From 0adbd047a01ee19615328b56c3c6bd73f280bcbc Mon Sep 17 00:00:00 2001 From: Zi Yan Date: Mon, 22 Apr 2024 17:46:40 +0800 Subject: [PATCH 1/2] mm/migrate: correct nr_failed in migrate_pages_sync() mainline inclusion from mainline-v6.7-rc1 commit a259945efe6ada94087ef666e9b38f8e34ea34ba category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9IP8P CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a259945efe6ada94087ef666e9b38f8e34ea34ba -------------------------------- nr_failed was missing the large folio splits from migrate_pages_batch() and can cause a mismatch between migrate_pages() return value and the number of not migrated pages, i.e., when the return value of migrate_pages() is 0, there are still pages left in the from page list. It will happen when a non-PMD THP large folio fails to migrate due to -ENOMEM and is split successfully but not all the split pages are not migrated, migrate_pages_batch() would return non-zero, but astats.nr_thp_split = 0. nr_failed would be 0 and returned to the caller of migrate_pages(), but the not migrated pages are left in the from page list without being added back to LRU lists. Fix it by adding a new nr_split counter for large folio splits and adding it to nr_failed in migrate_page_sync() after migrate_pages_batch() is done. Link: https://lkml.kernel.org/r/20231017163129.2025214-1-zi.yan@sent.com Fixes: 2ef7dbb26990 ("migrate_pages: try migrate in batch asynchronously firstly") Signed-off-by: Zi Yan Acked-by: Huang Ying Reviewed-by: Baolin Wang Cc: David Hildenbrand Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Liu Shixin --- mm/migrate.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index bdcf75f2b320..7089c78ad952 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1511,6 +1511,7 @@ struct migrate_pages_stats { int nr_thp_succeeded; /* THP migrated successfully */ int nr_thp_failed; /* THP failed to be migrated */ int nr_thp_split; /* THP split before migrating */ + int nr_split; /* Large folio (include THP) split before migrating */ }; /* @@ -1630,6 +1631,7 @@ static int migrate_pages_batch(struct list_head *from, int nr_retry_pages = 0; int pass = 0; bool is_thp = false; + bool is_large = false; struct folio *folio, *folio2, *dst = NULL, *dst2; int rc, rc_saved = 0, nr_pages; LIST_HEAD(unmap_folios); @@ -1645,7 +1647,8 @@ static int migrate_pages_batch(struct list_head *from, nr_retry_pages = 0; list_for_each_entry_safe(folio, folio2, from, lru) { - is_thp = folio_test_large(folio) && folio_test_pmd_mappable(folio); + is_large = folio_test_large(folio); + is_thp = is_large && folio_test_pmd_mappable(folio); nr_pages = folio_nr_pages(folio); cond_resched(); @@ -1665,6 +1668,7 @@ static int migrate_pages_batch(struct list_head *from, stats->nr_thp_failed++; if (!try_split_folio(folio, split_folios)) { stats->nr_thp_split++; + stats->nr_split++; continue; } stats->nr_failed_pages += nr_pages; @@ -1693,11 +1697,12 @@ static int migrate_pages_batch(struct list_head *from, nr_failed++; stats->nr_thp_failed += is_thp; /* Large folio NUMA faulting doesn't split to retry. */ - if (folio_test_large(folio) && !nosplit) { + if (is_large && !nosplit) { int ret = try_split_folio(folio, split_folios); if (!ret) { stats->nr_thp_split += is_thp; + stats->nr_split += is_large; break; } else if (reason == MR_LONGTERM_PIN && ret == -EAGAIN) { @@ -1843,6 +1848,7 @@ static int migrate_pages_sync(struct list_head *from, new_folio_t get_new_folio, stats->nr_succeeded += astats.nr_succeeded; stats->nr_thp_succeeded += astats.nr_thp_succeeded; stats->nr_thp_split += astats.nr_thp_split; + stats->nr_split += astats.nr_split; if (rc < 0) { stats->nr_failed_pages += astats.nr_failed_pages; stats->nr_thp_failed += astats.nr_thp_failed; @@ -1850,7 +1856,11 @@ static int migrate_pages_sync(struct list_head *from, new_folio_t get_new_folio, return rc; } stats->nr_thp_failed += astats.nr_thp_split; - nr_failed += astats.nr_thp_split; + /* + * Do not count rc, as pages will be retried below. + * Count nr_split only, since it includes nr_thp_split. + */ + nr_failed += astats.nr_split; /* * Fall back to migrate all failed folios one by one synchronously. All * failed folios except split THPs will be retried, so their failure -- Gitee From 57dc916b5204287bf2f3b6fb71a3a74fa54cd8cc Mon Sep 17 00:00:00 2001 From: Zi Yan Date: Mon, 22 Apr 2024 17:46:41 +0800 Subject: [PATCH 2/2] mm/migrate: add nr_split to trace_mm_migrate_pages stats. mainline inclusion from mainline-v6.7-rc1 commit 49cac03a8f0a56cafa5329911564c97c130ced43 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I9IP8P CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=49cac03a8f0a56cafa5329911564c97c130ced43 -------------------------------- Add nr_split to trace_mm_migrate_pages for large folio (including THP) split events. [akpm@linux-foundation.org: cleanup per Huang, Ying] Link: https://lkml.kernel.org/r/20231017163129.2025214-2-zi.yan@sent.com Signed-off-by: Zi Yan Reviewed-by: "Huang, Ying" Reviewed-by: Baolin Wang Cc: David Hildenbrand Cc: Huang Ying Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Liu Shixin --- include/trace/events/migrate.h | 24 ++++++++++++++---------- mm/migrate.c | 5 +++-- 2 files changed, 17 insertions(+), 12 deletions(-) diff --git a/include/trace/events/migrate.h b/include/trace/events/migrate.h index 061b5128f335..0190ef725b43 100644 --- a/include/trace/events/migrate.h +++ b/include/trace/events/migrate.h @@ -49,10 +49,11 @@ TRACE_EVENT(mm_migrate_pages, TP_PROTO(unsigned long succeeded, unsigned long failed, unsigned long thp_succeeded, unsigned long thp_failed, - unsigned long thp_split, enum migrate_mode mode, int reason), + unsigned long thp_split, unsigned long large_folio_split, + enum migrate_mode mode, int reason), TP_ARGS(succeeded, failed, thp_succeeded, thp_failed, - thp_split, mode, reason), + thp_split, large_folio_split, mode, reason), TP_STRUCT__entry( __field( unsigned long, succeeded) @@ -60,26 +61,29 @@ TRACE_EVENT(mm_migrate_pages, __field( unsigned long, thp_succeeded) __field( unsigned long, thp_failed) __field( unsigned long, thp_split) + __field( unsigned long, large_folio_split) __field( enum migrate_mode, mode) __field( int, reason) ), TP_fast_assign( - __entry->succeeded = succeeded; - __entry->failed = failed; - __entry->thp_succeeded = thp_succeeded; - __entry->thp_failed = thp_failed; - __entry->thp_split = thp_split; - __entry->mode = mode; - __entry->reason = reason; + __entry->succeeded = succeeded; + __entry->failed = failed; + __entry->thp_succeeded = thp_succeeded; + __entry->thp_failed = thp_failed; + __entry->thp_split = thp_split; + __entry->large_folio_split = large_folio_split; + __entry->mode = mode; + __entry->reason = reason; ), - TP_printk("nr_succeeded=%lu nr_failed=%lu nr_thp_succeeded=%lu nr_thp_failed=%lu nr_thp_split=%lu mode=%s reason=%s", + TP_printk("nr_succeeded=%lu nr_failed=%lu nr_thp_succeeded=%lu nr_thp_failed=%lu nr_thp_split=%lu nr_split=%lu mode=%s reason=%s", __entry->succeeded, __entry->failed, __entry->thp_succeeded, __entry->thp_failed, __entry->thp_split, + __entry->large_folio_split, __print_symbolic(__entry->mode, MIGRATE_MODE), __print_symbolic(__entry->reason, MIGRATE_REASON)) ); diff --git a/mm/migrate.c b/mm/migrate.c index 7089c78ad952..cd2a24c6a745 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1702,7 +1702,7 @@ static int migrate_pages_batch(struct list_head *from, if (!ret) { stats->nr_thp_split += is_thp; - stats->nr_split += is_large; + stats->nr_split++; break; } else if (reason == MR_LONGTERM_PIN && ret == -EAGAIN) { @@ -1995,7 +1995,8 @@ int migrate_pages(struct list_head *from, new_folio_t get_new_folio, count_vm_events(THP_MIGRATION_SPLIT, stats.nr_thp_split); trace_mm_migrate_pages(stats.nr_succeeded, stats.nr_failed_pages, stats.nr_thp_succeeded, stats.nr_thp_failed, - stats.nr_thp_split, mode, reason); + stats.nr_thp_split, stats.nr_split, mode, + reason); if (ret_succeeded) *ret_succeeded = stats.nr_succeeded; -- Gitee