1 // SPDX-License-Identifier: GPL-2.0-only
10  * Linux VM subsystem. Fine-tuning documentation can be found in
11  * Documentation/admin-guide/sysctl/vm.rst.
32 #include <linux/backing-dev.h>
84  * This path almost never happens for VM activity - pages are normally freed
85  * in batches.  But it gets used by networking - and for compound pages.
112 	free_unref_page(&folio->page, folio_order(folio));  in __folio_put()
117  * put_pages_list() - release a list of pages
118  * @pages: list of pages threaded on page->lru
174 		 * folio->mlock_count = !!folio_test_mlocked(folio)?  in lru_add()
180 		folio->mlock_count = 0;  in lru_add()
196 		struct folio *folio = fbatch->folios[i];  in folio_batch_move_lru()
274 	unsigned long cost;  in lru_note_cost()  local
277 	 * Reflect the relative cost of incurring IO and spending CPU  in lru_note_cost()
283 	cost = nr_io * SWAP_CLUSTER_MAX + nr_rotated;  in lru_note_cost()
289 		 * Hold lruvec->lru_lock is safe here, since  in lru_note_cost()
291 		 * 2) From a pre-LRU page during refault (which also holds the  in lru_note_cost()
295 		spin_lock_irq(&lruvec->lru_lock);  in lru_note_cost()
296 		/* Record cost event */  in lru_note_cost()
298 			lruvec->file_cost += cost;  in lru_note_cost()
300 			lruvec->anon_cost += cost;  in lru_note_cost()
315 		if (lruvec->file_cost + lruvec->anon_cost > lrusize / 4) {  in lru_note_cost()
316 			lruvec->file_cost /= 2;  in lru_note_cost()
317 			lruvec->anon_cost /= 2;  in lru_note_cost()
319 		spin_unlock_irq(&lruvec->lru_lock);  in lru_note_cost()
400 	for (i = folio_batch_count(fbatch) - 1; i >= 0; i--) {  in __lru_cache_activate_folio()
401 		struct folio *batch_folio = fbatch->folios[i];  in __lru_cache_activate_folio()
415 	unsigned long new_flags, old_flags = READ_ONCE(folio->flags);  in folio_inc_refs()
438 	} while (!try_cmpxchg(&folio->flags, &old_flags, new_flags));  in folio_inc_refs()
447  * folio_mark_accessed - Mark a folio as having seen activity.
452  * * inactive,unreferenced	->	inactive,referenced
453  * * inactive,referenced	->	active,unreferenced
454  * * active,unreferenced	->	active,referenced
456  * When a newly allocated folio is not yet visible, so safe for non-atomic ops,
494  * folio_add_lru - Add a folio to an LRU list.
510 	    lru_gen_in_fault() && !(current->flags & PF_MEMALLOC))  in folio_add_lru()
518  * folio_add_lru_vma() - Add a folio to the appropate LRU list for this VMA.
529 	if (unlikely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) == VM_LOCKED))  in folio_add_lru_vma()
540  * effective than the single-page writeout from reclaim.
545  * 1. active, mapped folio -> none
546  * 2. active, dirty/writeback folio -> inactive, head, reclaim
547  * 3. inactive, mapped folio -> none
548  * 4. inactive, dirty/writeback folio -> inactive, head, reclaim
549  * 5. inactive, clean -> inactive, tail
550  * 6. Others -> none
554  * than the single-page writeout from reclaim.
639  * disabled; or "cpu" is being hot-unplugged, and is already dead.
644 	struct folio_batch *fbatch = &fbatches->lru_add;  in lru_add_drain_cpu()
649 	fbatch = &fbatches->lru_move_tail;  in lru_add_drain_cpu()
660 	fbatch = &fbatches->lru_deactivate_file;  in lru_add_drain_cpu()
664 	fbatch = &fbatches->lru_deactivate;  in lru_add_drain_cpu()
668 	fbatch = &fbatches->lru_lazyfree;  in lru_add_drain_cpu()
676  * deactivate_file_folio() - Deactivate a file folio.
695  * folio_deactivate - deactivate a folio
711  * folio_mark_lazyfree - make an anon folio lazyfree
735  * It's called from per-cpu workqueue context in SMP case so
772 	return folio_batch_count(&fbatches->lru_add) ||  in cpu_needs_drain()
773 		folio_batch_count(&fbatches->lru_move_tail) ||  in cpu_needs_drain()
774 		folio_batch_count(&fbatches->lru_deactivate_file) ||  in cpu_needs_drain()
775 		folio_batch_count(&fbatches->lru_deactivate) ||  in cpu_needs_drain()
776 		folio_batch_count(&fbatches->lru_lazyfree) ||  in cpu_needs_drain()
777 		folio_batch_count(&fbatches->lru_activate) ||  in cpu_needs_drain()
783  * Doesn't need any cpu hotplug locking because we do rely on per-cpu
792 	 * lru_drain_gen - Global pages generation number  in __lru_add_drain_all()
797 	 * This is an optimization for the highly-contended use case where a  in __lru_add_drain_all()
851 	 * below and has already reached CPU #y's per-cpu data. CPU #x comes  in __lru_add_drain_all()
852 	 * along, adds some pages to its per-cpu vectors, then calls  in __lru_add_drain_all()
926  * folios_put_refs - Reduce the reference count on a batch of folios.
946 	for (i = 0, j = 0; i < folios->nr; i++) {  in folios_put_refs()
947 		struct folio *folio = folios->folios[i];  in folios_put_refs()
981 			folios->folios[j] = folio;  in folios_put_refs()
991 	folios->nr = j;  in folios_put_refs()
998  * release_pages - batched put_page()
1021 		/* Is our next entry actually "nr_pages" -> "nr_refs" ? */  in release_pages()
1038  * The folios which we're about to release may be in the deferred lru-addition
1040  * OK from a correctness point of view but is inefficient - those folios may be
1041  * cache-warm and we want to give them back to the page allocator ASAP.
1049 	if (!fbatch->percpu_pvec_drained) {  in __folio_batch_release()
1051 		fbatch->percpu_pvec_drained = true;  in __folio_batch_release()
1058  * folio_batch_remove_exceptionals() - Prune non-folios from a batch.
1062  * entries.  This function prunes all the non-folio entries from @fbatch
1063  * without leaving holes, so that it can be passed on to folio-only batch
1071 		struct folio *folio = fbatch->folios[i];  in folio_batch_remove_exceptionals()
1073 			fbatch->folios[j++] = folio;  in folio_batch_remove_exceptionals()
1075 	fbatch->nr = j;  in folio_batch_remove_exceptionals()
1083 	unsigned long megs = totalram_pages() >> (20 - PAGE_SHIFT);  in swap_setup()
1085 	/* Use a smaller cluster for small-memory machines */  in swap_setup()