From: Kairui Song Only __folio_freeze_split_anon() sees anon folios and swap cache folios now. The file split helper only handles page cache folios, which hold exactly folio_nr_pages() references. Rename folio_cache_ref_count() to folio_swapcache_ref_count() and drop the anon check so the helper counts what its name says. The file split helper now uses folio_nr_pages() directly. No feature change. Reviewed-by: Zi Yan Reviewed-by: Yeoreum Yun Reviewed-by: Kiryl Shutsemau (Meta) Signed-off-by: Kairui Song --- mm/huge_memory.c | 35 +++++++++++++++-------------------- 1 file changed, 15 insertions(+), 20 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index ea8bcace028d..fc4dc3f9b563 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -3994,10 +3994,10 @@ int folio_check_splittable(struct folio *folio, unsigned int new_order, return 0; } -/* Number of folio references from the pagecache or the swapcache. */ -static unsigned int folio_cache_ref_count(const struct folio *folio) +/* Number of folio references from the swapcache. */ +static unsigned int folio_swapcache_ref_count(const struct folio *folio) { - if (folio_test_anon(folio) && !folio_test_swapcache(folio)) + if (!folio_test_swapcache(folio)) return 0; return folio_nr_pages(folio); } @@ -4065,7 +4065,7 @@ static int __folio_freeze_split_anon(struct folio *folio, local_irq_disable(); - if (!folio_ref_freeze(folio, folio_cache_ref_count(folio) + 1)) { + if (!folio_ref_freeze(folio, folio_swapcache_ref_count(folio) + 1)) { ret = -EAGAIN; goto out_no_split; } @@ -4102,7 +4102,7 @@ static int __folio_freeze_split_anon(struct folio *folio, next = folio_next(new_folio); zone_device_private_split_cb(folio, new_folio); folio_ref_unfreeze(new_folio, - folio_cache_ref_count(new_folio) + 1); + folio_swapcache_ref_count(new_folio) + 1); if (do_lru) lru_add_split_folio(folio, new_folio, lruvec, list); if (ci) @@ -4110,7 +4110,7 @@ static int __folio_freeze_split_anon(struct folio *folio, } zone_device_private_split_cb(folio, NULL); - folio_ref_unfreeze(folio, folio_cache_ref_count(folio) + 1); + folio_ref_unfreeze(folio, folio_swapcache_ref_count(folio) + 1); if (do_lru) lruvec_unlock(lruvec); @@ -4139,6 +4139,7 @@ static int __folio_freeze_split_file(struct folio *folio, struct address_space *mapping = folio->mapping; XA_STATE(xas, &mapping->i_pages, folio->index); struct folio *end_folio = folio_next(folio); + long old_nr_pages = folio_nr_pages(folio); struct mem_cgroup *memcg, *old_memcg; struct folio *new_folio, *next; int nr_shmem_dropped = 0; @@ -4209,22 +4210,16 @@ static int __folio_freeze_split_file(struct folio *folio, goto fail; } - if (!folio_ref_freeze(folio, folio_cache_ref_count(folio) + 1)) { + if (!folio_ref_freeze(folio, old_nr_pages + 1)) { ret = -EAGAIN; goto fail; } - if (folio_test_pmd_mappable(folio) && - new_order < HPAGE_PMD_ORDER) { - int nr = folio_nr_pages(folio); - - if (folio_test_swapbacked(folio)) { - lruvec_stat_mod_folio(folio, - NR_SHMEM_THPS, -nr); - } else { - lruvec_stat_mod_folio(folio, - NR_FILE_THPS, -nr); - } + if (folio_test_pmd_mappable(folio) && new_order < HPAGE_PMD_ORDER) { + if (folio_test_swapbacked(folio)) + lruvec_stat_mod_folio(folio, NR_SHMEM_THPS, -old_nr_pages); + else + lruvec_stat_mod_folio(folio, NR_FILE_THPS, -old_nr_pages); } /* lock lru list/PageCompound, ref frozen by page_ref_freeze */ @@ -4248,7 +4243,7 @@ static int __folio_freeze_split_file(struct folio *folio, next = folio_next(new_folio); folio_ref_unfreeze(new_folio, - folio_cache_ref_count(new_folio) + 1); + folio_nr_pages(new_folio) + 1); lru_add_split_folio(folio, new_folio, lruvec, list); @@ -4275,7 +4270,7 @@ static int __folio_freeze_split_file(struct folio *folio, * Otherwise, a parallel folio_try_get() can grab @folio * and its caller can see stale page cache entries. */ - folio_ref_unfreeze(folio, folio_cache_ref_count(folio) + 1); + folio_ref_unfreeze(folio, folio_nr_pages(folio) + 1); lruvec_unlock(lruvec); fail: /* -- 2.55.0