMAP_LOCKED) i_mmap_unlock_write(mapping); } -- cgit v1.2.3-58-ga151 From b75454e10101af3a11b24ca7e14917b6c8874688 Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Thu, 28 Apr 2022 23:16:07 -0700 Subject: mm/migration: remove unneeded local variable page_lru We can use page_is_file_lru() directly to help account the isolated pages to simplify the code a bit. Link: https://lkml.kernel.org/r/20220318111709.60311-4-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Cc: Alistair Popple Cc: Baolin Wang Cc: "Huang, Ying" Cc: Muchun Song Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/migrate.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 7d698caf333f..a993053cd620 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2013,7 +2013,6 @@ static struct page *alloc_misplaced_dst_page(struct page *page, static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page) { - int page_lru; int nr_pages = thp_nr_pages(page); int order = compound_order(page); @@ -2040,8 +2039,7 @@ static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page) if (isolate_lru_page(page)) return 0; - page_lru = page_is_file_lru(page); - mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + page_lru, + mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + page_is_file_lru(page), nr_pages); /* -- cgit v1.2.3-58-ga151 From cb1c37b1c65d9e5450af2ea6ec8916c5cd23a2e7 Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Thu, 28 Apr 2022 23:16:07 -0700 Subject: mm/migration: use helper function vma_lookup() in add_page_for_migration We could use helper function vma_lookup() to lookup the needed vma to simplify the code. Link: https://lkml.kernel.org/r/20220318111709.60311-6-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Cc: Alistair Popple Cc: Baolin Wang Cc: "Huang, Ying" Cc: Muchun Song Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/migrate.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index a993053cd620..e73e1bfa874b 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1604,8 +1604,8 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr, mmap_read_lock(mm); err = -EFAULT; - vma = find_vma(mm, addr); - if (!vma || addr < vma->vm_start || !vma_migratable(vma)) + vma = vma_lookup(mm, addr); + if (!vma || !vma_migratable(vma)) goto out; /* FOLL_DUMP to ignore special (like zero) pages */ -- cgit v1.2.3-58-ga151 From 3eefb826c5a627084eccec788f0236a070988dae Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Thu, 28 Apr 2022 23:16:07 -0700 Subject: mm/migration: use helper macro min in do_pages_stat We could use helper macro min to help set the chunk_nr to simplify the code. Link: https://lkml.kernel.org/r/20220318111709.60311-7-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Reviewed-by: Muchun Song Cc: Alistair Popple Cc: Baolin Wang Cc: "Huang, Ying" Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/migrate.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index e73e1bfa874b..02448b618c6b 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1842,16 +1842,12 @@ static int do_pages_stat(struct mm_struct *mm, unsigned long nr_pages, const void __user * __user *pages, int __user *status) { -#define DO_PAGES_STAT_CHUNK_NR 16 +#define DO_PAGES_STAT_CHUNK_NR 16UL const void __user *chunk_pages[DO_PAGES_STAT_CHUNK_NR]; int chunk_status[DO_PAGES_STAT_CHUNK_NR]; while (nr_pages) { - unsigned long chunk_nr; - - chunk_nr = nr_pages; - if (chunk_nr > DO_PAGES_STAT_CHUNK_NR) - chunk_nr = DO_PAGES_STAT_CHUNK_NR; + unsigned long chunk_nr = min(nr_pages, DO_PAGES_STAT_CHUNK_NR); if (in_compat_syscall()) { if (get_compat_pages_array(chunk_pages, pages, -- cgit v1.2.3-58-ga151 From 91925ab8cc2a05ab0e524830247e1d66ba4e4e19 Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Thu, 28 Apr 2022 23:16:08 -0700 Subject: mm/migration: avoid unneeded nodemask_t initialization Avoid unneeded next_pass and this_pass initialization as they're always set before using to save possible cpu cycles when there are plenty of nodes in the system. Link: https://lkml.kernel.org/r/20220318111709.60311-8-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Reviewed-by: Muchun Song Reviewed-by: Baolin Wang Cc: Alistair Popple Cc: "Huang, Ying" Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/migrate.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 02448b618c6b..d9f378b623ea 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2345,8 +2345,8 @@ out_clear: */ static void __set_migration_target_nodes(void) { - nodemask_t next_pass = NODE_MASK_NONE; - nodemask_t this_pass = NODE_MASK_NONE; + nodemask_t next_pass; + nodemask_t this_pass; nodemask_t used_targets = NODE_MASK_NONE; int node, best_distance; -- cgit v1.2.3-58-ga151 From f430893b01e78e0b2e21f9bd1633a778c063993e Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Thu, 28 Apr 2022 23:16:08 -0700 Subject: mm/migration: remove some duplicated codes in migrate_pages Remove the duplicated codes in migrate_pages to simplify the code. Minor readability improvement. No functional change intended. Link: https://lkml.kernel.org/r/20220318111709.60311-9-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Reviewed-by: Zi Yan Reviewed-by: Baolin Wang Cc: Alistair Popple Cc: "Huang, Ying" Cc: Muchun Song Signed-off-by: Andrew Morton --- mm/migrate.c | 36 ++++++++++++------------------------ 1 file changed, 12 insertions(+), 24 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index d9f378b623ea..161a21314210 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1410,14 +1410,11 @@ retry: nr_thp_split++; goto retry; } - - nr_failed_pages += nr_subpages; - break; - } - /* Hugetlb migration is unsupported */ - if (!no_subpage_counting) + } else if (!no_subpage_counting) { nr_failed++; + } + nr_failed_pages += nr_subpages; break; case -ENOMEM: @@ -1432,28 +1429,22 @@ retry: nr_thp_split++; goto retry; } - - nr_failed_pages += nr_subpages; - goto out; + } else if (!no_subpage_counting) { + nr_failed++; } - if (!no_subpage_counting) - nr_failed++; nr_failed_pages += nr_subpages; goto out; case -EAGAIN: - if (is_thp) { + if (is_thp) thp_retry++; - break; - } - retry++; + else + retry++; break; case MIGRATEPAGE_SUCCESS: nr_succeeded += nr_subpages; - if (is_thp) { + if (is_thp) nr_thp_succeeded++; - break; - } break; default: /* @@ -1462,14 +1453,11 @@ retry: * removed from migration page list and not * retried in the next outer loop. */ - if (is_thp) { + if (is_thp) nr_thp_failed++; - nr_failed_pages += nr_subpages; - break; - } - - if (!no_subpage_counting) + else if (!no_subpage_counting) nr_failed++; + nr_failed_pages += nr_subpages; break; } -- cgit v1.2.3-58-ga151 From 69a041ff505806c95b24b8d5cab43e66aacd91e6 Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Thu, 28 Apr 2022 23:16:08 -0700 Subject: mm/migration: fix potential page refcounts leak in migrate_pages In -ENOMEM case, there might be some subpages of fail-to-migrate THPs left in thp_split_pages list. We should move them back to migration list so that they could be put back to the right list by the caller otherwise the page refcnt will be leaked here. Also adjust nr_failed and nr_thp_failed accordingly to make vm events account more accurate. Link: https://lkml.kernel.org/r/20220318111709.60311-10-linmiaohe@huawei.com Fixes: b5bade978e9b ("mm: migrate: fix the return value of migrate_pages()") Signed-off-by: Miaohe Lin Reviewed-by: Zi Yan Reviewed-by: "Huang, Ying" Reviewed-by: Baolin Wang Reviewed-by: Muchun Song Cc: Alistair Popple Signed-off-by: Andrew Morton --- mm/migrate.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 161a21314210..173ba0507049 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1434,6 +1434,14 @@ retry: } nr_failed_pages += nr_subpages; + /* + * There might be some subpages of fail-to-migrate THPs + * left in thp_split_pages list. Move them back to migration + * list so that they could be put back to the right list by + * the caller otherwise the page refcnt will be leaked. + */ + list_splice_init(&thp_split_pages, from); + nr_thp_failed += thp_retry; goto out; case -EAGAIN: if (is_thp) -- cgit v1.2.3-58-ga151 From 3f26c88bd66cd8ab1731763c68df7fe23a7671c0 Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Thu, 28 Apr 2022 23:16:08 -0700 Subject: mm/migration: fix potential invalid node access for reclaim-based migration If we failed to setup hotplug state callbacks for mm/demotion:online in some corner cases, node_demotion will be left uninitialized. Invalid node might be returned from the next_demotion_node() when doing reclaim-based migration. Use kcalloc to allocate node_demotion to fix the issue. Link: https://lkml.kernel.org/r/20220318111709.60311-11-linmiaohe@huawei.com Fixes: ac16ec835314 ("mm: migrate: support multiple target nodes demotion") Signed-off-by: Miaohe Lin Reviewed-by: "Huang, Ying" Cc: Alistair Popple Cc: Baolin Wang Cc: Muchun Song Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/migrate.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 173ba0507049..cb3fa7c24081 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2479,9 +2479,9 @@ static int __meminit migrate_on_reclaim_callback(struct notifier_block *self, void __init migrate_on_reclaim_init(void) { - node_demotion = kmalloc_array(nr_node_ids, - sizeof(struct demotion_nodes), - GFP_KERNEL); + node_demotion = kcalloc(nr_node_ids, + sizeof(struct demotion_nodes), + GFP_KERNEL); WARN_ON(!node_demotion); hotplug_memory_notifier(migrate_on_reclaim_callback, 100); -- cgit v1.2.3-58-ga151 From 4cd614841c06338a087769ee3cfa96718784d1f5 Mon Sep 17 00:00:00 2001 From: Miaohe Lin Date: Thu, 28 Apr 2022 23:16:08 -0700 Subject: mm/migration: fix possible do_pages_stat_array racing with memory offline When follow_page peeks a page, the page could be migrated and then be offlined while it's still being used by the do_pages_stat_array(). Use FOLL_GET to hold the page refcnt to fix this potential race. Link: https://lkml.kernel.org/r/20220318111709.60311-12-linmiaohe@huawei.com Signed-off-by: Miaohe Lin Acked-by: "Huang, Ying" Reviewed-by: Muchun Song Cc: Alistair Popple Cc: Baolin Wang Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/migrate.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index cb3fa7c24081..35f6416d2953 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1796,13 +1796,18 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, goto set_status; /* FOLL_DUMP to ignore special (like zero) pages */ - page = follow_page(vma, addr, FOLL_DUMP); + page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); err = PTR_ERR(page); if (IS_ERR(page)) goto set_status; - err = page ? page_to_nid(page) : -ENOENT; + if (page) { + err = page_to_nid(page); + put_page(page); + } else { + err = -ENOENT; + } set_status: *status = err; -- cgit v1.2.3-58-ga151 From 9c42fe4e30a9b934b1de66c2edca196563221392 Mon Sep 17 00:00:00 2001 From: Baolin Wang Date: Thu, 28 Apr 2022 23:16:09 -0700 Subject: mm: migrate: simplify the refcount validation when migrating hugetlb mapping There is no need to validate the hugetlb page's refcount before trying to freeze the hugetlb page's expected refcount, instead we can just rely on the page_ref_freeze() to simplify the validation. Moreover we are always under the page lock when migrating the hugetlb page mapping, which means nowhere else can remove it from the page cache, so we can remove the xas_load() validation under the i_pages lock. Link: https://lkml.kernel.org/r/eb2fbbeaef2b1714097b9dec457426d682ee0635.1649676424.git.baolin.wang@linux.alibaba.com Signed-off-by: Baolin Wang Acked-by: Mike Kravetz Cc: Matthew Wilcox Cc: "Huang, Ying" Cc: Muchun Song Cc: Alistair Popple Cc: Zi Yan Signed-off-by: Andrew Morton --- mm/migrate.c | 5 ----- 1 file changed, 5 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index 35f6416d2953..f97d724b8fc0 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -471,11 +471,6 @@ int migrate_huge_page_move_mapping(struct address_space *mapping, xas_lock_irq(&xas); expected_count = 2 + page_has_private(page); - if (page_count(page) != expected_count || xas_load(&xas) != page) { - xas_unlock_irq(&xas); - return -EAGAIN; - } - if (!page_ref_freeze(page, expected_count)) { xas_unlock_irq(&xas); return -EAGAIN; -- cgit v1.2.3-58-ga151 From 7d6e2d96384556a4f30547803be1f606eb805a62 Mon Sep 17 00:00:00 2001 From: Oscar Salvador Date: Thu, 28 Apr 2022 23:16:09 -0700 Subject: mm: untangle config dependencies for demote-on-reclaim At the time demote-on-reclaim was introduced, it was tied to CONFIG_HOTPLUG_CPU + CONFIG_MIGRATE, but that is not really accurate. The only two things we need to depend on are CONFIG_NUMA + CONFIG_MIGRATE, so clean this up. Furthermore, we only register the hotplug memory notifier when the system has CONFIG_MEMORY_HOTPLUG. Link: https://lkml.kernel.org/r/20220322224016.4574-1-osalvador@suse.de Signed-off-by: Oscar Salvador Suggested-by: "Huang, Ying" Reviewed-by: "Huang, Ying" Cc: Dave Hansen Cc: Abhishek Goel Cc: Baolin Wang Signed-off-by: Andrew Morton --- include/linux/migrate.h | 34 +++++++++++++++------------------- mm/migrate.c | 11 ++++++----- mm/vmstat.c | 2 -- 3 files changed, 21 insertions(+), 26 deletions(-) (limited to 'mm/migrate.c') diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 90e75d5a54d6..2707bfd43a0d 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -47,17 +47,8 @@ void folio_migrate_copy(struct folio *newfolio, struct folio *folio); int folio_migrate_mapping(struct address_space *mapping, struct folio *newfolio, struct folio *folio, int extra_count); -extern bool numa_demotion_enabled; -extern void migrate_on_reclaim_init(void); -#ifdef CONFIG_HOTPLUG_CPU -extern void set_migration_target_nodes(void); -#else -static inline void set_migration_target_nodes(void) {} -#endif #else -static inline void set_migration_target_nodes(void) {} - static inline void putback_movable_pages(struct list_head *l) {} static inline int migrate_pages(struct list_head *l, new_page_t new, free_page_t free, unsigned long private, enum migrate_mode mode, @@ -82,9 +73,23 @@ static inline int migrate_huge_page_move_mapping(struct address_space *mapping, return -ENOSYS; } -#define numa_demotion_enabled false #endif /* CONFIG_MIGRATION */ +#if defined(CONFIG_MIGRATION) && defined(CONFIG_NUMA) +extern void set_migration_target_nodes(void); +extern void migrate_on_reclaim_init(void); +extern bool numa_demotion_enabled; +extern int next_demotion_node(int node); +#else +static inline void set_migration_target_nodes(void) {} +static inline void migrate_on_reclaim_init(void) {} +static inline int next_demotion_node(int node) +{ + return NUMA_NO_NODE; +} +#define numa_demotion_enabled false +#endif + #ifdef CONFIG_COMPACTION extern int PageMovable(struct page *page); extern void __SetPageMovable(struct page *page, struct address_space *mapping); @@ -172,15 +177,6 @@ struct migrate_vma { int migrate_vma_setup(struct migrate_vma *args); void migrate_vma_pages(struct migrate_vma *migrate); void migrate_vma_finalize(struct migrate_vma *migrate); -int next_demotion_node(int node); - -#else /* CONFIG_MIGRATION disabled: */ - -static inline int next_demotion_node(int node) -{ - return NUMA_NO_NODE; -} - #endif /* CONFIG_MIGRATION */ #endif /* _LINUX_MIGRATE_H */ diff --git a/mm/migrate.c b/mm/migrate.c index f97d724b8fc0..77592288fbc0 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2104,7 +2104,6 @@ out: return 0; } #endif /* CONFIG_NUMA_BALANCING */ -#endif /* CONFIG_NUMA */ /* * node_demotion[] example: @@ -2238,7 +2237,6 @@ out: return target; } -#if defined(CONFIG_HOTPLUG_CPU) /* Disable reclaim-based migration. */ static void __disable_all_migrate_targets(void) { @@ -2431,6 +2429,7 @@ void set_migration_target_nodes(void) * __set_migration_target_nodes() can be used as opposed to * set_migration_target_nodes(). */ +#ifdef CONFIG_MEMORY_HOTPLUG static int __meminit migrate_on_reclaim_callback(struct notifier_block *self, unsigned long action, void *_arg) { @@ -2476,6 +2475,7 @@ static int __meminit migrate_on_reclaim_callback(struct notifier_block *self, return notifier_from_errno(0); } +#endif void __init migrate_on_reclaim_init(void) { @@ -2483,8 +2483,9 @@ void __init migrate_on_reclaim_init(void) sizeof(struct demotion_nodes), GFP_KERNEL); WARN_ON(!node_demotion); - +#ifdef CONFIG_MEMORY_HOTPLUG hotplug_memory_notifier(migrate_on_reclaim_callback, 100); +#endif /* * At this point, all numa nodes with memory/CPus have their state * properly set, so we can build the demotion order now. @@ -2495,7 +2496,6 @@ void __init migrate_on_reclaim_init(void) set_migration_target_nodes(); cpus_read_unlock(); } -#endif /* CONFIG_HOTPLUG_CPU */ bool numa_demotion_enabled = false; @@ -2556,4 +2556,5 @@ delete_obj: return err; } subsys_initcall(numa_init_sysfs); -#endif +#endif /* CONFIG_SYSFS */ +#endif /* CONFIG_NUMA */ diff --git a/mm/vmstat.c b/mm/vmstat.c index b75b1a64b54c..f2d0dec1062d 100644 --- a/mm/vmstat.c +++ b/mm/vmstat.c @@ -2111,9 +2111,7 @@ void __init init_mm_internals(void) start_shepherd_timer(); #endif -#if defined(CONFIG_MIGRATION) && defined(CONFIG_HOTPLUG_CPU) migrate_on_reclaim_init(); -#endif #ifdef CONFIG_PROC_FS proc_create_seq("buddyinfo", 0444, NULL, &fragmentation_op); proc_create_seq("pagetypeinfo", 0400, NULL, &pagetypeinfo_op); -- cgit v1.2.3-58-ga151 From fb3d824d1a46c5bb0584ea88f32dc2495544aebf Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Mon, 9 May 2022 18:20:43 -0700 Subject: mm/rmap: split page_dup_rmap() into page_dup_file_rmap() and page_try_dup_anon_rmap() ... and move the special check for pinned pages into page_try_dup_anon_rmap() to prepare for tracking exclusive anonymous pages via a new pageflag, clearing it only after making sure that there are no GUP pins on the anonymous page. We really only care about pins on anonymous pages, because they are prone to getting replaced in the COW handler once mapped R/O. For !anon pages in cow-mappings (!VM_SHARED && VM_MAYWRITE) we shouldn't really care about that, at least not that I could come up with an example. Let's drop the is_cow_mapping() check from page_needs_cow_for_dma(), as we know we're dealing with anonymous pages. Also, drop the handling of pinned pages from copy_huge_pud() and add a comment if ever supporting anonymous pages on the PUD level. This is a preparation for tracking exclusivity of anonymous pages in the rmap code, and disallowing marking a page shared (-> failing to duplicate) if there are GUP pins on a page. Link: https://lkml.kernel.org/r/20220428083441.37290-5-david@redhat.com Signed-off-by: David Hildenbrand Acked-by: Vlastimil Babka Cc: Andrea Arcangeli Cc: Christoph Hellwig Cc: David Rientjes Cc: Don Dutile Cc: Hugh Dickins Cc: Jan Kara Cc: Jann Horn Cc: Jason Gunthorpe Cc: John Hubbard Cc: Khalid Aziz Cc: "Kirill A. Shutemov" Cc: Liang Zhang Cc: "Matthew Wilcox (Oracle)" Cc: Michal Hocko Cc: Mike Kravetz Cc: Mike Rapoport Cc: Nadav Amit Cc: Oded Gabbay Cc: Oleg Nesterov Cc: Pedro Demarchi Gomes Cc: Peter Xu Cc: Rik van Riel Cc: Roman Gushchin Cc: Shakeel Butt Cc: Yang Shi Signed-off-by: Andrew Morton --- include/linux/mm.h | 5 +---- include/linux/rmap.h | 49 ++++++++++++++++++++++++++++++++++++++++++++++++- mm/huge_memory.c | 27 ++++++++------------------- mm/hugetlb.c | 16 +++++++++------- mm/memory.c | 17 ++++++++++++----- mm/migrate.c | 2 +- 6 files changed, 79 insertions(+), 37 deletions(-) (limited to 'mm/migrate.c') diff --git a/include/linux/mm.h b/include/linux/mm.h index a02812178562..9ee3ae51e8e3 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1575,16 +1575,13 @@ static inline bool page_maybe_dma_pinned(struct page *page) /* * This should most likely only be called during fork() to see whether we - * should break the cow immediately for a page on the src mm. + * should break the cow immediately for an anon page on the src mm. * * The caller has to hold the PT lock and the vma->vm_mm->->write_protect_seq. */ static inline bool page_needs_cow_for_dma(struct vm_area_struct *vma, struct page *page) { - if (!is_cow_mapping(vma->vm_flags)) - return false; - VM_BUG_ON(!(raw_read_seqcount(&vma->vm_mm->write_protect_seq) & 1)); if (!test_bit(MMF_HAS_PINNED, &vma->vm_mm->flags)) diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 8573aae50d96..73f41544084f 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -12,6 +12,7 @@ #include #include #include +#include /* * The anon_vma heads a list of private "related" vmas, to scan if @@ -182,11 +183,57 @@ void hugepage_add_anon_rmap(struct page *, struct vm_area_struct *, void hugepage_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long address); -static inline void page_dup_rmap(struct page *page, bool compound) +static inline void __page_dup_rmap(struct page *page, bool compound) { atomic_inc(compound ? compound_mapcount_ptr(page) : &page->_mapcount); } +static inline void page_dup_file_rmap(struct page *page, bool compound) +{ + __page_dup_rmap(page, compound); +} + +/** + * page_try_dup_anon_rmap - try duplicating a mapping of an already mapped + * anonymous page + * @page: the page to duplicate the mapping for + * @compound: the page is mapped as compound or as a small page + * @vma: the source vma + * + * The caller needs to hold the PT lock and the vma->vma_mm->write_protect_seq. + * + * Duplicating the mapping can only fail if the page may be pinned; device + * private pages cannot get pinned and consequently this function cannot fail. + * + * If duplicating the mapping succeeds, the page has to be mapped R/O into + * the parent and the child. It must *not* get mapped writable after this call. + * + * Returns 0 if duplicating the mapping succeeded. Returns -EBUSY otherwise. + */ +static inline int page_try_dup_anon_rmap(struct page *page, bool compound, + struct vm_area_struct *vma) +{ + VM_BUG_ON_PAGE(!PageAnon(page), page); + + /* + * If this page may have been pinned by the parent process, + * don't allow to duplicate the mapping but instead require to e.g., + * copy the page immediately for the child so that we'll always + * guarantee the pinned page won't be randomly replaced in the + * future on write faults. + */ + if (likely(!is_device_private_page(page) && + unlikely(page_needs_cow_for_dma(vma, page)))) + return -EBUSY; + + /* + * It's okay to share the anon page between both processes, mapping + * the page R/O into both processes. + */ + __page_dup_rmap(page, compound); + return 0; +} + /* * Called from mm/vmscan.c to handle paging out */ diff --git a/mm/huge_memory.c b/mm/huge_memory.c index c468fee595ff..baf4ea6d8e1a 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1097,23 +1097,16 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, src_page = pmd_page(pmd); VM_BUG_ON_PAGE(!PageHead(src_page), src_page); - /* - * If this page is a potentially pinned page, split and retry the fault - * with smaller page size. Normally this should not happen because the - * userspace should use MADV_DONTFORK upon pinned regions. This is a - * best effort that the pinned pages won't be replaced by another - * random page during the coming copy-on-write. - */ - if (unlikely(page_needs_cow_for_dma(src_vma, src_page))) { + get_page(src_page); + if (unlikely(page_try_dup_anon_rmap(src_page, true, src_vma))) { + /* Page maybe pinned: split and retry the fault on PTEs. */ + put_page(src_page); pte_free(dst_mm, pgtable); spin_unlock(src_ptl); spin_unlock(dst_ptl); __split_huge_pmd(src_vma, src_pmd, addr, false, NULL); return -EAGAIN; } - - get_page(src_page); - page_dup_rmap(src_page, true); add_mm_counter(dst_mm, MM_ANONPAGES, HPAGE_PMD_NR); out_zero_page: mm_inc_nr_ptes(dst_mm); @@ -1217,14 +1210,10 @@ int copy_huge_pud(struct mm_struct *dst_mm, struct mm_struct *src_mm, /* No huge zero pud yet */ } - /* Please refer to comments in copy_huge_pmd() */ - if (unlikely(page_needs_cow_for_dma(vma, pud_page(pud)))) { - spin_unlock(src_ptl); - spin_unlock(dst_ptl); - __split_huge_pud(vma, src_pud, addr); - return -EAGAIN; - } - + /* + * TODO: once we support anonymous pages, use page_try_dup_anon_rmap() + * and split if duplicating fails. + */ pudp_set_wrprotect(src_mm, addr, src_pud); pud = pud_mkold(pud_wrprotect(pud)); set_pud_at(dst_mm, addr, dst_pud, pud); diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 7389cd8a9a87..7a6052a984e9 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -4806,15 +4806,18 @@ again: get_page(ptepage); /* - * This is a rare case where we see pinned hugetlb - * pages while they're prone to COW. We need to do the - * COW earlier during fork. + * Failing to duplicate the anon rmap is a rare case + * where we see pinned hugetlb pages while they're + * prone to COW. We need to do the COW earlier during + * fork. * * When pre-allocating the page or copying data, we * need to be without the pgtable locks since we could * sleep during the process. */ - if (unlikely(page_needs_cow_for_dma(vma, ptepage))) { + if (!PageAnon(ptepage)) { + page_dup_file_rmap(ptepage, true); + } else if (page_try_dup_anon_rmap(ptepage, true, vma)) { pte_t src_pte_old = entry; struct page *new; @@ -4861,7 +4864,6 @@ again: entry = huge_pte_wrprotect(entry); } - page_dup_rmap(ptepage, true); set_huge_pte_at(dst, addr, dst_pte, entry); hugetlb_count_add(npages, dst); } @@ -5541,7 +5543,7 @@ retry: ClearHPageRestoreReserve(page); hugepage_add_new_anon_rmap(page, vma, haddr); } else - page_dup_rmap(page, true); + page_dup_file_rmap(page, true); new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) && (vma->vm_flags & VM_SHARED))); set_huge_pte_at(mm, haddr, ptep, new_pte); @@ -5902,7 +5904,7 @@ int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, goto out_release_unlock; if (vm_shared) { - page_dup_rmap(page, true); + page_dup_file_rmap(page, true); } else { ClearHPageRestoreReserve(page); hugepage_add_new_anon_rmap(page, dst_vma, dst_addr); diff --git a/mm/memory.c b/mm/memory.c index 9bdfce15e98f..9f5f829a1b1f 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -825,7 +825,8 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, */ get_page(page); rss[mm_counter(page)]++; - page_dup_rmap(page, false); + /* Cannot fail as these pages cannot get pinned. */ + BUG_ON(page_try_dup_anon_rmap(page, false, src_vma)); /* * We do not preserve soft-dirty information, because so @@ -921,18 +922,24 @@ copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, struct page *page; page = vm_normal_page(src_vma, addr, pte); - if (page && unlikely(page_needs_cow_for_dma(src_vma, page))) { + if (page && PageAnon(page)) { /* * If this page may have been pinned by the parent process, * copy the page immediately for the child so that we'll always * guarantee the pinned page won't be randomly replaced in the * future. */ - return copy_present_page(dst_vma, src_vma, dst_pte, src_pte, - addr, rss, prealloc, page); + get_page(page); + if (unlikely(page_try_dup_anon_rmap(page, false, src_vma))) { + /* Page maybe pinned, we have to copy. */ + put_page(page); + return copy_present_page(dst_vma, src_vma, dst_pte, src_pte, + addr, rss, prealloc, page); + } + rss[mm_counter(page)]++; } else if (page) { get_page(page); - page_dup_rmap(page, false); + page_dup_file_rmap(page, false); rss[mm_counter(page)]++; } diff --git a/mm/migrate.c b/mm/migrate.c index 77592288fbc0..6ca6e89ded94 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -234,7 +234,7 @@ static bool remove_migration_pte(struct folio *folio, if (folio_test_anon(folio)) hugepage_add_anon_rmap(new, vma, pvmw.address); else - page_dup_rmap(new, true); + page_dup_file_rmap(new, true); set_huge_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte); } else #endif -- cgit v1.2.3-58-ga151 From f1e2db12e45baaa2d366f87c885968096c2ff5aa Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Mon, 9 May 2022 18:20:43 -0700 Subject: mm/rmap: remove do_page_add_anon_rmap() ... and instead convert page_add_anon_rmap() to accept flags. Passing flags instead of bools is usually nicer either way, and we want to more often also pass RMAP_EXCLUSIVE in follow up patches when detecting that an anonymous page is exclusive: for example, when restoring an anonymous page from a writable migration entry. This is a preparation for marking an anonymous page inside page_add_anon_rmap() as exclusive when RMAP_EXCLUSIVE is passed. Link: https://lkml.kernel.org/r/20220428083441.37290-7-david@redhat.com Signed-off-by: David Hildenbrand Acked-by: Vlastimil Babka Cc: Andrea Arcangeli Cc: Christoph Hellwig Cc: David Rientjes Cc: Don Dutile Cc: Hugh Dickins Cc: Jan Kara Cc: Jann Horn Cc: Jason Gunthorpe Cc: John Hubbard Cc: Khalid Aziz Cc: "Kirill A. Shutemov" Cc: Liang Zhang Cc: "Matthew Wilcox (Oracle)" Cc: Michal Hocko Cc: Mike Kravetz Cc: Mike Rapoport Cc: Nadav Amit Cc: Oded Gabbay Cc: Oleg Nesterov Cc: Pedro Demarchi Gomes Cc: Peter Xu Cc: Rik van Riel Cc: Roman Gushchin Cc: Shakeel Butt Cc: Yang Shi Signed-off-by: Andrew Morton --- include/linux/rmap.h | 2 -- mm/huge_memory.c | 2 +- mm/ksm.c | 2 +- mm/memory.c | 4 ++-- mm/migrate.c | 3 ++- mm/rmap.c | 14 +------------- mm/swapfile.c | 2 +- 7 files changed, 8 insertions(+), 21 deletions(-) (limited to 'mm/migrate.c') diff --git a/include/linux/rmap.h b/include/linux/rmap.h index c53a38151089..643801a937f3 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -183,8 +183,6 @@ typedef int __bitwise rmap_t; */ void page_move_anon_rmap(struct page *, struct vm_area_struct *); void page_add_anon_rmap(struct page *, struct vm_area_struct *, - unsigned long address, bool compound); -void do_page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long address, rmap_t flags); void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long address, bool compound); diff --git a/mm/huge_memory.c b/mm/huge_memory.c index baf4ea6d8e1a..6232b6817fab 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3072,7 +3072,7 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) pmde = pmd_wrprotect(pmd_mkuffd_wp(pmde)); if (PageAnon(new)) - page_add_anon_rmap(new, vma, mmun_start, true); + page_add_anon_rmap(new, vma, mmun_start, RMAP_COMPOUND); else page_add_file_rmap(new, vma, true); set_pmd_at(mm, mmun_start, pvmw->pmd, pmde); diff --git a/mm/ksm.c b/mm/ksm.c index 94bb0f049806..2b6692a7df6a 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -1156,7 +1156,7 @@ static int replace_page(struct vm_area_struct *vma, struct page *page, */ if (!is_zero_pfn(page_to_pfn(kpage))) { get_page(kpage); - page_add_anon_rmap(kpage, vma, addr, false); + page_add_anon_rmap(kpage, vma, addr, RMAP_NONE); newpte = mk_pte(kpage, vma->vm_page_prot); } else { newpte = pte_mkspecial(pfn_pte(page_to_pfn(kpage), diff --git a/mm/memory.c b/mm/memory.c index 4cd8cadf1268..8e92010f3d89 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -725,7 +725,7 @@ static void restore_exclusive_pte(struct vm_area_struct *vma, * created when the swap entry was made. */ if (PageAnon(page)) - page_add_anon_rmap(page, vma, address, false); + page_add_anon_rmap(page, vma, address, RMAP_NONE); else /* * Currently device exclusive access only supports anonymous @@ -3705,7 +3705,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) page_add_new_anon_rmap(page, vma, vmf->address, false); lru_cache_add_inactive_or_unevictable(page, vma); } else { - do_page_add_anon_rmap(page, vma, vmf->address, rmap_flags); + page_add_anon_rmap(page, vma, vmf->address, rmap_flags); } set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); diff --git a/mm/migrate.c b/mm/migrate.c index 6ca6e89ded94..381c7e05e8d4 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -240,7 +240,8 @@ static bool remove_migration_pte(struct folio *folio, #endif { if (folio_test_anon(folio)) - page_add_anon_rmap(new, vma, pvmw.address, false); + page_add_anon_rmap(new, vma, pvmw.address, + RMAP_NONE); else page_add_file_rmap(new, vma, false); set_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte); diff --git a/mm/rmap.c b/mm/rmap.c index 23a41132995e..a0cbbf201c98 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1171,7 +1171,7 @@ static void __page_check_anon_rmap(struct page *page, * @page: the page to add the mapping to * @vma: the vm area in which the mapping is added * @address: the user virtual address mapped - * @compound: charge the page as compound or small page + * @flags: the rmap flags * * The caller needs to hold the pte lock, and the page must be locked in * the anon_vma case: to serialize mapping,index checking after setting, @@ -1179,18 +1179,6 @@ static void __page_check_anon_rmap(struct page *page, * (but PageKsm is never downgraded to PageAnon). */ void page_add_anon_rmap(struct page *page, - struct vm_area_struct *vma, unsigned long address, bool compound) -{ - do_page_add_anon_rmap(page, vma, address, - compound ? RMAP_COMPOUND : RMAP_NONE); -} - -/* - * Special version of the above for do_swap_page, which often runs - * into pages that are exclusively owned by the current process. - * Everybody else should continue to use page_add_anon_rmap above. - */ -void do_page_add_anon_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address, rmap_t flags) { bool compound = flags & RMAP_COMPOUND; diff --git a/mm/swapfile.c b/mm/swapfile.c index 63c61f8b2611..1ba525a2179d 100644 --- a/mm/swapfile.c +++ b/mm/swapfile.c @@ -1800,7 +1800,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd, inc_mm_counter(vma->vm_mm, MM_ANONPAGES); get_page(page); if (page == swapcache) { - page_add_anon_rmap(page, vma, addr, false); + page_add_anon_rmap(page, vma, addr, RMAP_NONE); } else { /* ksm created a completely new copy */ page_add_new_anon_rmap(page, vma, addr, false); lru_cache_add_inactive_or_unevictable(page, vma); -- cgit v1.2.3-58-ga151 From 28c5209dfd5f86f4398ce01bfac8508b2c4d4050 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Mon, 9 May 2022 18:20:43 -0700 Subject: mm/rmap: pass rmap flags to hugepage_add_anon_rmap() Let's prepare for passing RMAP_EXCLUSIVE, similarly as we do for page_add_anon_rmap() now. RMAP_COMPOUND is implicit for hugetlb pages and ignored. Link: https://lkml.kernel.org/r/20220428083441.37290-8-david@redhat.com Signed-off-by: David Hildenbrand Acked-by: Vlastimil Babka Cc: Andrea Arcangeli Cc: Christoph Hellwig Cc: David Rientjes Cc: Don Dutile Cc: Hugh Dickins Cc: Jan Kara Cc: Jann Horn Cc: Jason Gunthorpe Cc: John Hubbard Cc: Khalid Aziz Cc: "Kirill A. Shutemov" Cc: Liang Zhang Cc: "Matthew Wilcox (Oracle)" Cc: Michal Hocko Cc: Mike Kravetz Cc: Mike Rapoport Cc: Nadav Amit Cc: Oded Gabbay Cc: Oleg Nesterov Cc: Pedro Demarchi Gomes Cc: Peter Xu Cc: Rik van Riel Cc: Roman Gushchin Cc: Shakeel Butt Cc: Yang Shi Signed-off-by: Andrew Morton --- include/linux/rmap.h | 2 +- mm/migrate.c | 3 ++- mm/rmap.c | 9 ++++++--- 3 files changed, 9 insertions(+), 5 deletions(-) (limited to 'mm/migrate.c') diff --git a/include/linux/rmap.h b/include/linux/rmap.h index 643801a937f3..90e1e6925789 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -191,7 +191,7 @@ void page_add_file_rmap(struct page *, struct vm_area_struct *, void page_remove_rmap(struct page *, struct vm_area_struct *, bool compound); void hugepage_add_anon_rmap(struct page *, struct vm_area_struct *, - unsigned long address); + unsigned long address, rmap_t flags); void hugepage_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long address); diff --git a/mm/migrate.c b/mm/migrate.c index 381c7e05e8d4..92e932f08be5 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -232,7 +232,8 @@ static bool remove_migration_pte(struct folio *folio, pte = pte_mkhuge(pte); pte = arch_make_huge_pte(pte, shift, vma->vm_flags); if (folio_test_anon(folio)) - hugepage_add_anon_rmap(new, vma, pvmw.address); + hugepage_add_anon_rmap(new, vma, pvmw.address, + RMAP_NONE); else page_dup_file_rmap(new, true); set_huge_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte); diff --git a/mm/rmap.c b/mm/rmap.c index a0cbbf201c98..32630f1b1ee1 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -2391,9 +2391,11 @@ void rmap_walk_locked(struct folio *folio, const struct rmap_walk_control *rwc) * The following two functions are for anonymous (private mapped) hugepages. * Unlike common anonymous pages, anonymous hugepages have no accounting code * and no lru code, because we handle hugepages differently from common pages. + * + * RMAP_COMPOUND is ignored. */ -void hugepage_add_anon_rmap(struct page *page, - struct vm_area_struct *vma, unsigned long address) +void hugepage_add_anon_rmap(struct page *page, struct vm_area_struct *vma, + unsigned long address, rmap_t flags) { struct anon_vma *anon_vma = vma->anon_vma; int first; @@ -2403,7 +2405,8 @@ void hugepage_add_anon_rmap(struct page *page, /* address might be in next vma when migration races vma_adjust */ first = atomic_inc_and_test(compound_mapcount_ptr(page)); if (first) - __page_set_anon_rmap(page, vma, address, 0); + __page_set_anon_rmap(page, vma, address, + !!(flags & RMAP_EXCLUSIVE)); } void hugepage_add_new_anon_rmap(struct page *page, -- cgit v1.2.3-58-ga151 From 6c287605fd56466e645693eff3ae7c08fba56e0a Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Mon, 9 May 2022 18:20:44 -0700 Subject: mm: remember exclusively mapped anonymous pages with PG_anon_exclusive Let's mark exclusively mapped anonymous pages with PG_anon_exclusive as exclusive, and use that information to make GUP pins reliable and stay consistent with the page mapped into the page table even if the page table entry gets write-protected. With that information at hand, we can extend our COW logic to always reuse anonymous pages that are exclusive. For anonymous pages that might be shared, the existing logic applies. As already documented, PG_anon_exclusive is usually only expressive in combination with a page table entry. Especially PTE vs. PMD-mapped anonymous pages require more thought, some examples: due to mremap() we can easily have a single compound page PTE-mapped into multiple page tables exclusively in a single process -- multiple page table locks apply. Further, due to MADV_WIPEONFORK we might not necessarily write-protect all PTEs, and only some subpages might be pinned. Long story short: once PTE-mapped, we have to track information about exclusivity per sub-page, but until then, we can just track it for the compound page in the head page and not having to update a whole bunch of subpages all of the time for a simple PMD mapping of a THP. For simplicity, this commit mostly talks about "anonymous pages", while it's for THP actually "the part of an anonymous folio referenced via a page table entry". To not spill PG_anon_exclusive code all over the mm code-base, we let the anon rmap code to handle all PG_anon_exclusive logic it can easily handle. If a writable, present page table entry points at an anonymous (sub)page, that (sub)page must be PG_anon_exclusive. If GUP wants to take a reliably pin (FOLL_PIN) on an anonymous page references via a present page table entry, it must only pin if PG_anon_exclusive is set for the mapped (sub)page. This commit doesn't adjust GUP, so this is only implicitly handled for FOLL_WRITE, follow-up commits will teach GUP to also respect it for FOLL_PIN without FOLL_WRITE, to make all GUP pins of anonymous pages fully reliable. Whenever an anonymous page is to be shared (fork(), KSM), or when temporarily unmapping an anonymous page (swap, migration), the relevant PG_anon_exclusive bit has to be cleared to mark the anonymous page possibly shared. Clearing will fail if there are GUP pins on the page: * For fork(), this means having to copy the page and not being able to share it. fork() protects against concurrent GUP using the PT lock and the src_mm->write_protect_seq. * For KSM, this means sharing will fail. For swap this means, unmapping will fail, For migration this means, migration will fail early. All three cases protect against concurrent GUP using the PT lock and a proper clear/invalidate+flush of the relevant page table entry. This fixes memory corruptions reported for FOLL_PIN | FOLL_WRITE, when a pinned page gets mapped R/O and the successive write fault ends up replacing the page instead of reusing it. It improves the situation for O_DIRECT/vmsplice/... that still use FOLL_GET instead of FOLL_PIN, if fork() is *not* involved, however swapout and fork() are still problematic. Properly using FOLL_PIN instead of FOLL_GET for these GUP users will fix the issue for them. I. Details about basic handling I.1. Fresh anonymous pages page_add_new_anon_rmap() and hugepage_add_new_anon_rmap() will mark the given page exclusive via __page_set_anon_rmap(exclusive=1). As that is the mechanism fresh anonymous pages come into life (besides migration code where we copy the page->mapping), all fresh anonymous pages will start out as exclusive. I.2. COW reuse handling of anonymous pages When a COW handler stumbles over a (sub)page that's marked exclusive, it simply reuses it. Otherwise, the handler tries harder under page lock to detect if the (sub)page is exclusive and can be reused. If exclusive, page_move_anon_rmap() will mark the given (sub)page exclusive. Note that hugetlb code does not yet check for PageAnonExclusive(), as it still uses the old COW logic that is prone to the COW security issue because hugetlb code cannot really tolerate unnecessary/wrong COW as huge pages are a scarce resource. I.3. Migration handling try_to_migrate() has to try marking an exclusive anonymous page shared via page_try_share_anon_rmap(). If it fails because there are GUP pins on the page, unmap fails. migrate_vma_collect_pmd() and __split_huge_pmd_locked() are handled similarly. Writable migration entries implicitly point at shared anonymous pages. For readable migration entries that information is stored via a new "readable-exclusive" migration entry, specific to anonymous pages. When restoring a migration entry in remove_migration_pte(), information about exlusivity is detected via the migration entry type, and RMAP_EXCLUSIVE is set accordingly for page_add_anon_rmap()/hugepage_add_anon_rmap() to restore that information. I.4. Swapout handling try_to_unmap() has to try marking the mapped page possibly shared via page_try_share_anon_rmap(). If it fails because there are GUP pins on the page, unmap fails. For now, information about exclusivity is lost. In the future, we might want to remember that information in the swap entry in some cases, however, it requires more thought, care, and a way to store that information in swap entries. I.5. Swapin handling do_swap_page() will never stumble over exclusive anonymous pages in the swap cache, as try_to_migrate() prohibits that. do_swap_page() always has to detect manually if an anonymous page is exclusive and has to set RMAP_EXCLUSIVE for page_add_anon_rmap() accordingly. I.6. THP handling __split_huge_pmd_locked() has to move the information about exclusivity from the PMD to the PTEs. a) In case we have a readable-exclusive PMD migration entry, simply insert readable-exclusive PTE migration entries. b) In case we have a present PMD entry and we don't want to freeze ("convert to migration entries"), simply forward PG_anon_exclusive to all sub-pages, no need to temporarily clear the bit. c) In case we have a present PMD entry and want to freeze, handle it similar to try_to_migrate(): try marking the page shared first. In case we fail, we ignore the "freeze" instruction and simply split ordinarily. try_to_migrate() will properly fail because the THP is still mapped via PTEs. When splitting a compound anonymous folio (THP), the information about exclusivity is implicitly handled via the migration entries: no need to replicate PG_anon_exclusive manually. I.7. fork() handling fork() handling is relatively easy, because PG_anon_exclusive is only expressive for some page table entry types. a) Present anonymous pages page_try_dup_anon_rmap() will mark the given subpage shared -- which will fail if the page is pinned. If it failed, we have to copy (or PTE-map a PMD to handle it on the PTE level). Note that device exclusive entries are just a pointer at a PageAnon() page. fork() will first convert a device exclusive entry to a present page table and handle it just like present anonymous pages. b) Device private entry Device private entries point at PageAnon() pages that cannot be mapped directly and, therefore, cannot get pinned. page_try_dup_anon_rmap() will mark the given subpage shared, which cannot fail because they cannot get pinned. c) HW poison entries PG_anon_exclusive will remain untouched and is stale -- the page table entry is just a placeholder after all. d) Migration entries Writable and readable-exclusive entries are converted to readable entries: possibly shared. I.8. mprotect() handling mprotect() only has to properly handle the new readable-exclusive migration entry: When write-protecting a migration entry that points at an anonymous page, remember the information about exclusivity via the "readable-exclusive" migration entry type. II. Migration and GUP-fast Whenever replacing a present page table entry that maps an exclusive anonymous page by a migration entry, we have to mark the page possibly shared and synchronize against GUP-fast by a proper clear/invalidate+flush to make the following scenario impossible: 1. try_to_migrate() places a migration entry after checking for GUP pins and marks the page possibly shared. 2. GUP-fast pins the page due to lack of synchronization 3. fork() converts the "writable/readable-exclusive" migration entry into a readable migration entry 4. Migration fails due to the GUP pin (failing to freeze the refcount) 5. Migration entries are restored. PG_anon_exclusive is lost -> We have a pinned page that is not marked exclusive anymore. Note that we move information about exclusivity from the page to the migration entry as it otherwise highly overcomplicates fork() and PTE-mapping a THP. III. Swapout and GUP-fast Whenever replacing a present page table entry that maps an exclusive anonymous page by a swap entry, we have to mark the page possibly shared and synchronize against GUP-fast by a proper clear/invalidate+flush to make the following scenario impossible: 1. try_to_unmap() places a swap entry after checking for GUP pins and clears exclusivity information on the page. 2. GUP-fast pins the page due to lack of synchronization. -> We have a pinned page that is not marked exclusive anymore. If we'd ever store information about exclusivity in the swap entry, similar to migration handling, the same considerations as in II would apply. This is future work. Link: https://lkml.kernel.org/r/20220428083441.37290-13-david@redhat.com Signed-off-by: David Hildenbrand Acked-by: Vlastimil Babka Cc: Andrea Arcangeli Cc: Christoph Hellwig Cc: David Rientjes Cc: Don Dutile Cc: Hugh Dickins Cc: Jan Kara Cc: Jann Horn Cc: Jason Gunthorpe Cc: John Hubbard Cc: Khalid Aziz Cc: "Kirill A. Shutemov" Cc: Liang Zhang Cc: "Matthew Wilcox (Oracle)" Cc: Michal Hocko Cc: Mike Kravetz Cc: Mike Rapoport Cc: Nadav Amit Cc: Oded Gabbay Cc: Oleg Nesterov Cc: Pedro Demarchi Gomes Cc: Peter Xu Cc: Rik van Riel Cc: Roman Gushchin Cc: Shakeel Butt Cc: Yang Shi Signed-off-by: Andrew Morton --- include/linux/rmap.h | 40 +++++++++++++++++++++++++ include/linux/swap.h | 15 +++++++--- include/linux/swapops.h | 25 ++++++++++++++++ mm/huge_memory.c | 78 ++++++++++++++++++++++++++++++++++++++++++++----- mm/hugetlb.c | 15 +++++++--- mm/ksm.c | 13 ++++++++- mm/memory.c | 33 ++++++++++++++++----- mm/migrate.c | 14 +++++++-- mm/migrate_device.c | 21 ++++++++++++- mm/mprotect.c | 8 +++-- mm/rmap.c | 61 ++++++++++++++++++++++++++++++++++---- 11 files changed, 289 insertions(+), 34 deletions(-) (limited to 'mm/migrate.c') diff --git a/include/linux/rmap.h b/include/linux/rmap.h index e4156921eea9..cbe279a6f0de 100644 --- a/include/linux/rmap.h +++ b/include/linux/rmap.h @@ -228,6 +228,13 @@ static inline int page_try_dup_anon_rmap(struct page *page, bool compound, { VM_BUG_ON_PAGE(!PageAnon(page), page); + /* + * No need to check+clear for already shared pages, including KSM + * pages. + */ + if (!PageAnonExclusive(page)) + goto dup; + /* * If this page may have been pinned by the parent process, * don't allow to duplicate the mapping but instead require to e.g., @@ -239,14 +246,47 @@ static inline int page_try_dup_anon_rmap(struct page *page, bool compound, unlikely(page_needs_cow_for_dma(vma, page)))) return -EBUSY; + ClearPageAnonExclusive(page); /* * It's okay to share the anon page between both processes, mapping * the page R/O into both processes. */ +dup: __page_dup_rmap(page, compound); return 0; } +/** + * page_try_share_anon_rmap - try marking an exclusive anonymous page possibly + * shared to prepare for KSM or temporary unmapping + * @page: the exclusive anonymous page to try marking possibly shared + * + * The caller needs to hold the PT lock and has to have the page table entry + * cleared/invalidated+flushed, to properly sync against GUP-fast. + * + * This is similar to page_try_dup_anon_rmap(), however, not used during fork() + * to duplicate a mapping, but instead to prepare for KSM or temporarily + * unmapping a page (swap, migration) via page_remove_rmap(). + * + * Marking the page shared can only fail if the page may be pinned; device + * private pages cannot get pinned and consequently this function cannot fail. + * + * Returns 0 if marking the page possibly shared succeeded. Returns -EBUSY + * otherwise. + */ +static inline int page_try_share_anon_rmap(struct page *page) +{ + VM_BUG_ON_PAGE(!PageAnon(page) || !PageAnonExclusive(page), page); + + /* See page_try_dup_anon_rmap(). */ + if (likely(!is_device_private_page(page) && + unlikely(page_maybe_dma_pinned(page)))) + return -EBUSY; + + ClearPageAnonExclusive(page); + return 0; +} + /* * Called from mm/vmscan.c to handle paging out */ diff --git a/include/linux/swap.h b/include/linux/swap.h index 27093b477c5f..e6d70a4156e8 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -78,12 +78,19 @@ static inline int current_is_kswapd(void) #endif /* - * NUMA node memory migration support + * Page migration support. + * + * SWP_MIGRATION_READ_EXCLUSIVE is only applicable to anonymous pages and + * indicates that the referenced (part of) an anonymous page is exclusive to + * a single process. For SWP_MIGRATION_WRITE, that information is implicit: + * (part of) an anonymous page that are mapped writable are exclusive to a + * single process. */ #ifdef CONFIG_MIGRATION -#define SWP_MIGRATION_NUM 2 -#define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM) -#define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1) +#define SWP_MIGRATION_NUM 3 +#define SWP_MIGRATION_READ (MAX_SWAPFILES + SWP_HWPOISON_NUM) +#define SWP_MIGRATION_READ_EXCLUSIVE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 1) +#define SWP_MIGRATION_WRITE (MAX_SWAPFILES + SWP_HWPOISON_NUM + 2) #else #define SWP_MIGRATION_NUM 0 #endif diff --git a/include/linux/swapops.h b/include/linux/swapops.h index 5af852b68805..6648b97244e7 100644 --- a/include/linux/swapops.h +++ b/include/linux/swapops.h @@ -194,6 +194,7 @@ static inline bool is_writable_device_exclusive_entry(swp_entry_t entry) static inline int is_migration_entry(swp_entry_t entry) { return unlikely(swp_type(entry) == SWP_MIGRATION_READ || + swp_type(entry) == SWP_MIGRATION_READ_EXCLUSIVE || swp_type(entry) == SWP_MIGRATION_WRITE); } @@ -202,11 +203,26 @@ static inline int is_writable_migration_entry(swp_entry_t entry) return unlikely(swp_type(entry) == SWP_MIGRATION_WRITE); } +static inline int is_readable_migration_entry(swp_entry_t entry) +{ + return unlikely(swp_type(entry) == SWP_MIGRATION_READ); +} + +static inline int is_readable_exclusive_migration_entry(swp_entry_t entry) +{ + return unlikely(swp_type(entry) == SWP_MIGRATION_READ_EXCLUSIVE); +} + static inline swp_entry_t make_readable_migration_entry(pgoff_t offset) { return swp_entry(SWP_MIGRATION_READ, offset); } +static inline swp_entry_t make_readable_exclusive_migration_entry(pgoff_t offset) +{ + return swp_entry(SWP_MIGRATION_READ_EXCLUSIVE, offset); +} + static inline swp_entry_t make_writable_migration_entry(pgoff_t offset) { return swp_entry(SWP_MIGRATION_WRITE, offset); @@ -224,6 +240,11 @@ static inline swp_entry_t make_readable_migration_entry(pgoff_t offset) return swp_entry(0, 0); } +static inline swp_entry_t make_readable_exclusive_migration_entry(pgoff_t offset) +{ + return swp_entry(0, 0); +} + static inline swp_entry_t make_writable_migration_entry(pgoff_t offset) { return swp_entry(0, 0); @@ -244,6 +265,10 @@ static inline int is_writable_migration_entry(swp_entry_t entry) { return 0; } +static inline int is_readable_migration_entry(swp_entry_t entry) +{ + return 0; +} #endif diff --git a/mm/huge_memory.c b/mm/huge_memory.c index cb5bcd833d9e..231911b7bf9d 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1054,7 +1054,7 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm, swp_entry_t entry = pmd_to_swp_entry(pmd); VM_BUG_ON(!is_pmd_migration_entry(pmd)); - if (is_writable_migration_entry(entry)) { + if (!is_readable_migration_entry(entry)) { entry = make_readable_migration_entry( swp_offset(entry)); pmd = swp_entry_to_pmd(entry); @@ -1292,6 +1292,10 @@ vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) page = pmd_page(orig_pmd); VM_BUG_ON_PAGE(!PageHead(page), page); + /* Early check when only holding the PT lock. */ + if (PageAnonExclusive(page)) + goto reuse; + if (!trylock_page(page)) { get_page(page); spin_unlock(vmf->ptl); @@ -1306,6 +1310,12 @@ vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) put_page(page); } + /* Recheck after temporarily dropping the PT lock. */ + if (PageAnonExclusive(page)) { + unlock_page(page); + goto reuse; + } + /* * See do_wp_page(): we can only map the page writable if there are * no additional references. Note that we always drain the LRU @@ -1319,11 +1329,12 @@ vm_fault_t do_huge_pmd_wp_page(struct vm_fault *vmf) pmd_t entry; page_move_anon_rmap(page, vma); + unlock_page(page); +reuse: entry = pmd_mkyoung(orig_pmd); entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma); if (pmdp_set_access_flags(vma, haddr, vmf->pmd, entry, 1)) update_mmu_cache_pmd(vma, vmf->address, vmf->pmd); - unlock_page(page); spin_unlock(vmf->ptl); return VM_FAULT_WRITE; } @@ -1708,6 +1719,7 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION if (is_swap_pmd(*pmd)) { swp_entry_t entry = pmd_to_swp_entry(*pmd); + struct page *page = pfn_swap_entry_to_page(entry); VM_BUG_ON(!is_pmd_migration_entry(*pmd)); if (is_writable_migration_entry(entry)) { @@ -1716,8 +1728,10 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, * A protection check is difficult so * just be safe and disable write */ - entry = make_readable_migration_entry( - swp_offset(entry)); + if (PageAnon(page)) + entry = make_readable_exclusive_migration_entry(swp_offset(entry)); + else + entry = make_readable_migration_entry(swp_offset(entry)); newpmd = swp_entry_to_pmd(entry); if (pmd_swp_soft_dirty(*pmd)) newpmd = pmd_swp_mksoft_dirty(newpmd); @@ -1937,6 +1951,7 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, pgtable_t pgtable; pmd_t old_pmd, _pmd; bool young, write, soft_dirty, pmd_migration = false, uffd_wp = false; + bool anon_exclusive = false; unsigned long addr; int i; @@ -2018,6 +2033,8 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, entry = pmd_to_swp_entry(old_pmd); page = pfn_swap_entry_to_page(entry); write = is_writable_migration_entry(entry); + if (PageAnon(page)) + anon_exclusive = is_readable_exclusive_migration_entry(entry); young = false; soft_dirty = pmd_swp_soft_dirty(old_pmd); uffd_wp = pmd_swp_uffd_wp(old_pmd); @@ -2029,8 +2046,26 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, young = pmd_young(old_pmd); soft_dirty = pmd_soft_dirty(old_pmd); uffd_wp = pmd_uffd_wp(old_pmd); + VM_BUG_ON_PAGE(!page_count(page), page); page_ref_add(page, HPAGE_PMD_NR - 1); + + /* + * Without "freeze", we'll simply split the PMD, propagating the + * PageAnonExclusive() flag for each PTE by setting it for + * each subpage -- no need to (temporarily) clear. + * + * With "freeze" we want to replace mapped pages by + * migration entries right away. This is only possible if we + * managed to clear PageAnonExclusive() -- see + * set_pmd_migration_entry(). + * + * In case we cannot clear PageAnonExclusive(), split the PMD + * only and let try_to_migrate_one() fail later. + */ + anon_exclusive = PageAnon(page) && PageAnonExclusive(page); + if (freeze && anon_exclusive && page_try_share_anon_rmap(page)) + freeze = false; } /* @@ -2052,6 +2087,9 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, if (write) swp_entry = make_writable_migration_entry( page_to_pfn(page + i)); + else if (anon_exclusive) + swp_entry = make_readable_exclusive_migration_entry( + page_to_pfn(page + i)); else swp_entry = make_readable_migration_entry( page_to_pfn(page + i)); @@ -2063,6 +2101,8 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, } else { entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); entry = maybe_mkwrite(entry, vma); + if (anon_exclusive) + SetPageAnonExclusive(page + i); if (!write) entry = pte_wrprotect(entry); if (!young) @@ -2294,6 +2334,13 @@ static void __split_huge_page_tail(struct page *head, int tail, * * After successful get_page_unless_zero() might follow flags change, * for example lock_page() which set PG_waiters. + * + * Note that for mapped sub-pages of an anonymous THP, + * PG_anon_exclusive has been cleared in unmap_page() and is stored in + * the migration entry instead from where remap_page() will restore it. + * We can still have PG_anon_exclusive set on effectively unmapped and + * unreferenced sub-pages of an anonymous THP: we can simply drop + * PG_anon_exclusive (-> PG_mappedtodisk) for these here. */ page_tail->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; page_tail->flags |= (head->flags & @@ -3025,6 +3072,7 @@ void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, struct vm_area_struct *vma = pvmw->vma; struct mm_struct *mm = vma->vm_mm; unsigned long address = pvmw->address; + bool anon_exclusive; pmd_t pmdval; swp_entry_t entry; pmd_t pmdswp; @@ -3034,10 +3082,19 @@ void set_pmd_migration_entry(struct page_vma_mapped_walk *pvmw, flush_cache_range(vma, address, address + HPAGE_PMD_SIZE); pmdval = pmdp_invalidate(vma, address, pvmw->pmd); + + anon_exclusive = PageAnon(page) && PageAnonExclusive(page); + if (anon_exclusive && page_try_share_anon_rmap(page)) { + set_pmd_at(mm, address, pvmw->pmd, pmdval); + return; + } + if (pmd_dirty(pmdval)) set_page_dirty(page); if (pmd_write(pmdval)) entry = make_writable_migration_entry(page_to_pfn(page)); + else if (anon_exclusive) + entry = make_readable_exclusive_migration_entry(page_to_pfn(page)); else entry = make_readable_migration_entry(page_to_pfn(page)); pmdswp = swp_entry_to_pmd(entry); @@ -3071,10 +3128,17 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new) if (pmd_swp_uffd_wp(*pvmw->pmd)) pmde = pmd_wrprotect(pmd_mkuffd_wp(pmde)); - if (PageAnon(new)) - page_add_anon_rmap(new, vma, mmun_start, RMAP_COMPOUND); - else + if (PageAnon(new)) { + rmap_t rmap_flags = RMAP_COMPOUND; + + if (!is_readable_migration_entry(entry)) + rmap_flags |= RMAP_EXCLUSIVE; + + page_add_anon_rmap(new, vma, mmun_start, rmap_flags); + } else { page_add_file_rmap(new, vma, true); + } + VM_BUG_ON(pmd_write(pmde) && PageAnon(new) && !PageAnonExclusive(new)); set_pmd_at(mm, mmun_start, pvmw->pmd, pmde); /* No need to invalidate - it was non-present before */ diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 03cbb75bcb54..c0012b4a8eec 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -4790,7 +4790,7 @@ again: is_hugetlb_entry_hwpoisoned(entry))) { swp_entry_t swp_entry = pte_to_swp_entry(entry); - if (is_writable_migration_entry(swp_entry) && cow) { + if (!is_readable_migration_entry(swp_entry) && cow) { /* * COW mappings require pages in both * parent and child to be set to read. @@ -5190,6 +5190,8 @@ retry_avoidcopy: set_huge_ptep_writable(vma, haddr, ptep); return 0; } + VM_BUG_ON_PAGE(PageAnon(old_page) && PageAnonExclusive(old_page), + old_page); /* * If the process that created a MAP_PRIVATE mapping is about to @@ -6187,12 +6189,17 @@ unsigned long hugetlb_change_protection(struct vm_area_struct *vma, } if (unlikely(is_hugetlb_entry_migration(pte))) { swp_entry_t entry = pte_to_swp_entry(pte); + struct page *page = pfn_swap_entry_to_page(entry); - if (is_writable_migration_entry(entry)) { + if (!is_readable_migration_entry(entry)) { pte_t newpte; - entry = make_readable_migration_entry( - swp_offset(entry)); + if (PageAnon(page)) + entry = make_readable_exclusive_migration_entry( + swp_offset(entry)); + else + entry = make_readable_migration_entry( + swp_offset(entry)); newpte = swp_entry_to_pte(entry); set_huge_swap_pte_at(mm, address, ptep, newpte, huge_page_size(h)); diff --git a/mm/ksm.c b/mm/ksm.c index 2b6692a7df6a..38360285497a 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -872,6 +872,7 @@ static inline struct stable_node *page_stable_node(struct page *page) static inline void set_page_stable_node(struct page *page, struct stable_node *stable_node) { + VM_BUG_ON_PAGE(PageAnon(page) && PageAnonExclusive(page), page); page->mapping = (void *)((unsigned long)stable_node | PAGE_MAPPING_KSM); } @@ -1044,6 +1045,7 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page, int swapped; int err = -EFAULT; struct mmu_notifier_range range; + bool anon_exclusive; pvmw.address = page_address_in_vma(page, vma); if (pvmw.address == -EFAULT) @@ -1061,9 +1063,10 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page, if (WARN_ONCE(!pvmw.pte, "Unexpected PMD mapping?")) goto out_unlock; + anon_exclusive = PageAnonExclusive(page); if (pte_write(*pvmw.pte) || pte_dirty(*pvmw.pte) || (pte_protnone(*pvmw.pte) && pte_savedwrite(*pvmw.pte)) || - mm_tlb_flush_pending(mm)) { + anon_exclusive || mm_tlb_flush_pending(mm)) { pte_t entry; swapped = PageSwapCache(page); @@ -1091,6 +1094,12 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page, set_pte_at(mm, pvmw.address, pvmw.pte, entry); goto out_unlock; } + + if (anon_exclusive && page_try_share_anon_rmap(page)) { + set_pte_at(mm, pvmw.address, pvmw.pte, entry); + goto out_unlock; + } + if (pte_dirty(entry)) set_page_dirty(page); @@ -1149,6 +1158,8 @@ static int replace_page(struct vm_area_struct *vma, struct page *page, pte_unmap_unlock(ptep, ptl); goto out_mn; } + VM_BUG_ON_PAGE(PageAnonExclusive(page), page); + VM_BUG_ON_PAGE(PageAnon(kpage) && PageAnonExclusive(kpage), kpage); /* * No need to check ksm_use_zero_pages here: we can only have a diff --git a/mm/memory.c b/mm/memory.c index 0b0727758c86..454ecc05ad85 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -720,6 +720,8 @@ static void restore_exclusive_pte(struct vm_area_struct *vma, else if (is_writable_device_exclusive_entry(entry)) pte = maybe_mkwrite(pte_mkdirty(pte), vma); + VM_BUG_ON(pte_write(pte) && !(PageAnon(page) && PageAnonExclusive(page))); + /* * No need to take a page reference as one was already * created when the swap entry was made. @@ -796,11 +798,12 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm, rss[mm_counter(page)]++; - if (is_writable_migration_entry(entry) && + if (!is_readable_migration_entry(entry) && is_cow_mapping(vm_flags)) { /* - * COW mappings require pages in both - * parent and child to be set to read. + * COW mappings require pages in both parent and child + * to be set to read. A previously exclusive entry is + * now shared. */ entry = make_readable_migration_entry( swp_offset(entry)); @@ -951,6 +954,7 @@ copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma, ptep_set_wrprotect(src_mm, addr, src_pte); pte = pte_wrprotect(pte); } + VM_BUG_ON(page && PageAnon(page) && PageAnonExclusive(page)); /* * If it's a shared mapping, mark it clean in @@ -2949,6 +2953,9 @@ static inline void wp_page_reuse(struct vm_fault *vmf) struct vm_area_struct *vma = vmf->vma; struct page *page = vmf->page; pte_t entry; + + VM_BUG_ON(PageAnon(page) && !PageAnonExclusive(page)); + /* * Clear the pages cpupid information as the existing * information potentially belongs to a now completely @@ -3273,6 +3280,13 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf) if (PageAnon(vmf->page)) { struct page *page = vmf->page; + /* + * If the page is exclusive to this process we must reuse the + * page without further checks. + */ + if (PageAnonExclusive(page)) + goto reuse; + /* * We have to verify under page lock: these early checks are * just an optimization to avoid locking the page and freeing @@ -3305,6 +3319,7 @@ static vm_fault_t do_wp_page(struct vm_fault *vmf) */ page_move_anon_rmap(page, vma); unlock_page(page); +reuse: wp_page_reuse(vmf); return VM_FAULT_WRITE; } else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) == @@ -3696,11 +3711,12 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) * that are certainly not shared because we just allocated them without * exposing them to the swapcache. */ - if ((vmf->flags & FAULT_FLAG_WRITE) && !PageKsm(page) && - (page != swapcache || page_count(page) == 1)) { - pte = maybe_mkwrite(pte_mkdirty(pte), vma); - vmf->flags &= ~FAULT_FLAG_WRITE; - ret |= VM_FAULT_WRITE; + if (!PageKsm(page) && (page != swapcache || page_count(page) == 1)) { + if (vmf->flags & FAULT_FLAG_WRITE) { + pte = maybe_mkwrite(pte_mkdirty(pte), vma); + vmf->flags &= ~FAULT_FLAG_WRITE; + ret |= VM_FAULT_WRITE; + } rmap_flags |= RMAP_EXCLUSIVE; } flush_icache_page(vma, page); @@ -3720,6 +3736,7 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) page_add_anon_rmap(page, vma, vmf->address, rmap_flags); } + VM_BUG_ON(!PageAnon(page) || (pte_write(pte) && !PageAnonExclusive(page))); set_pte_at(vma->vm_mm, vmf->address, vmf->pte, pte); arch_do_swap_page(vma->vm_mm, vma, vmf->address, pte, vmf->orig_pte); diff --git a/mm/migrate.c b/mm/migrate.c index 92e932f08be5..b2678279eb43 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -177,6 +177,7 @@ static bool remove_migration_pte(struct folio *folio, DEFINE_FOLIO_VMA_WALK(pvmw, old, vma, addr, PVMW_SYNC | PVMW_MIGRATION); while (page_vma_mapped_walk(&pvmw)) { + rmap_t rmap_flags = RMAP_NONE; pte_t pte; swp_entry_t entry; struct page *new; @@ -211,6 +212,9 @@ static bool remove_migration_pte(struct folio *folio, else if (pte_swp_uffd_wp(*pvmw.pte)) pte = pte_mkuffd_wp(pte); + if (folio_test_anon(folio) && !is_readable_migration_entry(entry)) + rmap_flags |= RMAP_EXCLUSIVE; + if (unlikely(is_device_private_page(new))) { if (pte_write(pte)) entry = make_writable_device_private_entry( @@ -233,7 +237,7 @@ static bool remove_migration_pte(struct folio *folio, pte = arch_make_huge_pte(pte, shift, vma->vm_flags); if (folio_test_anon(folio)) hugepage_add_anon_rmap(new, vma, pvmw.address, - RMAP_NONE); + rmap_flags); else page_dup_file_rmap(new, true); set_huge_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte); @@ -242,7 +246,7 @@ static bool remove_migration_pte(struct folio *folio, { if (folio_test_anon(folio)) page_add_anon_rmap(new, vma, pvmw.address, - RMAP_NONE); + rmap_flags); else page_add_file_rmap(new, vma, false); set_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte); @@ -514,6 +518,12 @@ void folio_migrate_flags(struct folio *newfolio, struct folio *folio) folio_set_workingset(newfolio); if (folio_test_checked(folio)) folio_set_checked(newfolio); + /* + * PG_anon_exclusive (-> PG_mappedtodisk) is always migrated via + * migration entries. We can still have PG_anon_exclusive set on an + * effectively unmapped and unreferenced first sub-pages of an + * anonymous THP: we can simply copy it here via PG_mappedtodisk. + */ if (folio_test_mappedtodisk(folio)) folio_set_mappedtodisk(newfolio); diff --git a/mm/migrate_device.c b/mm/migrate_device.c index fb6d7d5499f5..5052093d0262 100644 --- a/mm/migrate_device.c +++ b/mm/migrate_device.c @@ -184,15 +184,34 @@ again: * set up a special migration page table entry now. */ if (trylock_page(page)) { + bool anon_exclusive; pte_t swp_pte; + anon_exclusive = PageAnon(page) && PageAnonExclusive(page); + if (anon_exclusive) { + flush_cache_page(vma, addr, pte_pfn(*ptep)); + ptep_clear_flush(vma, addr, ptep); + + if (page_try_share_anon_rmap(page)) { + set_pte_at(mm, addr, ptep, pte); + unlock_page(page); + put_page(page); + mpfn = 0; + goto next; + } + } else { + ptep_get_and_clear(mm, addr, ptep); + } + migrate->cpages++; - ptep_get_and_clear(mm, addr, ptep); /* Setup special migration page table entry */ if (mpfn & MIGRATE_PFN_WRITE) entry = make_writable_migration_entry( page_to_pfn(page)); + else if (anon_exclusive) + entry = make_readable_exclusive_migration_entry( + page_to_pfn(page)); else entry = make_readable_migration_entry( page_to_pfn(page)); diff --git a/mm/mprotect.c b/mm/mprotect.c index b69ce7a7b2b7..56060acdabd3 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -152,6 +152,7 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, pages++; } else if (is_swap_pte(oldpte)) { swp_entry_t entry = pte_to_swp_entry(oldpte); + struct page *page = pfn_swap_entry_to_page(entry); pte_t newpte; if (is_writable_migration_entry(entry)) { @@ -159,8 +160,11 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, * A protection check is difficult so * just be safe and disable write */ - entry = make_readable_migration_entry( - swp_offset(entry)); + if (PageAnon(page)) + entry = make_readable_exclusive_migration_entry( + swp_offset(entry)); + else + entry = make_readable_migration_entry(swp_offset(entry)); newpte = swp_entry_to_pte(entry); if (pte_swp_soft_dirty(oldpte)) newpte = pte_swp_mksoft_dirty(newpte); diff --git a/mm/rmap.c b/mm/rmap.c index 90f92c53476f..0d63e7ce35cc 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1088,6 +1088,7 @@ int pfn_mkclean_range(unsigned long pfn, unsigned long nr_pages, pgoff_t pgoff, void page_move_anon_rmap(struct page *page, struct vm_area_struct *vma) { struct anon_vma *anon_vma = vma->anon_vma; + struct page *subpage = page; page = compound_head(page); @@ -1101,6 +1102,7 @@ void page_move_anon_rmap(struct page *page, struct vm_area_struct *vma) * folio_test_anon()) will not see one without the other. */ WRITE_ONCE(page->mapping, (struct address_space *) anon_vma); + SetPageAnonExclusive(subpage); } /** @@ -1118,7 +1120,7 @@ static void __page_set_anon_rmap(struct page *page, BUG_ON(!anon_vma); if (PageAnon(page)) - return; + goto out; /* * If the page isn't exclusively mapped into this vma, @@ -1137,6 +1139,9 @@ static void __page_set_anon_rmap(struct page *page, anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON; WRITE_ONCE(page->mapping, (struct address_space *) anon_vma); page->index = linear_page_index(vma, address); +out: + if (exclusive) + SetPageAnonExclusive(page); } /** @@ -1198,6 +1203,8 @@ void page_add_anon_rmap(struct page *page, } else { first = atomic_inc_and_test(&page->_mapcount); } + VM_BUG_ON_PAGE(!first && (flags & RMAP_EXCLUSIVE), page); + VM_BUG_ON_PAGE(!first && PageAnonExclusive(page), page); if (first) { int nr = compound ? thp_nr_pages(page) : 1; @@ -1459,7 +1466,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, address, 0); pte_t pteval; struct page *subpage; - bool ret = true; + bool anon_exclusive, ret = true; struct mmu_notifier_range range; enum ttu_flags flags = (enum ttu_flags)(long)arg; @@ -1515,6 +1522,8 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, subpage = folio_page(folio, pte_pfn(*pvmw.pte) - folio_pfn(folio)); address = pvmw.address; + anon_exclusive = folio_test_anon(folio) && + PageAnonExclusive(subpage); if (folio_test_hugetlb(folio) && !folio_test_anon(folio)) { /* @@ -1550,9 +1559,12 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, } } - /* Nuke the page table entry. */ + /* + * Nuke the page table entry. When having to clear + * PageAnonExclusive(), we always have to flush. + */ flush_cache_page(vma, address, pte_pfn(*pvmw.pte)); - if (should_defer_flush(mm, flags)) { + if (should_defer_flush(mm, flags) && !anon_exclusive) { /* * We clear the PTE but do not flush so potentially * a remote CPU could still be writing to the folio. @@ -1677,6 +1689,24 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, page_vma_mapped_walk_done(&pvmw); break; } + if (anon_exclusive && + page_try_share_anon_rmap(subpage)) { + swap_free(entry); + set_pte_at(mm, address, pvmw.pte, pteval); + ret = false; + page_vma_mapped_walk_done(&pvmw); + break; + } + /* + * Note: We *don't* remember yet if the page was mapped + * exclusively in the swap entry, so swapin code has + * to re-determine that manually and might detect the + * page as possibly shared, for example, if there are + * other references on the page or if the page is under + * writeback. We made sure that there are no GUP pins + * on the page that would rely on it, so for GUP pins + * this is fine. + */ if (list_empty(&mm->mmlist)) { spin_lock(&mmlist_lock); if (list_empty(&mm->mmlist)) @@ -1776,7 +1806,7 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, DEFINE_FOLIO_VMA_WALK(pvmw, folio, vma, address, 0); pte_t pteval; struct page *subpage; - bool ret = true; + bool anon_exclusive, ret = true; struct mmu_notifier_range range; enum ttu_flags flags = (enum ttu_flags)(long)arg; @@ -1837,6 +1867,8 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, subpage = folio_page(folio, pte_pfn(*pvmw.pte) - folio_pfn(folio)); address = pvmw.address; + anon_exclusive = folio_test_anon(folio) && + PageAnonExclusive(subpage); if (folio_test_hugetlb(folio) && !folio_test_anon(folio)) { /* @@ -1888,6 +1920,9 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, swp_entry_t entry; pte_t swp_pte; + if (anon_exclusive) + BUG_ON(page_try_share_anon_rmap(subpage)); + /* * Store the pfn of the page in a special migration * pte. do_swap_page() will wait until the migration @@ -1896,6 +1931,8 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, entry = pte_to_swp_entry(pteval); if (is_writable_device_private_entry(entry)) entry = make_writable_migration_entry(pfn); + else if (anon_exclusive) + entry = make_readable_exclusive_migration_entry(pfn); else entry = make_readable_migration_entry(pfn); swp_pte = swp_entry_to_pte(entry); @@ -1960,6 +1997,15 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, page_vma_mapped_walk_done(&pvmw); break; } + VM_BUG_ON_PAGE(pte_write(pteval) && folio_test_anon(folio) && + !anon_exclusive, subpage); + if (anon_exclusive && + page_try_share_anon_rmap(subpage)) { + set_pte_at(mm, address, pvmw.pte, pteval); + ret = false; + page_vma_mapped_walk_done(&pvmw); + break; + } /* * Store the pfn of the page in a special migration @@ -1969,6 +2015,9 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma, if (pte_write(pteval)) entry = make_writable_migration_entry( page_to_pfn(subpage)); + else if (anon_exclusive) + entry = make_readable_exclusive_migration_entry( + page_to_pfn(subpage)); else entry = make_readable_migration_entry( page_to_pfn(subpage)); @@ -2405,6 +2454,8 @@ void hugepage_add_anon_rmap(struct page *page, struct vm_area_struct *vma, BUG_ON(!anon_vma); /* address might be in next vma when migration races vma_adjust */ first = atomic_inc_and_test(compound_mapcount_ptr(page)); + VM_BUG_ON_PAGE(!first && (flags & RMAP_EXCLUSIVE), page); + VM_BUG_ON_PAGE(!first && PageAnonExclusive(page), page); if (first) __page_set_anon_rmap(page, vma, address, !!(flags & RMAP_EXCLUSIVE)); -- cgit v1.2.3-58-ga151 From 717aeab42943efa7cfa876b3b687c6ff36eae867 Mon Sep 17 00:00:00 2001 From: Jagdish Gediya Date: Thu, 12 May 2022 20:22:59 -0700 Subject: mm: convert sysfs input to bool using kstrtobool() Sysfs input conversion to corrosponding bool value e.g. "false" or "0" to false, "true" or "1" to true are currently handled through strncmp at multiple places. Use kstrtobool() to convert sysfs input to bool value. [akpm@linux-foundation.org: propagate kstrtobool() return value, per Andy] Link: https://lkml.kernel.org/r/20220426180203.70782-2-jvgediya@linux.ibm.com Signed-off-by: Jagdish Gediya Reviewed-by: Matthew Wilcox (Oracle) Reviewed-by: Andy Shevchenko Cc: Alexey Dobriyan Cc: Dave Hansen Cc: "Huang, Ying" Cc: Jonathan Cameron Cc: Petr Mladek Cc: Richard Fitzgerald Signed-off-by: Andrew Morton --- mm/migrate.c | 11 +++++------ mm/swap_state.c | 11 +++++------ 2 files changed, 10 insertions(+), 12 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index b2678279eb43..ab46ad93af9f 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2523,12 +2523,11 @@ static ssize_t numa_demotion_enabled_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { - if (!strncmp(buf, "true", 4) || !strncmp(buf, "1", 1)) - numa_demotion_enabled = true; - else if (!strncmp(buf, "false", 5) || !strncmp(buf, "0", 1)) - numa_demotion_enabled = false; - else - return -EINVAL; + ssize_t ret; + + ret = kstrtobool(buf, &numa_demotion_enabled); + if (ret) + return ret; return count; } diff --git a/mm/swap_state.c b/mm/swap_state.c index d41746a572a2..27c4e28f795f 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -874,12 +874,11 @@ static ssize_t vma_ra_enabled_store(struct kobject *kobj, struct kobj_attribute *attr, const char *buf, size_t count) { - if (!strncmp(buf, "true", 4) || !strncmp(buf, "1", 1)) - enable_vma_readahead = true; - else if (!strncmp(buf, "false", 5) || !strncmp(buf, "0", 1)) - enable_vma_readahead = false; - else - return -EINVAL; + ssize_t ret; + + ret = kstrtobool(buf, &enable_vma_readahead); + if (ret) + return ret; return count; } -- cgit v1.2.3-58-ga151 From e7e3ffeb274f1ff5bc68bb9135128e1ba14a7d53 Mon Sep 17 00:00:00 2001 From: "Matthew Wilcox (Oracle)" Date: Thu, 12 May 2022 20:23:05 -0700 Subject: mm/migrate: convert move_to_new_page() into move_to_new_folio() Pass in the folios that we already have in each caller. Saves a lot of calls to compound_head(). Link: https://lkml.kernel.org/r/20220504182857.4013401-27-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) Reviewed-by: Christoph Hellwig Signed-off-by: Andrew Morton --- mm/migrate.c | 58 +++++++++++++++++++++++++++++----------------------------- 1 file changed, 29 insertions(+), 29 deletions(-) (limited to 'mm/migrate.c') diff --git a/mm/migrate.c b/mm/migrate.c index ab46ad93af9f..1415ea25f7aa 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -843,21 +843,21 @@ static int fallback_migrate_page(struct address_space *mapping, * < 0 - error code * MIGRATEPAGE_SUCCESS - success */ -static int move_to_new_page(struct page *newpage, struct page *page, +static int move_to_new_folio(struct folio *dst, struct folio *src, enum migrate_mode mode) { struct address_space *mapping; int rc = -EAGAIN; - bool is_lru = !__PageMovable(page); + bool is_lru = !__PageMovable(&src->page); - VM_BUG_ON_PAGE(!PageLocked(page), page); - VM_BUG_ON_PAGE(!PageLocked(newpage), newpage); + VM_BUG_ON_FOLIO(!folio_test_locked(src), src); + VM_BUG_ON_FOLIO(!folio_test_locked(dst), dst); - mapping = page_mapping(page); + mapping = folio_mapping(src); if (likely(is_lru)) { if (!mapping) - rc = migrate_page(mapping, newpage, page, mode); + rc = migrate_page(mapping, &dst->page, &src->page, mode); else if (mapping->a_ops->migratepage) /* * Most pages have a mapping and most filesystems @@ -866,54 +866,54 @@ static int move_to_new_page(struct page *newpage, struct page *page, * migratepage callback. This is the most common path * for page migration. */ - rc = mapping->a_ops->migratepage(mapping, newpage, - page, mode); + rc = mapping->a_ops->migratepage(mapping, &dst->page, + &src->page, mode); else - rc = fallback_migrate_page(mapping, newpage, - page, mode); + rc = fallback_migrate_page(mapping, &dst->page, + &src->page, mode); } else { /* * In case of non-lru page, it could be released after * isolation step. In that case, we shouldn't try migration. */ - VM_BUG_ON_PAGE(!PageIsolated(page), page); - if (!PageMovable(page)) { + VM_BUG_ON_FOLIO(!folio_test_isolated(src), src); + if (!folio_test_movable(src)) { rc = MIGRATEPAGE_SUCCESS; - ClearPageIsolated(page); + folio_clear_isolated(src); goto out; } - rc = mapping->a_ops->migratepage(mapping, newpage, - page, mode); + rc = mapping->a_ops->migratepage(mapping, &dst->page, + &src->page, mode); WARN_ON_ONCE(rc == MIGRATEPAGE_SUCCESS && - !PageIsolated(page)); + !folio_test_isolated(src)); } /* - * When successful, old pagecache page->mapping must be cleared before - * page is freed; but stats require that PageAnon be left as PageAnon. + * When successful, old pagecache src->mapping must be cleared before + * src is freed; but stats require that PageAnon be left as PageAnon. */ if (rc == MIGRATEPAGE_SUCCESS) { - if (__PageMovable(page)) { - VM_BUG_ON_PAGE(!PageIsolated(page), page); + if (__PageMovable(&src->page)) { + VM_BUG_ON_FOLIO(!folio_test_isolated(src), src); /* * We clear PG_movable under page_lock so any compactor * cannot try to migrate this page. */ - ClearPageIsolated(page); + folio_clear_isolated(src); } /* - * Anonymous and movable page->mapping will be cleared by + * Anonymous and movable src->mapping will be cleared by * free_pages_prepare so don't reset it here for keeping * the type to work PageAnon, for example. */ - if (!PageMappingFlags(page)) - page->mapping = NULL; + if (!folio_mapping_flags(src)) + src->mapping = NULL; - if (likely(!is_zone_device_page(newpage))) - flush_dcache_folio(page_folio(newpage)); + if (likely(!folio_is_zone_device(dst))) + flush_dcache_folio(dst); } out: return rc; @@ -1001,7 +1001,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage, goto out_unlock; if (unlikely(!is_lru)) { - rc = move_to_new_page(newpage, page, mode); + rc = move_to_new_folio(dst, folio, mode); goto out_unlock_both; } @@ -1032,7 +1032,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage, } if (!page_mapped(page)) - rc = move_to_new_page(newpage, page, mode); + rc = move_to_new_folio(dst, folio, mode); /* * When successful, push newpage to LRU immediately: so that if it @@ -1261,7 +1261,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page, } if (!page_mapped(hpage)) - rc = move_to_new_page(new_hpage, hpage, mode); + rc = move_to_new_folio(dst, src, mode); if (page_was_mapped) remove_migration_ptes(src, -- cgit v1.2.3-58-ga151