From: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> Subject: mm: migrate: correct the hugetlb migration stats Correct the migration stats for hugetlb with using compound_nr() instead of thp_nr_pages(), meanwhile change 'nr_failed_pages' to record the number of normal pages failed to migrate, including THP and hugetlb, and 'nr_succeeded' will record the number of normal pages migrated successfully. [baolin.wang@xxxxxxxxxxxxxxxxx: fix docs, per Mike] Link: https://lkml.kernel.org/r/141bdfc6-f898-3cc3-f692-726c5f6cb74d@xxxxxxxxxxxxxxxxx Link: https://lkml.kernel.org/r/71a4b6c22f208728fe8c78ad26375436c4ff9704.1636275127.git.baolin.wang@xxxxxxxxxxxxxxxxx Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> Reviewed-by: Zi Yan <ziy@xxxxxxxxxx> Cc: Steven Rostedt (VMware) <rostedt@xxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- Documentation/vm/page_migration.rst | 12 ++++++------ mm/migrate.c | 17 ++++++++--------- 2 files changed, 14 insertions(+), 15 deletions(-) --- a/Documentation/vm/page_migration.rst~mm-migrate-correct-the-hugetlb-migration-stats +++ a/Documentation/vm/page_migration.rst @@ -263,15 +263,15 @@ Monitoring Migration The following events (counters) can be used to monitor page migration. 1. PGMIGRATE_SUCCESS: Normal page migration success. Each count means that a - page was migrated. If the page was a non-THP page, then this counter is - increased by one. If the page was a THP, then this counter is increased by - the number of THP subpages. For example, migration of a single 2MB THP that - has 4KB-size base pages (subpages) will cause this counter to increase by - 512. + page was migrated. If the page was a non-THP and non-hugetlb page, then + this counter is increased by one. If the page was a THP or hugetlb, then + this counter is increased by the number of THP or hugetlb subpages. + For example, migration of a single 2MB THP that has 4KB-size base pages + (subpages) will cause this counter to increase by 512. 2. PGMIGRATE_FAIL: Normal page migration failure. Same counting rules as for PGMIGRATE_SUCCESS, above: this will be increased by the number of subpages, - if it was a THP. + if it was a THP or hugetlb. 3. THP_MIGRATION_SUCCESS: A THP was migrated without being split. --- a/mm/migrate.c~mm-migrate-correct-the-hugetlb-migration-stats +++ a/mm/migrate.c @@ -1429,9 +1429,9 @@ static inline int try_split_thp(struct p * It is caller's responsibility to call putback_movable_pages() to return pages * to the LRU or free list only if ret != 0. * - * Returns the number of {normal page, THP} that were not migrated, or an error code. - * The number of THP splits will be considered as the number of non-migrated THP, - * no matter how many subpages of the THP are migrated successfully. + * Returns the number of {normal page, THP, hugetlb} that were not migrated, or + * an error code. The number of THP splits will be considered as the number of + * non-migrated THP, no matter how many subpages of the THP are migrated successfully. */ int migrate_pages(struct list_head *from, new_page_t get_new_page, free_page_t put_new_page, unsigned long private, @@ -1474,7 +1474,7 @@ retry: * during migration. */ is_thp = PageTransHuge(page) && !PageHuge(page); - nr_subpages = thp_nr_pages(page); + nr_subpages = compound_nr(page); cond_resched(); if (PageHuge(page)) @@ -1523,7 +1523,7 @@ retry: /* Hugetlb migration is unsupported */ if (!no_subpage_counting) nr_failed++; - nr_failed_pages++; + nr_failed_pages += nr_subpages; break; case -ENOMEM: /* @@ -1544,7 +1544,7 @@ retry: if (!no_subpage_counting) nr_failed++; - nr_failed_pages++; + nr_failed_pages += nr_subpages; goto out; case -EAGAIN: if (is_thp) { @@ -1554,12 +1554,11 @@ retry: retry++; break; case MIGRATEPAGE_SUCCESS: + nr_succeeded += nr_subpages; if (is_thp) { nr_thp_succeeded++; - nr_succeeded += nr_subpages; break; } - nr_succeeded++; break; default: /* @@ -1576,7 +1575,7 @@ retry: if (!no_subpage_counting) nr_failed++; - nr_failed_pages++; + nr_failed_pages += nr_subpages; break; } } _
