diff options
| -rw-r--r-- | include/linux/writeback.h | 3 | ||||
| -rw-r--r-- | mm/shmem.c | 28 | ||||
| -rw-r--r-- | mm/vmscan.c | 30 |
3 files changed, 48 insertions, 13 deletions
diff --git a/include/linux/writeback.h b/include/linux/writeback.h index 1a54676d843a..51278327b3c6 100644 --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -79,6 +79,9 @@ struct writeback_control { */ struct swap_iocb **swap_plug; + /* Target list for splitting a large folio */ + struct list_head *list; + /* internal fields used by the ->writepages implementation: */ struct folio_batch fbatch; pgoff_t index; diff --git a/mm/shmem.c b/mm/shmem.c index 4af6f3ea9c4f..1448a7a9a282 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -795,7 +795,6 @@ static int shmem_add_to_page_cache(struct folio *folio, VM_BUG_ON_FOLIO(index != round_down(index, nr), folio); VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); VM_BUG_ON_FOLIO(!folio_test_swapbacked(folio), folio); - VM_BUG_ON(expected && folio_test_large(folio)); folio_ref_add(folio, nr); folio->mapping = mapping; @@ -1460,6 +1459,7 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) swp_entry_t swap; pgoff_t index; int nr_pages; + bool split = false; /* * Our capabilities prevent regular writeback or sync from ever calling @@ -1478,14 +1478,26 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) goto redirty; /* - * If /sys/kernel/mm/transparent_hugepage/shmem_enabled is "always" or - * "force", drivers/gpu/drm/i915/gem/i915_gem_shmem.c gets huge pages, - * and its shmem_writeback() needs them to be split when swapping. + * If CONFIG_THP_SWAP is not enabled, the large folio should be + * split when swapping. + * + * And shrinkage of pages beyond i_size does not split swap, so + * swapout of a large folio crossing i_size needs to split too + * (unless fallocate has been used to preallocate beyond EOF). */ if (folio_test_large(folio)) { + index = shmem_fallocend(inode, + DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE)); + if ((index > folio->index && index < folio_next_index(folio)) || + !IS_ENABLED(CONFIG_THP_SWAP)) + split = true; + } + + if (split) { +try_split: /* Ensure the subpages are still dirty */ folio_test_set_dirty(folio); - if (split_huge_page(page) < 0) + if (split_huge_page_to_list_to_order(page, wbc->list, 0)) goto redirty; folio = page_folio(page); folio_clear_dirty(folio); @@ -1527,8 +1539,12 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc) } swap = folio_alloc_swap(folio); - if (!swap.val) + if (!swap.val) { + if (nr_pages > 1) + goto try_split; + goto redirty; + } /* * Add inode to shmem_unuse()'s list of swapped-out inodes, diff --git a/mm/vmscan.c b/mm/vmscan.c index 243b62b9f89d..1b6542aaf81e 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -628,7 +628,7 @@ typedef enum { * Calls ->writepage(). */ static pageout_t pageout(struct folio *folio, struct address_space *mapping, - struct swap_iocb **plug) + struct swap_iocb **plug, struct list_head *folio_list) { /* * If the folio is dirty, only perform writeback if that write @@ -676,6 +676,14 @@ static pageout_t pageout(struct folio *folio, struct address_space *mapping, .swap_plug = plug, }; + /* + * The large shmem folio can be split if CONFIG_THP_SWAP is + * not enabled or contiguous swap entries are failed to + * allocate. + */ + if (shmem_mapping(mapping) && folio_test_large(folio)) + wbc.list = folio_list; + folio_set_reclaim(folio); res = mapping->a_ops->writepage(&folio->page, &wbc); if (res < 0) @@ -1257,11 +1265,6 @@ retry: goto activate_locked_split; } } - } else if (folio_test_swapbacked(folio) && - folio_test_large(folio)) { - /* Split shmem folio */ - if (split_folio_to_list(folio, folio_list)) - goto keep_locked; } /* @@ -1362,12 +1365,25 @@ retry: * starts and then write it out here. */ try_to_unmap_flush_dirty(); - switch (pageout(folio, mapping, &plug)) { + switch (pageout(folio, mapping, &plug, folio_list)) { case PAGE_KEEP: goto keep_locked; case PAGE_ACTIVATE: + /* + * If shmem folio is split when writeback to swap, + * the tail pages will make their own pass through + * this function and be accounted then. + */ + if (nr_pages > 1 && !folio_test_large(folio)) { + sc->nr_scanned -= (nr_pages - 1); + nr_pages = 1; + } goto activate_locked; case PAGE_SUCCESS: + if (nr_pages > 1 && !folio_test_large(folio)) { + sc->nr_scanned -= (nr_pages - 1); + nr_pages = 1; + } stat->nr_pageout += nr_pages; if (folio_test_writeback(folio)) |