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Move hugetlb folios to a local list before migration and move any remaining folios to @ret_folios. This avoids scanning unrelated folios and removes the later hugetlb check from migrate_pages(). No functional change intended. Signed-off-by: Shivank Garg --- mm/migrate.c | 43 ++++++++++++++++++++++--------------------- 1 file changed, 22 insertions(+), 21 deletions(-) diff --git a/mm/migrate.c b/mm/migrate.c index 510dfffa7235..7a136cec275f 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1629,11 +1629,12 @@ struct migrate_pages_stats { }; /* - * Returns the number of hugetlb folios that were not migrated, or an error code - * after NR_MAX_MIGRATE_PAGES_RETRY attempts or if no hugetlb folios are movable - * any more because the list has become empty or no retryable hugetlb folios - * exist any more. It is caller's responsibility to call putback_movable_pages() - * only if ret != 0. + * Move hugetlb folios from @from to a local list and try to migrate each folio + * up to NR_MAX_MIGRATE_PAGES_RETRY times. Any remaining folios are moved to + * @ret_folios list. + * + * Return the number of failed folios, or a negative errno. + * */ static int migrate_hugetlbs(struct list_head *from, new_folio_t get_new_folio, free_folio_t put_new_folio, unsigned long private, @@ -1646,16 +1647,18 @@ static int migrate_hugetlbs(struct list_head *from, new_folio_t get_new_folio, int nr_retry_pages = 0; int pass = 0; struct folio *folio, *folio2; - int rc, nr_pages; + int rc, ret, nr_pages; + LIST_HEAD(hugetlbs); + + list_for_each_entry_safe(folio, folio2, from, lru) + if (folio_test_hugetlb(folio)) + list_move_tail(&folio->lru, &hugetlbs); for (pass = 0; pass < NR_MAX_MIGRATE_PAGES_RETRY && retry; pass++) { retry = 0; nr_retry_pages = 0; - list_for_each_entry_safe(folio, folio2, from, lru) { - if (!folio_test_hugetlb(folio)) - continue; - + list_for_each_entry_safe(folio, folio2, &hugetlbs, lru) { nr_pages = folio_nr_pages(folio); cond_resched(); @@ -1681,18 +1684,19 @@ static int migrate_hugetlbs(struct list_head *from, new_folio_t get_new_folio, /* * The rules are: * 0: hugetlb folio will be put back - * -EAGAIN: stay on the from list - * -ENOMEM: stay on the from list + * -EAGAIN: stay on hugetlbs, retried by a later pass + * -ENOMEM: give up; rest of the list goes to ret_folios * Other errno: put on ret_folios list */ - switch(rc) { + switch (rc) { case -ENOMEM: /* * When memory is low, don't bother to try to migrate * other folios, just exit. */ stats->nr_failed_pages += nr_pages + nr_retry_pages; - return -ENOMEM; + ret = -ENOMEM; + goto out; case -EAGAIN: retry++; nr_retry_pages += nr_pages; @@ -1720,8 +1724,11 @@ static int migrate_hugetlbs(struct list_head *from, new_folio_t get_new_folio, */ nr_failed += retry; stats->nr_failed_pages += nr_retry_pages; + ret = nr_failed; +out: + list_splice_tail(&hugetlbs, ret_folios); - return nr_failed; + return ret; } static void migrate_folios_move(struct list_head *src_folios, @@ -2161,12 +2168,6 @@ int migrate_pages(struct list_head *from, new_folio_t get_new_folio, again: nr_pages = 0; list_for_each_entry_safe(folio, folio2, from, lru) { - /* Retried hugetlb folios will be kept in list */ - if (folio_test_hugetlb(folio)) { - list_move_tail(&folio->lru, &ret_folios); - continue; - } - nr_pages += folio_nr_pages(folio); if (nr_pages >= NR_MAX_BATCHED_MIGRATION) break; -- 2.43.0