]> git.ipfire.org Git - thirdparty/linux.git/commitdiff
migrate: convert migrate_pages() to use folios
authorHuang Ying <ying.huang@intel.com>
Wed, 9 Nov 2022 01:23:48 +0000 (09:23 +0800)
committerAndrew Morton <akpm@linux-foundation.org>
Wed, 30 Nov 2022 23:58:54 +0000 (15:58 -0800)
Quite straightforward, the page functions are converted to corresponding
folio functions.  Same for comments.

THP specific code are converted to be large folio.

Link: https://lkml.kernel.org/r/20221109012348.93849-3-ying.huang@intel.com
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
mm/migrate.c

index e41a3cd24a5982cf580a15381819787fb0569588..4aa3b6d4f67c92fee1f94c37ca8db6928836645c 100644 (file)
@@ -1373,231 +1373,245 @@ out:
        return rc;
 }
 
-static inline int try_split_thp(struct page *page, struct list_head *split_pages)
+static inline int try_split_folio(struct folio *folio, struct list_head *split_folios)
 {
        int rc;
 
-       lock_page(page);
-       rc = split_huge_page_to_list(page, split_pages);
-       unlock_page(page);
+       folio_lock(folio);
+       rc = split_folio_to_list(folio, split_folios);
+       folio_unlock(folio);
        if (!rc)
-               list_move_tail(&page->lru, split_pages);
+               list_move_tail(&folio->lru, split_folios);
 
        return rc;
 }
 
 /*
- * migrate_pages - migrate the pages specified in a list, to the free pages
+ * migrate_pages - migrate the folios specified in a list, to the free folios
  *                supplied as the target for the page migration
  *
- * @from:              The list of pages to be migrated.
- * @get_new_page:      The function used to allocate free pages to be used
- *                     as the target of the page migration.
- * @put_new_page:      The function used to free target pages if migration
+ * @from:              The list of folios to be migrated.
+ * @get_new_page:      The function used to allocate free folios to be used
+ *                     as the target of the folio migration.
+ * @put_new_page:      The function used to free target folios if migration
  *                     fails, or NULL if no special handling is necessary.
  * @private:           Private data to be passed on to get_new_page()
  * @mode:              The migration mode that specifies the constraints for
- *                     page migration, if any.
- * @reason:            The reason for page migration.
- * @ret_succeeded:     Set to the number of normal pages migrated successfully if
+ *                     folio migration, if any.
+ * @reason:            The reason for folio migration.
+ * @ret_succeeded:     Set to the number of folios migrated successfully if
  *                     the caller passes a non-NULL pointer.
  *
- * The function returns after 10 attempts or if no pages are movable any more
- * because the list has become empty or no retryable pages exist any more.
- * It is caller's responsibility to call putback_movable_pages() to return pages
+ * The function returns after 10 attempts or if no folios are movable any more
+ * because the list has become empty or no retryable folios exist any more.
+ * It is caller's responsibility to call putback_movable_pages() to return folios
  * to the LRU or free list only if ret != 0.
  *
- * 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.
+ * Returns the number of {normal folio, large folio, hugetlb} that were not
+ * migrated, or an error code. The number of large folio splits will be
+ * considered as the number of non-migrated large folio, no matter how many
+ * split folios of the large folio 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,
                enum migrate_mode mode, int reason, unsigned int *ret_succeeded)
 {
        int retry = 1;
+       int large_retry = 1;
        int thp_retry = 1;
        int nr_failed = 0;
        int nr_failed_pages = 0;
        int nr_retry_pages = 0;
        int nr_succeeded = 0;
        int nr_thp_succeeded = 0;
+       int nr_large_failed = 0;
        int nr_thp_failed = 0;
        int nr_thp_split = 0;
        int pass = 0;
+       bool is_large = false;
        bool is_thp = false;
-       struct page *page;
-       struct page *page2;
-       int rc, nr_subpages;
-       LIST_HEAD(ret_pages);
-       LIST_HEAD(thp_split_pages);
+       struct folio *folio, *folio2;
+       int rc, nr_pages;
+       LIST_HEAD(ret_folios);
+       LIST_HEAD(split_folios);
        bool nosplit = (reason == MR_NUMA_MISPLACED);
-       bool no_subpage_counting = false;
+       bool no_split_folio_counting = false;
 
        trace_mm_migrate_pages_start(mode, reason);
 
-thp_subpage_migration:
-       for (pass = 0; pass < 10 && (retry || thp_retry); pass++) {
+split_folio_migration:
+       for (pass = 0; pass < 10 && (retry || large_retry); pass++) {
                retry = 0;
+               large_retry = 0;
                thp_retry = 0;
                nr_retry_pages = 0;
 
-               list_for_each_entry_safe(page, page2, from, lru) {
+               list_for_each_entry_safe(folio, folio2, from, lru) {
                        /*
-                        * THP statistics is based on the source huge page.
-                        * Capture required information that might get lost
-                        * during migration.
+                        * Large folio statistics is based on the source large
+                        * folio. Capture required information that might get
+                        * lost during migration.
                         */
-                       is_thp = PageTransHuge(page) && !PageHuge(page);
-                       nr_subpages = compound_nr(page);
+                       is_large = folio_test_large(folio) && !folio_test_hugetlb(folio);
+                       is_thp = is_large && folio_test_pmd_mappable(folio);
+                       nr_pages = folio_nr_pages(folio);
                        cond_resched();
 
-                       if (PageHuge(page))
+                       if (folio_test_hugetlb(folio))
                                rc = unmap_and_move_huge_page(get_new_page,
-                                               put_new_page, private, page,
-                                               pass > 2, mode, reason,
-                                               &ret_pages);
+                                               put_new_page, private,
+                                               &folio->page, pass > 2, mode,
+                                               reason,
+                                               &ret_folios);
                        else
                                rc = unmap_and_move(get_new_page, put_new_page,
-                                               private, page_folio(page), pass > 2, mode,
-                                               reason, &ret_pages);
+                                               private, folio, pass > 2, mode,
+                                               reason, &ret_folios);
                        /*
                         * The rules are:
-                        *      Success: non hugetlb page will be freed, hugetlb
-                        *               page will be put back
+                        *      Success: non hugetlb folio will be freed, hugetlb
+                        *               folio will be put back
                         *      -EAGAIN: stay on the from list
                         *      -ENOMEM: stay on the from list
                         *      -ENOSYS: stay on the from list
-                        *      Other errno: put on ret_pages list then splice to
+                        *      Other errno: put on ret_folios list then splice to
                         *                   from list
                         */
                        switch(rc) {
                        /*
-                        * THP migration might be unsupported or the
-                        * allocation could've failed so we should
-                        * retry on the same page with the THP split
-                        * to base pages.
+                        * Large folio migration might be unsupported or
+                        * the allocation could've failed so we should retry
+                        * on the same folio with the large folio split
+                        * to normal folios.
                         *
-                        * Sub-pages are put in thp_split_pages, and
+                        * Split folios are put in split_folios, and
                         * we will migrate them after the rest of the
                         * list is processed.
                         */
                        case -ENOSYS:
-                               /* THP migration is unsupported */
-                               if (is_thp) {
-                                       nr_thp_failed++;
-                                       if (!try_split_thp(page, &thp_split_pages)) {
-                                               nr_thp_split++;
+                               /* Large folio migration is unsupported */
+                               if (is_large) {
+                                       nr_large_failed++;
+                                       nr_thp_failed += is_thp;
+                                       if (!try_split_folio(folio, &split_folios)) {
+                                               nr_thp_split += is_thp;
                                                break;
                                        }
                                /* Hugetlb migration is unsupported */
-                               } else if (!no_subpage_counting) {
+                               } else if (!no_split_folio_counting) {
                                        nr_failed++;
                                }
 
-                               nr_failed_pages += nr_subpages;
-                               list_move_tail(&page->lru, &ret_pages);
+                               nr_failed_pages += nr_pages;
+                               list_move_tail(&folio->lru, &ret_folios);
                                break;
                        case -ENOMEM:
                                /*
                                 * When memory is low, don't bother to try to migrate
-                                * other pages, just exit.
+                                * other folios, just exit.
                                 */
-                               if (is_thp) {
-                                       nr_thp_failed++;
-                                       /* THP NUMA faulting doesn't split THP to retry. */
+                               if (is_large) {
+                                       nr_large_failed++;
+                                       nr_thp_failed += is_thp;
+                                       /* Large folio NUMA faulting doesn't split to retry. */
                                        if (!nosplit) {
-                                               int ret = try_split_thp(page, &thp_split_pages);
+                                               int ret = try_split_folio(folio, &split_folios);
 
                                                if (!ret) {
-                                                       nr_thp_split++;
+                                                       nr_thp_split += is_thp;
                                                        break;
                                                } else if (reason == MR_LONGTERM_PIN &&
                                                           ret == -EAGAIN) {
                                                        /*
-                                                        * Try again to split THP to mitigate
-                                                        * the failure of longterm pinning.
+                                                        * Try again to split large folio to
+                                                        * mitigate the failure of longterm pinning.
                                                         */
-                                                       thp_retry++;
-                                                       nr_retry_pages += nr_subpages;
+                                                       large_retry++;
+                                                       thp_retry += is_thp;
+                                                       nr_retry_pages += nr_pages;
                                                        break;
                                                }
                                        }
-                               } else if (!no_subpage_counting) {
+                               } else if (!no_split_folio_counting) {
                                        nr_failed++;
                                }
 
-                               nr_failed_pages += nr_subpages + nr_retry_pages;
+                               nr_failed_pages += nr_pages + nr_retry_pages;
                                /*
-                                * There might be some subpages of fail-to-migrate THPs
-                                * left in thp_split_pages list. Move them back to migration
+                                * There might be some split folios of fail-to-migrate large
+                                * folios left in split_folios 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.
+                                * the caller otherwise the folio refcnt will be leaked.
                                 */
-                               list_splice_init(&thp_split_pages, from);
+                               list_splice_init(&split_folios, from);
                                /* nr_failed isn't updated for not used */
+                               nr_large_failed += large_retry;
                                nr_thp_failed += thp_retry;
                                goto out;
                        case -EAGAIN:
-                               if (is_thp)
-                                       thp_retry++;
-                               else if (!no_subpage_counting)
+                               if (is_large) {
+                                       large_retry++;
+                                       thp_retry += is_thp;
+                               } else if (!no_split_folio_counting) {
                                        retry++;
-                               nr_retry_pages += nr_subpages;
+                               }
+                               nr_retry_pages += nr_pages;
                                break;
                        case MIGRATEPAGE_SUCCESS:
-                               nr_succeeded += nr_subpages;
-                               if (is_thp)
-                                       nr_thp_succeeded++;
+                               nr_succeeded += nr_pages;
+                               nr_thp_succeeded += is_thp;
                                break;
                        default:
                                /*
                                 * Permanent failure (-EBUSY, etc.):
-                                * unlike -EAGAIN case, the failed page is
-                                * removed from migration page list and not
+                                * unlike -EAGAIN case, the failed folio is
+                                * removed from migration folio list and not
                                 * retried in the next outer loop.
                                 */
-                               if (is_thp)
-                                       nr_thp_failed++;
-                               else if (!no_subpage_counting)
+                               if (is_large) {
+                                       nr_large_failed++;
+                                       nr_thp_failed += is_thp;
+                               } else if (!no_split_folio_counting) {
                                        nr_failed++;
+                               }
 
-                               nr_failed_pages += nr_subpages;
+                               nr_failed_pages += nr_pages;
                                break;
                        }
                }
        }
        nr_failed += retry;
+       nr_large_failed += large_retry;
        nr_thp_failed += thp_retry;
        nr_failed_pages += nr_retry_pages;
        /*
-        * Try to migrate subpages of fail-to-migrate THPs, no nr_failed
-        * counting in this round, since all subpages of a THP is counted
-        * as 1 failure in the first round.
+        * Try to migrate split folios of fail-to-migrate large folios, no
+        * nr_failed counting in this round, since all split folios of a
+        * large folio is counted as 1 failure in the first round.
         */
-       if (!list_empty(&thp_split_pages)) {
+       if (!list_empty(&split_folios)) {
                /*
-                * Move non-migrated pages (after 10 retries) to ret_pages
+                * Move non-migrated folios (after 10 retries) to ret_folios
                 * to avoid migrating them again.
                 */
-               list_splice_init(from, &ret_pages);
-               list_splice_init(&thp_split_pages, from);
-               no_subpage_counting = true;
+               list_splice_init(from, &ret_folios);
+               list_splice_init(&split_folios, from);
+               no_split_folio_counting = true;
                retry = 1;
-               goto thp_subpage_migration;
+               goto split_folio_migration;
        }
 
-       rc = nr_failed + nr_thp_failed;
+       rc = nr_failed + nr_large_failed;
 out:
        /*
-        * Put the permanent failure page back to migration list, they
+        * Put the permanent failure folio back to migration list, they
         * will be put back to the right list by the caller.
         */
-       list_splice(&ret_pages, from);
+       list_splice(&ret_folios, from);
 
        /*
-        * Return 0 in case all subpages of fail-to-migrate THPs are
-        * migrated successfully.
+        * Return 0 in case all split folios of fail-to-migrate large folios
+        * are migrated successfully.
         */
        if (list_empty(from))
                rc = 0;