Now the folio_isolate_lru() did not return a boolean value to indicate isolation success or not, however below code checking the return value can make people think that it was a boolean success/failure thing, which makes people easy to make mistakes (see the fix patch[1]). if (folio_isolate_lru(folio)) continue; Thus it's better to check the negative error value expilictly returned by folio_isolate_lru(), which makes code more clear per Linus's suggestion[2]. Moreover Matthew suggested we can convert the isolation functions to return a boolean[3], since most users did not care about the negative error value, and can also remove the confusing of checking return value. So this patch converts the folio_isolate_lru() to return a boolean value, which means return 'true' to indicate the folio isolation is successful, and 'false' means a failure to isolation. Meanwhile changing all users' logic of checking the isolation state. No functional changes intended. [1] https://lore.kernel.org/all/20230131063206.28820-1-Kuan-Ying.Lee@xxxxxxxxxxxx/T/#u [2] https://lore.kernel.org/all/CAHk-=wiBrY+O-4=2mrbVyxR+hOqfdJ=Do6xoucfJ9_5az01L4Q@xxxxxxxxxxxxxx/ [3] https://lore.kernel.org/all/Y+sTFqwMNAjDvxw3@xxxxxxxxxxxxxxxxxxxx/ Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> --- mm/damon/paddr.c | 2 +- mm/folio-compat.c | 8 +++++++- mm/gup.c | 2 +- mm/internal.h | 2 +- mm/khugepaged.c | 2 +- mm/madvise.c | 4 ++-- mm/mempolicy.c | 2 +- mm/vmscan.c | 10 +++++----- 8 files changed, 19 insertions(+), 13 deletions(-) diff --git a/mm/damon/paddr.c b/mm/damon/paddr.c index b4df9b9bcc0a..607bb69e526c 100644 --- a/mm/damon/paddr.c +++ b/mm/damon/paddr.c @@ -246,7 +246,7 @@ static unsigned long damon_pa_pageout(struct damon_region *r, struct damos *s) folio_clear_referenced(folio); folio_test_clear_young(folio); - if (folio_isolate_lru(folio)) { + if (!folio_isolate_lru(folio)) { folio_put(folio); continue; } diff --git a/mm/folio-compat.c b/mm/folio-compat.c index 18c48b557926..540373cf904e 100644 --- a/mm/folio-compat.c +++ b/mm/folio-compat.c @@ -115,9 +115,15 @@ EXPORT_SYMBOL(grab_cache_page_write_begin); int isolate_lru_page(struct page *page) { + bool ret; + if (WARN_RATELIMIT(PageTail(page), "trying to isolate tail page")) return -EBUSY; - return folio_isolate_lru((struct folio *)page); + ret = folio_isolate_lru((struct folio *)page); + if (ret) + return 0; + + return -EBUSY; } void putback_lru_page(struct page *page) diff --git a/mm/gup.c b/mm/gup.c index b0885f70579c..eab18ba045db 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -1939,7 +1939,7 @@ static unsigned long collect_longterm_unpinnable_pages( drain_allow = false; } - if (folio_isolate_lru(folio)) + if (!folio_isolate_lru(folio)) continue; list_add_tail(&folio->lru, movable_page_list); diff --git a/mm/internal.h b/mm/internal.h index dfb37e94e140..8645e8496537 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -188,7 +188,7 @@ pgprot_t __init early_memremap_pgprot_adjust(resource_size_t phys_addr, * in mm/vmscan.c: */ int isolate_lru_page(struct page *page); -int folio_isolate_lru(struct folio *folio); +bool folio_isolate_lru(struct folio *folio); void putback_lru_page(struct page *page); void folio_putback_lru(struct folio *folio); extern void reclaim_throttle(pg_data_t *pgdat, enum vmscan_throttle_state reason); diff --git a/mm/khugepaged.c b/mm/khugepaged.c index a5d32231bfad..cee659cfa3c1 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -2047,7 +2047,7 @@ static int collapse_file(struct mm_struct *mm, unsigned long addr, goto out_unlock; } - if (folio_isolate_lru(folio)) { + if (!folio_isolate_lru(folio)) { result = SCAN_DEL_PAGE_LRU; goto out_unlock; } diff --git a/mm/madvise.c b/mm/madvise.c index 5a5a687d03c2..c2202f51e9dd 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -406,7 +406,7 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd, folio_clear_referenced(folio); folio_test_clear_young(folio); if (pageout) { - if (!folio_isolate_lru(folio)) { + if (folio_isolate_lru(folio)) { if (folio_test_unevictable(folio)) folio_putback_lru(folio); else @@ -500,7 +500,7 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd, folio_clear_referenced(folio); folio_test_clear_young(folio); if (pageout) { - if (!folio_isolate_lru(folio)) { + if (folio_isolate_lru(folio)) { if (folio_test_unevictable(folio)) folio_putback_lru(folio); else diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 0919c7a719d4..2751bc3310fd 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1033,7 +1033,7 @@ static int migrate_folio_add(struct folio *folio, struct list_head *foliolist, * expensive, so check the estimated mapcount of the folio instead. */ if ((flags & MPOL_MF_MOVE_ALL) || folio_estimated_sharers(folio) == 1) { - if (!folio_isolate_lru(folio)) { + if (folio_isolate_lru(folio)) { list_add_tail(&folio->lru, foliolist); node_stat_mod_folio(folio, NR_ISOLATED_ANON + folio_is_file_lru(folio), diff --git a/mm/vmscan.c b/mm/vmscan.c index 34535bbd4fe9..7658b40df947 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -2337,12 +2337,12 @@ static unsigned long isolate_lru_folios(unsigned long nr_to_scan, * (2) The lru_lock must not be held. * (3) Interrupts must be enabled. * - * Return: 0 if the folio was removed from an LRU list. - * -EBUSY if the folio was not on an LRU list. + * Return: true if the folio was removed from an LRU list. + * false if the folio was not on an LRU list. */ -int folio_isolate_lru(struct folio *folio) +bool folio_isolate_lru(struct folio *folio) { - int ret = -EBUSY; + bool ret = false; VM_BUG_ON_FOLIO(!folio_ref_count(folio), folio); @@ -2353,7 +2353,7 @@ int folio_isolate_lru(struct folio *folio) lruvec = folio_lruvec_lock_irq(folio); lruvec_del_folio(lruvec, folio); unlock_page_lruvec_irq(lruvec); - ret = 0; + ret = true; } return ret; -- 2.27.0
