From 94ac2ab3fff96814d7460a27a0e9d004abbd4128 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Wed, 19 Jun 2024 23:00:37 +0200 Subject: Merging upstream version 6.9.2. Signed-off-by: Daniel Baumann --- mm/swap.c | 197 ++++++++++++++++++++++++++++++++++++-------------------------- 1 file changed, 114 insertions(+), 83 deletions(-) (limited to 'mm/swap.c') diff --git a/mm/swap.c b/mm/swap.c index cd8f0150b..500a09a48 100644 --- a/mm/swap.c +++ b/mm/swap.c @@ -74,22 +74,21 @@ static DEFINE_PER_CPU(struct cpu_fbatches, cpu_fbatches) = { .lock = INIT_LOCAL_LOCK(lock), }; -/* - * This path almost never happens for VM activity - pages are normally freed - * in batches. But it gets used by networking - and for compound pages. - */ -static void __page_cache_release(struct folio *folio) +static void __page_cache_release(struct folio *folio, struct lruvec **lruvecp, + unsigned long *flagsp) { if (folio_test_lru(folio)) { - struct lruvec *lruvec; - unsigned long flags; - - lruvec = folio_lruvec_lock_irqsave(folio, &flags); - lruvec_del_folio(lruvec, folio); + folio_lruvec_relock_irqsave(folio, lruvecp, flagsp); + lruvec_del_folio(*lruvecp, folio); __folio_clear_lru_flags(folio); - unlock_page_lruvec_irqrestore(lruvec, flags); } - /* See comment on folio_test_mlocked in release_pages() */ + + /* + * In rare cases, when truncation or holepunching raced with + * munlock after VM_LOCKED was cleared, Mlocked may still be + * found set here. This does not indicate a problem, unless + * "unevictable_pgs_cleared" appears worryingly large. + */ if (unlikely(folio_test_mlocked(folio))) { long nr_pages = folio_nr_pages(folio); @@ -99,9 +98,23 @@ static void __page_cache_release(struct folio *folio) } } +/* + * This path almost never happens for VM activity - pages are normally freed + * in batches. But it gets used by networking - and for compound pages. + */ +static void page_cache_release(struct folio *folio) +{ + struct lruvec *lruvec = NULL; + unsigned long flags; + + __page_cache_release(folio, &lruvec, &flags); + if (lruvec) + unlock_page_lruvec_irqrestore(lruvec, flags); +} + static void __folio_put_small(struct folio *folio) { - __page_cache_release(folio); + page_cache_release(folio); mem_cgroup_uncharge(folio); free_unref_page(&folio->page, 0); } @@ -115,7 +128,7 @@ static void __folio_put_large(struct folio *folio) * be called for hugetlb (it has a separate hugetlb_cgroup.) */ if (!folio_test_hugetlb(folio)) - __page_cache_release(folio); + page_cache_release(folio); destroy_large_folio(folio); } @@ -138,22 +151,25 @@ EXPORT_SYMBOL(__folio_put); */ void put_pages_list(struct list_head *pages) { + struct folio_batch fbatch; struct folio *folio, *next; + folio_batch_init(&fbatch); list_for_each_entry_safe(folio, next, pages, lru) { - if (!folio_put_testzero(folio)) { - list_del(&folio->lru); + if (!folio_put_testzero(folio)) continue; - } if (folio_test_large(folio)) { - list_del(&folio->lru); __folio_put_large(folio); continue; } /* LRU flag must be clear because it's passed using the lru */ + if (folio_batch_add(&fbatch, folio) > 0) + continue; + free_unref_folios(&fbatch); } - free_unref_page_list(pages); + if (fbatch.nr) + free_unref_folios(&fbatch); INIT_LIST_HEAD(pages); } EXPORT_SYMBOL(put_pages_list); @@ -175,7 +191,7 @@ static void lru_add_fn(struct lruvec *lruvec, struct folio *folio) * while the LRU lock is held. * * (That is not true of __page_cache_release(), and not necessarily - * true of release_pages(): but those only clear the mlocked flag after + * true of folios_put(): but those only clear the mlocked flag after * folio_put_testzero() has excluded any other users of the folio.) */ if (folio_evictable(folio)) { @@ -213,7 +229,7 @@ static void folio_batch_move_lru(struct folio_batch *fbatch, move_fn_t move_fn) if (move_fn != lru_add_fn && !folio_test_clear_lru(folio)) continue; - lruvec = folio_lruvec_relock_irqsave(folio, lruvec, &flags); + folio_lruvec_relock_irqsave(folio, &lruvec, &flags); move_fn(lruvec, folio); folio_set_lru(folio); @@ -221,8 +237,7 @@ static void folio_batch_move_lru(struct folio_batch *fbatch, move_fn_t move_fn) if (lruvec) unlock_page_lruvec_irqrestore(lruvec, flags); - folios_put(fbatch->folios, folio_batch_count(fbatch)); - folio_batch_reinit(fbatch); + folios_put(fbatch); } static void folio_batch_add_and_move(struct folio_batch *fbatch, @@ -946,41 +961,29 @@ void lru_cache_disable(void) } /** - * release_pages - batched put_page() - * @arg: array of pages to release - * @nr: number of pages + * folios_put_refs - Reduce the reference count on a batch of folios. + * @folios: The folios. + * @refs: The number of refs to subtract from each folio. * - * Decrement the reference count on all the pages in @arg. If it - * fell to zero, remove the page from the LRU and free it. + * Like folio_put(), but for a batch of folios. This is more efficient + * than writing the loop yourself as it will optimise the locks which need + * to be taken if the folios are freed. The folios batch is returned + * empty and ready to be reused for another batch; there is no need + * to reinitialise it. If @refs is NULL, we subtract one from each + * folio refcount. * - * Note that the argument can be an array of pages, encoded pages, - * or folio pointers. We ignore any encoded bits, and turn any of - * them into just a folio that gets free'd. + * Context: May be called in process or interrupt context, but not in NMI + * context. May be called while holding a spinlock. */ -void release_pages(release_pages_arg arg, int nr) +void folios_put_refs(struct folio_batch *folios, unsigned int *refs) { - int i; - struct encoded_page **encoded = arg.encoded_pages; - LIST_HEAD(pages_to_free); + int i, j; struct lruvec *lruvec = NULL; unsigned long flags = 0; - unsigned int lock_batch; - for (i = 0; i < nr; i++) { - struct folio *folio; - - /* Turn any of the argument types into a folio */ - folio = page_folio(encoded_page_ptr(encoded[i])); - - /* - * Make sure the IRQ-safe lock-holding time does not get - * excessive with a continuous string of pages from the - * same lruvec. The lock is held only if lruvec != NULL. - */ - if (lruvec && ++lock_batch == SWAP_CLUSTER_MAX) { - unlock_page_lruvec_irqrestore(lruvec, flags); - lruvec = NULL; - } + for (i = 0, j = 0; i < folios->nr; i++) { + struct folio *folio = folios->folios[i]; + unsigned int nr_refs = refs ? refs[i] : 1; if (is_huge_zero_page(&folio->page)) continue; @@ -990,56 +993,85 @@ void release_pages(release_pages_arg arg, int nr) unlock_page_lruvec_irqrestore(lruvec, flags); lruvec = NULL; } - if (put_devmap_managed_page(&folio->page)) + if (put_devmap_managed_page_refs(&folio->page, nr_refs)) continue; - if (folio_put_testzero(folio)) + if (folio_ref_sub_and_test(folio, nr_refs)) free_zone_device_page(&folio->page); continue; } - if (!folio_put_testzero(folio)) + if (!folio_ref_sub_and_test(folio, nr_refs)) continue; - if (folio_test_large(folio)) { + /* hugetlb has its own memcg */ + if (folio_test_hugetlb(folio)) { if (lruvec) { unlock_page_lruvec_irqrestore(lruvec, flags); lruvec = NULL; } - __folio_put_large(folio); + free_huge_folio(folio); continue; } + if (folio_test_large(folio) && + folio_test_large_rmappable(folio)) + folio_undo_large_rmappable(folio); - if (folio_test_lru(folio)) { - struct lruvec *prev_lruvec = lruvec; + __page_cache_release(folio, &lruvec, &flags); - lruvec = folio_lruvec_relock_irqsave(folio, lruvec, - &flags); - if (prev_lruvec != lruvec) - lock_batch = 0; + if (j != i) + folios->folios[j] = folio; + j++; + } + if (lruvec) + unlock_page_lruvec_irqrestore(lruvec, flags); + if (!j) { + folio_batch_reinit(folios); + return; + } - lruvec_del_folio(lruvec, folio); - __folio_clear_lru_flags(folio); - } + folios->nr = j; + mem_cgroup_uncharge_folios(folios); + free_unref_folios(folios); +} +EXPORT_SYMBOL(folios_put_refs); - /* - * In rare cases, when truncation or holepunching raced with - * munlock after VM_LOCKED was cleared, Mlocked may still be - * found set here. This does not indicate a problem, unless - * "unevictable_pgs_cleared" appears worryingly large. - */ - if (unlikely(folio_test_mlocked(folio))) { - __folio_clear_mlocked(folio); - zone_stat_sub_folio(folio, NR_MLOCK); - count_vm_event(UNEVICTABLE_PGCLEARED); - } +/** + * release_pages - batched put_page() + * @arg: array of pages to release + * @nr: number of pages + * + * Decrement the reference count on all the pages in @arg. If it + * fell to zero, remove the page from the LRU and free it. + * + * Note that the argument can be an array of pages, encoded pages, + * or folio pointers. We ignore any encoded bits, and turn any of + * them into just a folio that gets free'd. + */ +void release_pages(release_pages_arg arg, int nr) +{ + struct folio_batch fbatch; + int refs[PAGEVEC_SIZE]; + struct encoded_page **encoded = arg.encoded_pages; + int i; + + folio_batch_init(&fbatch); + for (i = 0; i < nr; i++) { + /* Turn any of the argument types into a folio */ + struct folio *folio = page_folio(encoded_page_ptr(encoded[i])); + + /* Is our next entry actually "nr_pages" -> "nr_refs" ? */ + refs[fbatch.nr] = 1; + if (unlikely(encoded_page_flags(encoded[i]) & + ENCODED_PAGE_BIT_NR_PAGES_NEXT)) + refs[fbatch.nr] = encoded_nr_pages(encoded[++i]); - list_add(&folio->lru, &pages_to_free); + if (folio_batch_add(&fbatch, folio) > 0) + continue; + folios_put_refs(&fbatch, refs); } - if (lruvec) - unlock_page_lruvec_irqrestore(lruvec, flags); - mem_cgroup_uncharge_list(&pages_to_free); - free_unref_page_list(&pages_to_free); + if (fbatch.nr) + folios_put_refs(&fbatch, refs); } EXPORT_SYMBOL(release_pages); @@ -1059,8 +1091,7 @@ void __folio_batch_release(struct folio_batch *fbatch) lru_add_drain(); fbatch->percpu_pvec_drained = true; } - release_pages(fbatch->folios, folio_batch_count(fbatch)); - folio_batch_reinit(fbatch); + folios_put(fbatch); } EXPORT_SYMBOL(__folio_batch_release); -- cgit v1.2.3