On Tue, 14 Feb 2023 21:59:29 +0800 Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx> wrote: > 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 Reviewed-by: SeongJae Park <sj@xxxxxxxxxx> Thanks, SJ
