diff options
Diffstat (limited to 'mm/filemap.c')
| -rw-r--r-- | mm/filemap.c | 567 |
1 files changed, 272 insertions, 295 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index dae481293b5d..3e9feb5cc570 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -835,6 +835,8 @@ EXPORT_SYMBOL(file_write_and_wait_range); */ void replace_page_cache_page(struct page *old, struct page *new) { + struct folio *fold = page_folio(old); + struct folio *fnew = page_folio(new); struct address_space *mapping = old->mapping; void (*freepage)(struct page *) = mapping->a_ops->freepage; pgoff_t offset = old->index; @@ -848,7 +850,7 @@ void replace_page_cache_page(struct page *old, struct page *new) new->mapping = mapping; new->index = offset; - mem_cgroup_migrate(old, new); + mem_cgroup_migrate(fold, fnew); xas_lock_irq(&xas); xas_store(&xas, new); @@ -870,26 +872,25 @@ void replace_page_cache_page(struct page *old, struct page *new) } EXPORT_SYMBOL_GPL(replace_page_cache_page); -noinline int __add_to_page_cache_locked(struct page *page, - struct address_space *mapping, - pgoff_t offset, gfp_t gfp, - void **shadowp) +noinline int __filemap_add_folio(struct address_space *mapping, + struct folio *folio, pgoff_t index, gfp_t gfp, void **shadowp) { - XA_STATE(xas, &mapping->i_pages, offset); - int huge = PageHuge(page); + XA_STATE(xas, &mapping->i_pages, index); + int huge = folio_test_hugetlb(folio); int error; bool charged = false; - VM_BUG_ON_PAGE(!PageLocked(page), page); - VM_BUG_ON_PAGE(PageSwapBacked(page), page); + VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); + VM_BUG_ON_FOLIO(folio_test_swapbacked(folio), folio); mapping_set_update(&xas, mapping); - get_page(page); - page->mapping = mapping; - page->index = offset; + folio_get(folio); + folio->mapping = mapping; + folio->index = index; if (!huge) { - error = mem_cgroup_charge(page, NULL, gfp); + error = mem_cgroup_charge(folio, NULL, gfp); + VM_BUG_ON_FOLIO(index & (folio_nr_pages(folio) - 1), folio); if (error) goto error; charged = true; @@ -901,7 +902,7 @@ noinline int __add_to_page_cache_locked(struct page *page, unsigned int order = xa_get_order(xas.xa, xas.xa_index); void *entry, *old = NULL; - if (order > thp_order(page)) + if (order > folio_order(folio)) xas_split_alloc(&xas, xa_load(xas.xa, xas.xa_index), order, gfp); xas_lock_irq(&xas); @@ -918,13 +919,13 @@ noinline int __add_to_page_cache_locked(struct page *page, *shadowp = old; /* entry may have been split before we acquired lock */ order = xa_get_order(xas.xa, xas.xa_index); - if (order > thp_order(page)) { + if (order > folio_order(folio)) { xas_split(&xas, old, order); xas_reset(&xas); } } - xas_store(&xas, page); + xas_store(&xas, folio); if (xas_error(&xas)) goto unlock; @@ -932,7 +933,7 @@ noinline int __add_to_page_cache_locked(struct page *page, /* hugetlb pages do not participate in page cache accounting */ if (!huge) - __inc_lruvec_page_state(page, NR_FILE_PAGES); + __lruvec_stat_add_folio(folio, NR_FILE_PAGES); unlock: xas_unlock_irq(&xas); } while (xas_nomem(&xas, gfp)); @@ -940,19 +941,19 @@ unlock: if (xas_error(&xas)) { error = xas_error(&xas); if (charged) - mem_cgroup_uncharge(page); + mem_cgroup_uncharge(folio); goto error; } - trace_mm_filemap_add_to_page_cache(page); + trace_mm_filemap_add_to_page_cache(&folio->page); return 0; error: - page->mapping = NULL; + folio->mapping = NULL; /* Leave page->index set: truncation relies upon it */ - put_page(page); + folio_put(folio); return error; } -ALLOW_ERROR_INJECTION(__add_to_page_cache_locked, ERRNO); +ALLOW_ERROR_INJECTION(__filemap_add_folio, ERRNO); /** * add_to_page_cache_locked - add a locked page to the pagecache @@ -969,59 +970,58 @@ ALLOW_ERROR_INJECTION(__add_to_page_cache_locked, ERRNO); int add_to_page_cache_locked(struct page *page, struct address_space *mapping, pgoff_t offset, gfp_t gfp_mask) { - return __add_to_page_cache_locked(page, mapping, offset, + return __filemap_add_folio(mapping, page_folio(page), offset, gfp_mask, NULL); } EXPORT_SYMBOL(add_to_page_cache_locked); -int add_to_page_cache_lru(struct page *page, struct address_space *mapping, - pgoff_t offset, gfp_t gfp_mask) +int filemap_add_folio(struct address_space *mapping, struct folio *folio, + pgoff_t index, gfp_t gfp) { void *shadow = NULL; int ret; - __SetPageLocked(page); - ret = __add_to_page_cache_locked(page, mapping, offset, - gfp_mask, &shadow); + __folio_set_locked(folio); + ret = __filemap_add_folio(mapping, folio, index, gfp, &shadow); if (unlikely(ret)) - __ClearPageLocked(page); + __folio_clear_locked(folio); else { /* - * The page might have been evicted from cache only + * The folio might have been evicted from cache only * recently, in which case it should be activated like - * any other repeatedly accessed page. - * The exception is pages getting rewritten; evicting other + * any other repeatedly accessed folio. + * The exception is folios getting rewritten; evicting other * data from the working set, only to cache data that will * get overwritten with something else, is a waste of memory. */ - WARN_ON_ONCE(PageActive(page)); - if (!(gfp_mask & __GFP_WRITE) && shadow) - workingset_refault(page, shadow); - lru_cache_add(page); + WARN_ON_ONCE(folio_test_active(folio)); + if (!(gfp & __GFP_WRITE) && shadow) + workingset_refault(folio, shadow); + folio_add_lru(folio); } return ret; } -EXPORT_SYMBOL_GPL(add_to_page_cache_lru); +EXPORT_SYMBOL_GPL(filemap_add_folio); #ifdef CONFIG_NUMA -struct page *__page_cache_alloc(gfp_t gfp) +struct folio *filemap_alloc_folio(gfp_t gfp, unsigned int order) { int n; - struct page *page; + struct folio *folio; if (cpuset_do_page_mem_spread()) { unsigned int cpuset_mems_cookie; do { cpuset_mems_cookie = read_mems_allowed_begin(); n = cpuset_mem_spread_node(); - page = __alloc_pages_node(n, gfp, 0); - } while (!page && read_mems_allowed_retry(cpuset_mems_cookie)); + folio = __folio_alloc_node(gfp, order, n); + } while (!folio && read_mems_allowed_retry(cpuset_mems_cookie)); - return page; + return folio; } - return alloc_pages(gfp, 0); + return folio_alloc(gfp, order); } -EXPORT_SYMBOL(__page_cache_alloc); +EXPORT_SYMBOL(filemap_alloc_folio); #endif /* @@ -1074,11 +1074,11 @@ EXPORT_SYMBOL(filemap_invalidate_unlock_two); */ #define PAGE_WAIT_TABLE_BITS 8 #define PAGE_WAIT_TABLE_SIZE (1 << PAGE_WAIT_TABLE_BITS) -static wait_queue_head_t page_wait_table[PAGE_WAIT_TABLE_SIZE] __cacheline_aligned; +static wait_queue_head_t folio_wait_table[PAGE_WAIT_TABLE_SIZE] __cacheline_aligned; -static wait_queue_head_t *page_waitqueue(struct page *page) +static wait_queue_head_t *folio_waitqueue(struct folio *folio) { - return &page_wait_table[hash_ptr(page, PAGE_WAIT_TABLE_BITS)]; + return &folio_wait_table[hash_ptr(folio, PAGE_WAIT_TABLE_BITS)]; } void __init pagecache_init(void) @@ -1086,7 +1086,7 @@ void __init pagecache_init(void) int i; for (i = 0; i < PAGE_WAIT_TABLE_SIZE; i++) - init_waitqueue_head(&page_wait_table[i]); + init_waitqueue_head(&folio_wait_table[i]); page_writeback_init(); } @@ -1141,10 +1141,10 @@ static int wake_page_function(wait_queue_entry_t *wait, unsigned mode, int sync, */ flags = wait->flags; if (flags & WQ_FLAG_EXCLUSIVE) { - if (test_bit(key->bit_nr, &key->page->flags)) + if (test_bit(key->bit_nr, &key->folio->flags)) return -1; if (flags & WQ_FLAG_CUSTOM) { - if (test_and_set_bit(key->bit_nr, &key->page->flags)) + if (test_and_set_bit(key->bit_nr, &key->folio->flags)) return -1; flags |= WQ_FLAG_DONE; } @@ -1157,7 +1157,7 @@ static int wake_page_function(wait_queue_entry_t *wait, unsigned mode, int sync, * * So update the flags atomically, and wake up the waiter * afterwards to avoid any races. This store-release pairs - * with the load-acquire in wait_on_page_bit_common(). + * with the load-acquire in folio_wait_bit_common(). */ smp_store_release(&wait->flags, flags | WQ_FLAG_WOKEN); wake_up_state(wait->private, mode); @@ -1176,14 +1176,14 @@ static int wake_page_function(wait_queue_entry_t *wait, unsigned mode, int sync, return (flags & WQ_FLAG_EXCLUSIVE) != 0; } -static void wake_up_page_bit(struct page *page, int bit_nr) +static void folio_wake_bit(struct folio *folio, int bit_nr) { - wait_queue_head_t *q = page_waitqueue(page); + wait_queue_head_t *q = folio_waitqueue(folio); struct wait_page_key key; unsigned long flags; wait_queue_entry_t bookmark; - key.page = page; + key.folio = folio; key.bit_nr = bit_nr; key.page_match = 0; @@ -1218,7 +1218,7 @@ static void wake_up_page_bit(struct page *page, int bit_nr) * page waiters. */ if (!waitqueue_active(q) || !key.page_match) { - ClearPageWaiters(page); + folio_clear_waiters(folio); /* * It's possible to miss clearing Waiters here, when we woke * our page waiters, but the hashed waitqueue has waiters for @@ -1230,19 +1230,19 @@ static void wake_up_page_bit(struct page *page, int bit_nr) spin_unlock_irqrestore(&q->lock, flags); } -static void wake_up_page(struct page *page, int bit) +static void folio_wake(struct folio *folio, int bit) { - if (!PageWaiters(page)) + if (!folio_test_waiters(folio)) return; - wake_up_page_bit(page, bit); + folio_wake_bit(folio, bit); } /* - * A choice of three behaviors for wait_on_page_bit_common(): + * A choice of three behaviors for folio_wait_bit_common(): */ enum behavior { EXCLUSIVE, /* Hold ref to page and take the bit when woken, like - * __lock_page() waiting on then setting PG_locked. + * __folio_lock() waiting on then setting PG_locked. */ SHARED, /* Hold ref to page and check the bit when woken, like * wait_on_page_writeback() waiting on PG_writeback. @@ -1253,16 +1253,16 @@ enum behavior { }; /* - * Attempt to check (or get) the page bit, and mark us done + * Attempt to check (or get) the folio flag, and mark us done * if successful. */ -static inline bool trylock_page_bit_common(struct page *page, int bit_nr, +static inline bool folio_trylock_flag(struct folio *folio, int bit_nr, struct wait_queue_entry *wait) { if (wait->flags & WQ_FLAG_EXCLUSIVE) { - if (test_and_set_bit(bit_nr, &page->flags)) + if (test_and_set_bit(bit_nr, &folio->flags)) return false; - } else if (test_bit(bit_nr, &page->flags)) + } else if (test_bit(bit_nr, &folio->flags)) return false; wait->flags |= WQ_FLAG_WOKEN | WQ_FLAG_DONE; @@ -1272,9 +1272,10 @@ static inline bool trylock_page_bit_common(struct page *page, int bit_nr, /* How many times do we accept lock stealing from under a waiter? */ int sysctl_page_lock_unfairness = 5; -static inline int wait_on_page_bit_common(wait_queue_head_t *q, - struct page *page, int bit_nr, int state, enum behavior behavior) +static inline int folio_wait_bit_common(struct folio *folio, int bit_nr, + int state, enum behavior behavior) { + wait_queue_head_t *q = folio_waitqueue(folio); int unfairness = sysctl_page_lock_unfairness; struct wait_page_queue wait_page; wait_queue_entry_t *wait = &wait_page.wait; @@ -1283,8 +1284,8 @@ static inline int wait_on_page_bit_common(wait_queue_head_t *q, unsigned long pflags; if (bit_nr == PG_locked && - !PageUptodate(page) && PageWorkingset(page)) { - if (!PageSwapBacked(page)) { + !folio_test_uptodate(folio) && folio_test_workingset(folio)) { + if (!folio_test_swapbacked(folio)) { delayacct_thrashing_start(); delayacct = true; } @@ -1294,7 +1295,7 @@ static inline int wait_on_page_bit_common(wait_queue_head_t *q, init_wait(wait); wait->func = wake_page_function; - wait_page.page = page; + wait_page.folio = folio; wait_page.bit_nr = bit_nr; repeat: @@ -1309,7 +1310,7 @@ repeat: * Do one last check whether we can get the * page bit synchronously. * - * Do the SetPageWaiters() marking before that + * Do the folio_set_waiters() marking before that * to let any waker we _just_ missed know they * need to wake us up (otherwise they'll never * even go to the slow case that looks at the @@ -1320,8 +1321,8 @@ repeat: * lock to avoid races. */ spin_lock_irq(&q->lock); - SetPageWaiters(page); - if (!trylock_page_bit_common(page, bit_nr, wait)) + folio_set_waiters(folio); + if (!folio_trylock_flag(folio, bit_nr, wait)) __add_wait_queue_entry_tail(q, wait); spin_unlock_irq(&q->lock); @@ -1331,10 +1332,10 @@ repeat: * see whether the page bit testing has already * been done by the wake function. * - * We can drop our reference to the page. + * We can drop our reference to the folio. */ if (behavior == DROP) - put_page(page); + folio_put(folio); /* * Note that until the "finish_wait()", or until @@ -1371,7 +1372,7 @@ repeat: * * And if that fails, we'll have to retry this all. */ - if (unlikely(test_and_set_bit(bit_nr, &page->flags))) + if (unlikely(test_and_set_bit(bit_nr, folio_flags(folio, 0)))) goto repeat; wait->flags |= WQ_FLAG_DONE; @@ -1380,7 +1381,7 @@ repeat: /* * If a signal happened, this 'finish_wait()' may remove the last - * waiter from the wait-queues, but the PageWaiters bit will remain + * waiter from the wait-queues, but the folio waiters bit will remain * set. That's ok. The next wakeup will take care of it, and trying * to do it here would be difficult and prone to races. */ @@ -1411,19 +1412,17 @@ repeat: return wait->flags & WQ_FLAG_WOKEN ? 0 : -EINTR; } -void wait_on_page_bit(struct page *page, int bit_nr) +void folio_wait_bit(struct folio *folio, int bit_nr) { - wait_queue_head_t *q = page_waitqueue(page); - wait_on_page_bit_common(q, page, bit_nr, TASK_UNINTERRUPTIBLE, SHARED); + folio_wait_bit_common(folio, bit_nr, TASK_UNINTERRUPTIBLE, SHARED); } -EXPORT_SYMBOL(wait_on_page_bit); +EXPORT_SYMBOL(folio_wait_bit); -int wait_on_page_bit_killable(struct page *page, int bit_nr) +int folio_wait_bit_killable(struct folio *folio, int bit_nr) { - wait_queue_head_t *q = page_waitqueue(page); - return wait_on_page_bit_common(q, page, bit_nr, TASK_KILLABLE, SHARED); + return folio_wait_bit_common(folio, bit_nr, TASK_KILLABLE, SHARED); } -EXPORT_SYMBOL(wait_on_page_bit_killable); +EXPORT_SYMBOL(folio_wait_bit_killable); /** * put_and_wait_on_page_locked - Drop a reference and wait for it to be unlocked @@ -1440,31 +1439,28 @@ EXPORT_SYMBOL(wait_on_page_bit_killable); */ int put_and_wait_on_page_locked(struct page *page, int state) { - wait_queue_head_t *q; - - page = compound_head(page); - q = page_waitqueue(page); - return wait_on_page_bit_common(q, page, PG_locked, state, DROP); + return folio_wait_bit_common(page_folio(page), PG_locked, state, + DROP); } /** - * add_page_wait_queue - Add an arbitrary waiter to a page's wait queue - * @page: Page defining the wait queue of interest + * folio_add_wait_queue - Add an arbitrary waiter to a folio's wait queue + * @folio: Folio defining the wait queue of interest * @waiter: Waiter to add to the queue * - * Add an arbitrary @waiter to the wait queue for the nominated @page. + * Add an arbitrary @waiter to the wait queue for the nominated @folio. */ -void add_page_wait_queue(struct page *page, wait_queue_entry_t *waiter) +void folio_add_wait_queue(struct folio *folio, wait_queue_entry_t *waiter) { - wait_queue_head_t *q = page_waitqueue(page); + wait_queue_head_t *q = folio_waitqueue(folio); unsigned long flags; spin_lock_irqsave(&q->lock, flags); __add_wait_queue_entry_tail(q, waiter); - SetPageWaiters(page); + folio_set_waiters(folio); spin_unlock_irqrestore(&q->lock, flags); } -EXPORT_SYMBOL_GPL(add_page_wait_queue); +EXPORT_SYMBOL_GPL(folio_add_wait_queue); #ifndef clear_bit_unlock_is_negative_byte @@ -1490,124 +1486,116 @@ static inline bool clear_bit_unlock_is_negative_byte(long nr, volatile void *mem #endif /** - * unlock_page - unlock a locked page - * @page: the page + * folio_unlock - Unlock a locked folio. + * @folio: The folio. * - * Unlocks the page and wakes up sleepers in wait_on_page_locked(). - * Also wakes sleepers in wait_on_page_writeback() because the wakeup - * mechanism between PageLocked pages and PageWriteback pages is shared. - * But that's OK - sleepers in wait_on_page_writeback() just go back to sleep. + * Unlocks the folio and wakes up any thread sleeping on the page lock. * - * Note that this depends on PG_waiters being the sign bit in the byte - * that contains PG_locked - thus the BUILD_BUG_ON(). That allows us to - * clear the PG_locked bit and test PG_waiters at the same time fairly - * portably (architectures that do LL/SC can test any bit, while x86 can - * test the sign bit). + * Context: May be called from interrupt or process context. May not be + * called from NMI context. */ -void unlock_page(struct page *page) +void folio_unlock(struct folio *folio) { + /* Bit 7 allows x86 to check the byte's sign bit */ BUILD_BUG_ON(PG_waiters != 7); - page = compound_head(page); - VM_BUG_ON_PAGE(!PageLocked(page), page); - if (clear_bit_unlock_is_negative_byte(PG_locked, &page->flags)) - wake_up_page_bit(page, PG_locked); + BUILD_BUG_ON(PG_locked > 7); + VM_BUG_ON_FOLIO(!folio_test_locked(folio), folio); + if (clear_bit_unlock_is_negative_byte(PG_locked, folio_flags(folio, 0))) + folio_wake_bit(folio, PG_locked); } -EXPORT_SYMBOL(unlock_page); +EXPORT_SYMBOL(folio_unlock); /** - * end_page_private_2 - Clear PG_private_2 and release any waiters - * @page: The page + * folio_end_private_2 - Clear PG_private_2 and wake any waiters. + * @folio: The folio. * - * Clear the PG_private_2 bit on a page and wake up any sleepers waiting for - * this. The page ref held for PG_private_2 being set is released. + * Clear the PG_private_2 bit on a folio and wake up any sleepers waiting for + * it. The folio reference held for PG_private_2 being set is released. * - * This is, for example, used when a netfs page is being written to a local - * disk cache, thereby allowing writes to the cache for the same page to be + * This is, for example, used when a netfs folio is being written to a local + * disk cache, thereby allowing writes to the cache for the same folio to be * serialised. */ -void end_page_private_2(struct page *page) +void folio_end_private_2(struct folio *folio) { - page = compound_head(page); - VM_BUG_ON_PAGE(!PagePrivate2(page), page); - clear_bit_unlock(PG_private_2, &page->flags); - wake_up_page_bit(page, PG_private_2); - put_page(page); + VM_BUG_ON_FOLIO(!folio_test_private_2(folio), folio); + clear_bit_unlock(PG_private_2, folio_flags(folio, 0)); + folio_wake_bit(folio, PG_private_2); + folio_put(folio); } -EXPORT_SYMBOL(end_page_private_2); +EXPORT_SYMBOL(folio_end_private_2); /** - * wait_on_page_private_2 - Wait for PG_private_2 to be cleared on a page - * @page: The page to wait on + * folio_wait_private_2 - Wait for PG_private_2 to be cleared on a folio. + * @folio: The folio to wait on. * - * Wait for PG_private_2 (aka PG_fscache) to be cleared on a page. + * Wait for PG_private_2 (aka PG_fscache) to be cleared on a folio. */ -void wait_on_page_private_2(struct page *page) +void folio_wait_private_2(struct folio *folio) { - page = compound_head(page); - while (PagePrivate2(page)) - wait_on_page_bit(page, PG_private_2); + while (folio_test_private_2(folio)) + folio_wait_bit(folio, PG_private_2); } -EXPORT_SYMBOL(wait_on_page_private_2); +EXPORT_SYMBOL(folio_wait_private_2); /** - * wait_on_page_private_2_killable - Wait for PG_private_2 to be cleared on a page - * @page: The page to wait on + * folio_wait_private_2_killable - Wait for PG_private_2 to be cleared on a folio. + * @folio: The folio to wait on. * - * Wait for PG_private_2 (aka PG_fscache) to be cleared on a page or until a + * Wait for PG_private_2 (aka PG_fscache) to be cleared on a folio or until a * fatal signal is received by the calling task. * * Return: * - 0 if successful. * - -EINTR if a fatal signal was encountered. */ -int wait_on_page_private_2_killable(struct page *page) +int folio_wait_private_2_killable(struct folio *folio) { int ret = 0; - page = compound_head(page); - while (PagePrivate2(page)) { - ret = wait_on_page_bit_killable(page, PG_private_2); + while (folio_test_private_2(folio)) { + ret = folio_wait_bit_killable(folio, PG_private_2); if (ret < 0) break; } return ret; } -EXPORT_SYMBOL(wait_on_page_private_2_killable); +EXPORT_SYMBOL(folio_wait_private_2_killable); /** - * end_page_writeback - end writeback against a page - * @page: the page + * folio_end_writeback - End writeback against a folio. + * @folio: The folio. */ -void end_page_writeback(struct page *page) +void folio_end_writeback(struct folio *folio) { /* - * TestClearPageReclaim could be used here but it is an atomic - * operation and overkill in this particular case. Failing to - * shuffle a page marked for immediate reclaim is too mild to - * justify taking an atomic operation penalty at the end of - * ever page writeback. + * folio_test_clear_reclaim() could be used here but it is an + * atomic operation and overkill in this particular case. Failing + * to shuffle a folio marked for immediate reclaim is too mild + * a gain to justify taking an atomic operation penalty at the + * end of every folio writeback. */ - if (PageReclaim(page)) { - ClearPageReclaim(page); - rotate_reclaimable_page(page); + if (folio_test_reclaim(folio)) { + folio_clear_reclaim(folio); + folio_rotate_reclaimable(folio); } /* - * Writeback does not hold a page reference of its own, relying + * Writeback does not hold a folio reference of its own, relying * on truncation to wait for the clearing of PG_writeback. - * But here we must make sure that the page is not freed and - * reused before the wake_up_page(). + * But here we must make sure that the folio is not freed and + * reused before the folio_wake(). */ - get_page(page); - if (!test_clear_page_writeback(page)) + folio_get(folio); + if (!__folio_end_writeback(folio)) BUG(); smp_mb__after_atomic(); - wake_up_page(page, PG_writeback); - put_page(page); + folio_wake(folio, PG_writeback); + folio_put(folio); } -EXPORT_SYMBOL(end_page_writeback); +EXPORT_SYMBOL(folio_end_writeback); /* * After completing I/O on a page, call this routine to update the page @@ -1638,39 +1626,35 @@ void page_endio(struct page *page, bool is_write, int err) EXPORT_SYMBOL_GPL(page_endio); /** - * __lock_page - get a lock on the page, assuming we need to sleep to get it - * @__page: the page to lock + * __folio_lock - Get a lock on the folio, assuming we need to sleep to get it. + * @folio: The folio to lock */ -void __lock_page(struct page *__page) +void __folio_lock(struct folio *folio) { - struct page *page = compound_head(__page); - wait_queue_head_t *q = page_waitqueue(page); - wait_on_page_bit_common(q, page, PG_locked, TASK_UNINTERRUPTIBLE, + folio_wait_bit_common(folio, PG_locked, TASK_UNINTERRUPTIBLE, EXCLUSIVE); } -EXPORT_SYMBOL(__lock_page); +EXPORT_SYMBOL(__folio_lock); -int __lock_page_killable(struct page *__page) +int __folio_lock_killable(struct folio *folio) { - struct page *page = compound_head(__page); - wait_queue_head_t *q = page_waitqueue(page); - return wait_on_page_bit_common(q, page, PG_locked, TASK_KILLABLE, + return folio_wait_bit_common(folio, PG_locked, TASK_KILLABLE, EXCLUSIVE); } -EXPORT_SYMBOL_GPL(__lock_page_killable); +EXPORT_SYMBOL_GPL(__folio_lock_killable); -int __lock_page_async(struct page *page, struct wait_page_queue *wait) +static int __folio_lock_async(struct folio *folio, struct wait_page_queue *wait) { - struct wait_queue_head *q = page_waitqueue(page); + struct wait_queue_head *q = folio_waitqueue(folio); int ret = 0; - wait->page = page; + wait->folio = folio; wait->bit_nr = PG_locked; spin_lock_irq(&q->lock); __add_wait_queue_entry_tail(q, &wait->wait); - SetPageWaiters(page); - ret = !trylock_page(page); + folio_set_waiters(folio); + ret = !folio_trylock(folio); /* * If we were successful now, we know we're still on the * waitqueue as we're still under the lock. This means it's @@ -1687,16 +1671,16 @@ int __lock_page_async(struct page *page, struct wait_page_queue *wait) /* * Return values: - * 1 - page is locked; mmap_lock is still held. - * 0 - page is not locked. + * true - folio is locked; mmap_lock is still held. + * false - folio is not locked. * mmap_lock has been released (mmap_read_unlock(), unless flags had both * FAULT_FLAG_ALLOW_RETRY and FAULT_FLAG_RETRY_NOWAIT set, in * which case mmap_lock is still held. * - * If neither ALLOW_RETRY nor KILLABLE are set, will always return 1 - * with the page locked and the mmap_lock unperturbed. + * If neither ALLOW_RETRY nor KILLABLE are set, will always return true + * with the folio locked and the mmap_lock unperturbed. */ -int __lock_page_or_retry(struct page *page, struct mm_struct *mm, +bool __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm, unsigned int flags) { if (fault_flag_allow_retry_first(flags)) { @@ -1705,28 +1689,28 @@ int __lock_page_or_retry(struct page *page, struct mm_struct *mm, * even though return 0. */ if (flags & FAULT_FLAG_RETRY_NOWAIT) - return 0; + return false; mmap_read_unlock(mm); if (flags & FAULT_FLAG_KILLABLE) - wait_on_page_locked_killable(page); + folio_wait_locked_killable(folio); else - wait_on_page_locked(page); - return 0; + folio_wait_locked(folio); + return false; } if (flags & FAULT_FLAG_KILLABLE) { - int ret; + bool ret; - ret = __lock_page_killable(page); + ret = __folio_lock_killable(folio); if (ret) { mmap_read_unlock(mm); - return 0; + return false; } } else { - __lock_page(page); + __folio_lock(folio); } - return 1; + return true; } /** @@ -1802,143 +1786,155 @@ pgoff_t page_cache_prev_miss(struct address_space *mapping, EXPORT_SYMBOL(page_cache_prev_miss); /* + * Lockless page cache protocol: + * On the lookup side: + * 1. Load the folio from i_pages + * 2. Increment the refcount if it's not zero + * 3. If the folio is not found by xas_reload(), put the refcount and retry + * + * On the removal side: + * A. Freeze the page (by zeroing the refcount if nobody else has a reference) + * B. Remove the page from i_pages + * C. Return the page to the page allocator + * + * This means that any page may have its reference count temporarily + * increased by a speculative page cache (or fast GUP) lookup as it can + * be allocated by another user before the RCU grace period expires. + * Because the refcount temporarily acquired here may end up being the + * last refcount on the page, any page allocation must be freeable by + * folio_put(). + */ + +/* * mapping_get_entry - Get a page cache entry. * @mapping: the address_space to search * @index: The page cache index. * - * Looks up the page cache slot at @mapping & @index. If there is a - * page cache page, the head page is returned with an increased refcount. + * Looks up the page cache entry at @mapping & @index. If it is a folio, + * it is returned with an increased refcount. If it is a shadow entry + * of a previously evicted folio, or a swap entry from shmem/tmpfs, + * it is returned without further action. * - * If the slot holds a shadow entry of a previously evicted page, or a - * swap entry from shmem/tmpfs, it is returned. - * - * Return: The head page or shadow entry, %NULL if nothing is found. + * Return: The folio, swap or shadow entry, %NULL if nothing is found. */ -static struct page *mapping_get_entry(struct address_space *mapping, - pgoff_t index) +static void *mapping_get_entry(struct address_space *mapping, pgoff_t index) { XA_STATE(xas, &mapping->i_pages, index); - struct page *page; + struct folio *folio; rcu_read_lock(); repeat: xas_reset(&xas); - page = xas_load(&xas); - if (xas_retry(&xas, page)) + folio = xas_load(&xas); + if (xas_retry(&xas, folio)) goto repeat; /* * A shadow entry of a recently evicted page, or a swap entry from * shmem/tmpfs. Return it without attempting to raise page count. */ - if (!page || xa_is_value(page)) + if (!folio || xa_is_value(folio)) goto out; - if (!page_cache_get_speculative(page)) + if (!folio_try_get_rcu(folio)) goto repeat; - /* - * Has the page moved or been split? - * This is part of the lockless pagecache protocol. See - * include/linux/pagemap.h for details. - */ - if (unlikely(page != xas_reload(&xas))) { - put_page(page); + if (unlikely(folio != xas_reload(&xas))) { + folio_put(folio); goto repeat; } out: rcu_read_unlock(); - return page; + return folio; } /** - * pagecache_get_page - Find and get a reference to a page. + * __filemap_get_folio - Find and get a reference to a folio. * @mapping: The address_space to search. * @index: The page index. - * @fgp_flags: %FGP flags modify how the page is returned. - * @gfp_mask: Memory allocation flags to use if %FGP_CREAT is specified. + * @fgp_flags: %FGP flags modify how the folio is returned. + * @gfp: Memory allocation flags to use if %FGP_CREAT is specified. * * Looks up the page cache entry at @mapping & @index. * * @fgp_flags can be zero or more of these flags: * - * * %FGP_ACCESSED - The page will be marked accessed. - * * %FGP_LOCK - The page is returned locked. - * * %FGP_HEAD - If the page is present and a THP, return the head page - * rather than the exact page specified by the index. + * * %FGP_ACCESSED - The folio will be marked accessed. + * * %FGP_LOCK - The folio is returned locked. * * %FGP_ENTRY - If there is a shadow / swap / DAX entry, return it - * instead of allocating a new page to replace it. + * instead of allocating a new folio to replace it. * * %FGP_CREAT - If no page is present then a new page is allocated using - * @gfp_mask and added to the page cache and the VM's LRU list. + * @gfp and added to the page cache and the VM's LRU list. * The page is returned locked and with an increased refcount. * * %FGP_FOR_MMAP - The caller wants to do its own locking dance if the * page is already in cache. If the page was allocated, unlock it before * returning so the caller can do the same dance. - * * %FGP_WRITE - The page will be written - * * %FGP_NOFS - __GFP_FS will get cleared in gfp mask - * * %FGP_NOWAIT - Don't get blocked by page lock + * * %FGP_WRITE - The page will be written to by the caller. + * * %FGP_NOFS - __GFP_FS will get cleared in gfp. + * * %FGP_NOWAIT - Don't get blocked by page lock. + * * %FGP_STABLE - Wait for the folio to be stable (finished writeback) * * If %FGP_LOCK or %FGP_CREAT are specified then the function may sleep even * if the %GFP flags specified for %FGP_CREAT are atomic. * * If there is a page cache page, it is returned with an increased refcount. * - * Return: The found page or %NULL otherwise. + * Return: The found folio or %NULL otherwise. */ -struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index, - int fgp_flags, gfp_t gfp_mask) +struct folio *__filemap_get_folio(struct address_space *mapping, pgoff_t index, + int fgp_flags, gfp_t gfp) { - struct page *page; + struct folio *folio; repeat: - page = mapping_get_entry(mapping, index); - if (xa_is_value(page)) { + folio = mapping_get_entry(mapping, index); + if (xa_is_value(folio)) { if (fgp_flags & FGP_ENTRY) - return page; - page = NULL; + return folio; + folio = NULL; } - if (!page) + if (!folio) goto no_page; if (fgp_flags & FGP_LOCK) { if (fgp_flags & FGP_NOWAIT) { - if (!trylock_page(page)) { - put_page(page); + if (!folio_trylock(folio)) { + folio_put(folio); return NULL; } } else { - lock_page(page); + folio_lock(folio); } /* Has the page been truncated? */ - if (unlikely(page->mapping != mapping)) { - unlock_page(page); - put_page(page); + if (unlikely(folio->mapping != mapping)) { + folio_unlock(folio); + folio_put(folio); goto repeat; } - VM_BUG_ON_PAGE(!thp_contains(page, index), page); + VM_BUG_ON_FOLIO(!folio_contains(folio, index), folio); } if (fgp_flags & FGP_ACCESSED) - mark_page_accessed(page); + folio_mark_accessed(folio); else if (fgp_flags & FGP_WRITE) { /* Clear idle flag for buffer write */ - if (page_is_idle(page)) - clear_page_idle(page); + if (folio_test_idle(folio)) + folio_clear_idle(folio); } - if (!(fgp_flags & FGP_HEAD)) - page = find_subpage(page, index); + if (fgp_flags & FGP_STABLE) + folio_wait_stable(folio); no_page: - if (!page && (fgp_flags & FGP_CREAT)) { + if (!folio && (fgp_flags & FGP_CREAT)) { int err; if ((fgp_flags & FGP_WRITE) && mapping_can_writeback(mapping)) - gfp_mask |= __GFP_WRITE; + gfp |= __GFP_WRITE; if (fgp_flags & FGP_NOFS) - gfp_mask &= ~__GFP_FS; + gfp &= ~__GFP_FS; - page = __page_cache_alloc(gfp_mask); - if (!page) + folio = filemap_alloc_folio(gfp, 0); + if (!folio) return NULL; if (WARN_ON_ONCE(!(fgp_flags & (FGP_LOCK | FGP_FOR_MMAP)))) @@ -1946,27 +1942,27 @@ no_page: /* Init accessed so avoid atomic mark_page_accessed later */ if (fgp_flags & FGP_ACCESSED) - __SetPageReferenced(page); + __folio_set_referenced(folio); - err = add_to_page_cache_lru(page, mapping, index, gfp_mask); + err = filemap_add_folio(mapping, folio, index, gfp); if (unlikely(err)) { - put_page(page); - page = NULL; + folio_put(folio); + folio = NULL; if (err == -EEXIST) goto repeat; } /* - * add_to_page_cache_lru locks the page, and for mmap we expect - * an unlocked page. + * filemap_add_folio locks the page, and for mmap + * we expect an unlocked page. */ - if (page && (fgp_flags & FGP_FOR_MMAP)) - unlock_page(page); + if (folio && (fgp_flags & FGP_FOR_MMAP)) + folio_unlock(folio); } - return page; + return folio; } -EXPORT_SYMBOL(pagecache_get_page); +EXPORT_SYMBOL(__filemap_get_folio); static inline struct page *find_get_entry(struct xa_state *xas, pgoff_t max, xa_mark_t mark) @@ -2421,6 +2417,7 @@ static int filemap_update_page(struct kiocb *iocb, struct address_space *mapping, struct iov_iter *iter, struct page *page) { + struct folio *folio = page_folio(page); int error; if (iocb->ki_flags & IOCB_NOWAIT) { @@ -2430,40 +2427,40 @@ static int filemap_update_page(struct kiocb *iocb, filemap_invalidate_lock_shared(mapping); } - if (!trylock_page(page)) { + if (!folio_trylock(folio)) { error = -EAGAIN; if (iocb->ki_flags & (IOCB_NOWAIT | IOCB_NOIO)) goto unlock_mapping; if (!(iocb->ki_flags & IOCB_WAITQ)) { filemap_invalidate_unlock_shared(mapping); - put_and_wait_on_page_locked(page, TASK_KILLABLE); + put_and_wait_on_page_locked(&folio->page, TASK_KILLABLE); return AOP_TRUNCATED_PAGE; } - error = __lock_page_async(page, iocb->ki_waitq); + error = __folio_lock_async(folio, iocb->ki_waitq); if (error) goto unlock_mapping; } error = AOP_TRUNCATED_PAGE; - if (!page->mapping) + if (!folio->mapping) goto unlock; error = 0; - if (filemap_range_uptodate(mapping, iocb->ki_pos, iter, page)) + if (filemap_range_uptodate(mapping, iocb->ki_pos, iter, &folio->page)) goto unlock; error = -EAGAIN; if (iocb->ki_flags & (IOCB_NOIO | IOCB_NOWAIT | IOCB_WAITQ)) goto unlock; - error = filemap_read_page(iocb->ki_filp, mapping, page); + error = filemap_read_page(iocb->ki_filp, mapping, &folio->page); goto unlock_mapping; unlock: - unlock_page(page); + folio_unlock(folio); unlock_mapping: filemap_invalidate_unlock_shared(mapping); if (error == AOP_TRUNCATED_PAGE) - put_page(page); + folio_put(folio); return error; } @@ -2900,7 +2897,9 @@ unlock: static int lock_page_maybe_drop_mmap(struct vm_fault *vmf, struct page *page, struct file **fpin) { - if (trylock_page(page)) + struct folio *folio = page_folio(page); + + if (folio_trylock(folio)) return 1; /* @@ -2913,7 +2912,7 @@ static int lock_page_maybe_drop_mmap(struct vm_fault *vmf, struct page *page, *fpin = maybe_unlock_mmap_for_io(vmf, *fpin); if (vmf->flags & FAULT_FLAG_KILLABLE) { - if (__lock_page_killable(page)) { + if (__folio_lock_killable(folio)) { /* * We didn't have the right flags to drop the mmap_lock, * but all fault_handlers only check for fatal signals @@ -2925,11 +2924,11 @@ static int lock_page_maybe_drop_mmap(struct vm_fault *vmf, struct page *page, return 0; } } else - __lock_page(page); + __folio_lock(folio); + return 1; } - /* * Synchronous readahead happens when we don't even find a page in the page * cache at all. We don't want to perform IO under the mmap sem, so if we have @@ -3708,28 +3707,6 @@ out: } EXPORT_SYMBOL(generic_file_direct_write); -/* - * Find or create a page at the given pagecache position. Return the locked - * page. This function is specifically for buffered writes. - */ -struct page *grab_cache_page_write_begin(struct address_space *mapping, - pgoff_t index, unsigned flags) -{ - struct page *page; - int fgp_flags = FGP_LOCK|FGP_WRITE|FGP_CREAT; - - if (flags & AOP_FLAG_NOFS) - fgp_flags |= FGP_NOFS; - - page = pagecache_get_page(mapping, index, fgp_flags, - mapping_gfp_mask(mapping)); - if (page) - wait_for_stable_page(page); - - return page; -} -EXPORT_SYMBOL(grab_cache_page_write_begin); - ssize_t generic_perform_write(struct file *file, struct iov_iter *i, loff_t pos) { |