| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * linux/mm/swap.c |
| * |
| * Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds |
| */ |
| |
| /* |
| * This file contains the default values for the operation of the |
| * Linux VM subsystem. Fine-tuning documentation can be found in |
| * Documentation/admin-guide/sysctl/vm.rst. |
| * Started 18.12.91 |
| * Swap aging added 23.2.95, Stephen Tweedie. |
| * Buffermem limits added 12.3.98, Rik van Riel. |
| */ |
| |
| #include <linux/mm.h> |
| #include <linux/sched.h> |
| #include <linux/kernel_stat.h> |
| #include <linux/swap.h> |
| #include <linux/mman.h> |
| #include <linux/pagemap.h> |
| #include <linux/pagevec.h> |
| #include <linux/init.h> |
| #include <linux/export.h> |
| #include <linux/mm_inline.h> |
| #include <linux/percpu_counter.h> |
| #include <linux/memremap.h> |
| #include <linux/percpu.h> |
| #include <linux/cpu.h> |
| #include <linux/notifier.h> |
| #include <linux/backing-dev.h> |
| #include <linux/memcontrol.h> |
| #include <linux/gfp.h> |
| #include <linux/uio.h> |
| #include <linux/hugetlb.h> |
| #include <linux/page_idle.h> |
| #include <linux/local_lock.h> |
| |
| #include "internal.h" |
| |
| #define CREATE_TRACE_POINTS |
| #include <trace/events/pagemap.h> |
| |
| /* How many pages do we try to swap or page in/out together? */ |
| int page_cluster; |
| |
| /* Protecting only lru_rotate.pvec which requires disabling interrupts */ |
| struct lru_rotate { |
| local_lock_t lock; |
| struct pagevec pvec; |
| }; |
| static DEFINE_PER_CPU(struct lru_rotate, lru_rotate) = { |
| .lock = INIT_LOCAL_LOCK(lock), |
| }; |
| |
| /* |
| * The following struct pagevec are grouped together because they are protected |
| * by disabling preemption (and interrupts remain enabled). |
| */ |
| struct lru_pvecs { |
| local_lock_t lock; |
| struct pagevec lru_add; |
| struct pagevec lru_deactivate_file; |
| struct pagevec lru_deactivate; |
| struct pagevec lru_lazyfree; |
| #ifdef CONFIG_SMP |
| struct pagevec activate_page; |
| #endif |
| }; |
| static DEFINE_PER_CPU(struct lru_pvecs, lru_pvecs) = { |
| .lock = INIT_LOCAL_LOCK(lock), |
| }; |
| |
| /* |
| * This path almost never happens for VM activity - pages are normally |
| * freed via pagevecs. But it gets used by networking. |
| */ |
| static void __page_cache_release(struct page *page) |
| { |
| if (PageLRU(page)) { |
| pg_data_t *pgdat = page_pgdat(page); |
| struct lruvec *lruvec; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&pgdat->lru_lock, flags); |
| lruvec = mem_cgroup_page_lruvec(page, pgdat); |
| VM_BUG_ON_PAGE(!PageLRU(page), page); |
| __ClearPageLRU(page); |
| del_page_from_lru_list(page, lruvec, page_off_lru(page)); |
| spin_unlock_irqrestore(&pgdat->lru_lock, flags); |
| } |
| __ClearPageWaiters(page); |
| } |
| |
| static void __put_single_page(struct page *page) |
| { |
| __page_cache_release(page); |
| mem_cgroup_uncharge(page); |
| free_unref_page(page); |
| } |
| |
| static void __put_compound_page(struct page *page) |
| { |
| compound_page_dtor *dtor; |
| |
| /* |
| * __page_cache_release() is supposed to be called for thp, not for |
| * hugetlb. This is because hugetlb page does never have PageLRU set |
| * (it's never listed to any LRU lists) and no memcg routines should |
| * be called for hugetlb (it has a separate hugetlb_cgroup.) |
| */ |
| if (!PageHuge(page)) |
| __page_cache_release(page); |
| dtor = get_compound_page_dtor(page); |
| (*dtor)(page); |
| } |
| |
| void __put_page(struct page *page) |
| { |
| if (is_zone_device_page(page)) { |
| put_dev_pagemap(page->pgmap); |
| |
| /* |
| * The page belongs to the device that created pgmap. Do |
| * not return it to page allocator. |
| */ |
| return; |
| } |
| |
| if (unlikely(PageCompound(page))) |
| __put_compound_page(page); |
| else |
| __put_single_page(page); |
| } |
| EXPORT_SYMBOL(__put_page); |
| |
| /** |
| * put_pages_list() - release a list of pages |
| * @pages: list of pages threaded on page->lru |
| * |
| * Release a list of pages which are strung together on page.lru. Currently |
| * used by read_cache_pages() and related error recovery code. |
| */ |
| void put_pages_list(struct list_head *pages) |
| { |
| while (!list_empty(pages)) { |
| struct page *victim; |
| |
| victim = lru_to_page(pages); |
| list_del(&victim->lru); |
| put_page(victim); |
| } |
| } |
| EXPORT_SYMBOL(put_pages_list); |
| |
| /* |
| * get_kernel_pages() - pin kernel pages in memory |
| * @kiov: An array of struct kvec structures |
| * @nr_segs: number of segments to pin |
| * @write: pinning for read/write, currently ignored |
| * @pages: array that receives pointers to the pages pinned. |
| * Should be at least nr_segs long. |
| * |
| * Returns number of pages pinned. This may be fewer than the number |
| * requested. If nr_pages is 0 or negative, returns 0. If no pages |
| * were pinned, returns -errno. Each page returned must be released |
| * with a put_page() call when it is finished with. |
| */ |
| int get_kernel_pages(const struct kvec *kiov, int nr_segs, int write, |
| struct page **pages) |
| { |
| int seg; |
| |
| for (seg = 0; seg < nr_segs; seg++) { |
| if (WARN_ON(kiov[seg].iov_len != PAGE_SIZE)) |
| return seg; |
| |
| pages[seg] = kmap_to_page(kiov[seg].iov_base); |
| get_page(pages[seg]); |
| } |
| |
| return seg; |
| } |
| EXPORT_SYMBOL_GPL(get_kernel_pages); |
| |
| /* |
| * get_kernel_page() - pin a kernel page in memory |
| * @start: starting kernel address |
| * @write: pinning for read/write, currently ignored |
| * @pages: array that receives pointer to the page pinned. |
| * Must be at least nr_segs long. |
| * |
| * Returns 1 if page is pinned. If the page was not pinned, returns |
| * -errno. The page returned must be released with a put_page() call |
| * when it is finished with. |
| */ |
| int get_kernel_page(unsigned long start, int write, struct page **pages) |
| { |
| const struct kvec kiov = { |
| .iov_base = (void *)start, |
| .iov_len = PAGE_SIZE |
| }; |
| |
| return get_kernel_pages(&kiov, 1, write, pages); |
| } |
| EXPORT_SYMBOL_GPL(get_kernel_page); |
| |
| static void pagevec_lru_move_fn(struct pagevec *pvec, |
| void (*move_fn)(struct page *page, struct lruvec *lruvec, void *arg), |
| void *arg) |
| { |
| int i; |
| struct pglist_data *pgdat = NULL; |
| struct lruvec *lruvec; |
| unsigned long flags = 0; |
| |
| for (i = 0; i < pagevec_count(pvec); i++) { |
| struct page *page = pvec->pages[i]; |
| struct pglist_data *pagepgdat = page_pgdat(page); |
| |
| if (pagepgdat != pgdat) { |
| if (pgdat) |
| spin_unlock_irqrestore(&pgdat->lru_lock, flags); |
| pgdat = pagepgdat; |
| spin_lock_irqsave(&pgdat->lru_lock, flags); |
| } |
| |
| lruvec = mem_cgroup_page_lruvec(page, pgdat); |
| (*move_fn)(page, lruvec, arg); |
| } |
| if (pgdat) |
| spin_unlock_irqrestore(&pgdat->lru_lock, flags); |
| release_pages(pvec->pages, pvec->nr); |
| pagevec_reinit(pvec); |
| } |
| |
| static void pagevec_move_tail_fn(struct page *page, struct lruvec *lruvec, |
| void *arg) |
| { |
| int *pgmoved = arg; |
| |
| if (PageLRU(page) && !PageUnevictable(page)) { |
| del_page_from_lru_list(page, lruvec, page_lru(page)); |
| ClearPageActive(page); |
| add_page_to_lru_list_tail(page, lruvec, page_lru(page)); |
| (*pgmoved)++; |
| } |
| } |
| |
| /* |
| * pagevec_move_tail() must be called with IRQ disabled. |
| * Otherwise this may cause nasty races. |
| */ |
| static void pagevec_move_tail(struct pagevec *pvec) |
| { |
| int pgmoved = 0; |
| |
| pagevec_lru_move_fn(pvec, pagevec_move_tail_fn, &pgmoved); |
| __count_vm_events(PGROTATED, pgmoved); |
| } |
| |
| /* |
| * Writeback is about to end against a page which has been marked for immediate |
| * reclaim. If it still appears to be reclaimable, move it to the tail of the |
| * inactive list. |
| */ |
| void rotate_reclaimable_page(struct page *page) |
| { |
| if (!PageLocked(page) && !PageDirty(page) && |
| !PageUnevictable(page) && PageLRU(page)) { |
| struct pagevec *pvec; |
| unsigned long flags; |
| |
| get_page(page); |
| local_lock_irqsave(&lru_rotate.lock, flags); |
| pvec = this_cpu_ptr(&lru_rotate.pvec); |
| if (!pagevec_add(pvec, page) || PageCompound(page)) |
| pagevec_move_tail(pvec); |
| local_unlock_irqrestore(&lru_rotate.lock, flags); |
| } |
| } |
| |
| static void update_page_reclaim_stat(struct lruvec *lruvec, |
| int file, int rotated) |
| { |
| struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat; |
| |
| reclaim_stat->recent_scanned[file]++; |
| if (rotated) |
| reclaim_stat->recent_rotated[file]++; |
| } |
| |
| static void __activate_page(struct page *page, struct lruvec *lruvec, |
| void *arg) |
| { |
| if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { |
| int file = page_is_file_lru(page); |
| int lru = page_lru_base_type(page); |
| |
| del_page_from_lru_list(page, lruvec, lru); |
| SetPageActive(page); |
| lru += LRU_ACTIVE; |
| add_page_to_lru_list(page, lruvec, lru); |
| trace_mm_lru_activate(page); |
| |
| __count_vm_event(PGACTIVATE); |
| update_page_reclaim_stat(lruvec, file, 1); |
| } |
| } |
| |
| #ifdef CONFIG_SMP |
| static void activate_page_drain(int cpu) |
| { |
| struct pagevec *pvec = &per_cpu(lru_pvecs.activate_page, cpu); |
| |
| if (pagevec_count(pvec)) |
| pagevec_lru_move_fn(pvec, __activate_page, NULL); |
| } |
| |
| static bool need_activate_page_drain(int cpu) |
| { |
| return pagevec_count(&per_cpu(lru_pvecs.activate_page, cpu)) != 0; |
| } |
| |
| void activate_page(struct page *page) |
| { |
| page = compound_head(page); |
| if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) { |
| struct pagevec *pvec; |
| |
| local_lock(&lru_pvecs.lock); |
| pvec = this_cpu_ptr(&lru_pvecs.activate_page); |
| get_page(page); |
| if (!pagevec_add(pvec, page) || PageCompound(page)) |
| pagevec_lru_move_fn(pvec, __activate_page, NULL); |
| local_unlock(&lru_pvecs.lock); |
| } |
| } |
| |
| #else |
| static inline void activate_page_drain(int cpu) |
| { |
| } |
| |
| void activate_page(struct page *page) |
| { |
| pg_data_t *pgdat = page_pgdat(page); |
| |
| page = compound_head(page); |
| spin_lock_irq(&pgdat->lru_lock); |
| __activate_page(page, mem_cgroup_page_lruvec(page, pgdat), NULL); |
| spin_unlock_irq(&pgdat->lru_lock); |
| } |
| #endif |
| |
| static void __lru_cache_activate_page(struct page *page) |
| { |
| struct pagevec *pvec; |
| int i; |
| |
| local_lock(&lru_pvecs.lock); |
| pvec = this_cpu_ptr(&lru_pvecs.lru_add); |
| |
| /* |
| * Search backwards on the optimistic assumption that the page being |
| * activated has just been added to this pagevec. Note that only |
| * the local pagevec is examined as a !PageLRU page could be in the |
| * process of being released, reclaimed, migrated or on a remote |
| * pagevec that is currently being drained. Furthermore, marking |
| * a remote pagevec's page PageActive potentially hits a race where |
| * a page is marked PageActive just after it is added to the inactive |
| * list causing accounting errors and BUG_ON checks to trigger. |
| */ |
| for (i = pagevec_count(pvec) - 1; i >= 0; i--) { |
| struct page *pagevec_page = pvec->pages[i]; |
| |
| if (pagevec_page == page) { |
| SetPageActive(page); |
| break; |
| } |
| } |
| |
| local_unlock(&lru_pvecs.lock); |
| } |
| |
| /* |
| * Mark a page as having seen activity. |
| * |
| * inactive,unreferenced -> inactive,referenced |
| * inactive,referenced -> active,unreferenced |
| * active,unreferenced -> active,referenced |
| * |
| * When a newly allocated page is not yet visible, so safe for non-atomic ops, |
| * __SetPageReferenced(page) may be substituted for mark_page_accessed(page). |
| */ |
| void mark_page_accessed(struct page *page) |
| { |
| page = compound_head(page); |
| |
| if (!PageReferenced(page)) { |
| SetPageReferenced(page); |
| } else if (PageUnevictable(page)) { |
| /* |
| * Unevictable pages are on the "LRU_UNEVICTABLE" list. But, |
| * this list is never rotated or maintained, so marking an |
| * evictable page accessed has no effect. |
| */ |
| } else if (!PageActive(page)) { |
| /* |
| * If the page is on the LRU, queue it for activation via |
| * lru_pvecs.activate_page. Otherwise, assume the page is on a |
| * pagevec, mark it active and it'll be moved to the active |
| * LRU on the next drain. |
| */ |
| if (PageLRU(page)) |
| activate_page(page); |
| else |
| __lru_cache_activate_page(page); |
| ClearPageReferenced(page); |
| if (page_is_file_lru(page)) |
| workingset_activation(page); |
| } |
| if (page_is_idle(page)) |
| clear_page_idle(page); |
| } |
| EXPORT_SYMBOL(mark_page_accessed); |
| |
| static void __lru_cache_add(struct page *page) |
| { |
| struct pagevec *pvec; |
| |
| local_lock(&lru_pvecs.lock); |
| pvec = this_cpu_ptr(&lru_pvecs.lru_add); |
| get_page(page); |
| if (!pagevec_add(pvec, page) || PageCompound(page)) |
| __pagevec_lru_add(pvec); |
| local_unlock(&lru_pvecs.lock); |
| } |
| |
| /** |
| * lru_cache_add_anon - add a page to the page lists |
| * @page: the page to add |
| */ |
| void lru_cache_add_anon(struct page *page) |
| { |
| if (PageActive(page)) |
| ClearPageActive(page); |
| __lru_cache_add(page); |
| } |
| |
| void lru_cache_add_file(struct page *page) |
| { |
| if (PageActive(page)) |
| ClearPageActive(page); |
| __lru_cache_add(page); |
| } |
| EXPORT_SYMBOL(lru_cache_add_file); |
| |
| /** |
| * lru_cache_add - add a page to a page list |
| * @page: the page to be added to the LRU. |
| * |
| * Queue the page for addition to the LRU via pagevec. The decision on whether |
| * to add the page to the [in]active [file|anon] list is deferred until the |
| * pagevec is drained. This gives a chance for the caller of lru_cache_add() |
| * have the page added to the active list using mark_page_accessed(). |
| */ |
| void lru_cache_add(struct page *page) |
| { |
| VM_BUG_ON_PAGE(PageActive(page) && PageUnevictable(page), page); |
| VM_BUG_ON_PAGE(PageLRU(page), page); |
| __lru_cache_add(page); |
| } |
| |
| /** |
| * lru_cache_add_active_or_unevictable |
| * @page: the page to be added to LRU |
| * @vma: vma in which page is mapped for determining reclaimability |
| * |
| * Place @page on the active or unevictable LRU list, depending on its |
| * evictability. Note that if the page is not evictable, it goes |
| * directly back onto it's zone's unevictable list, it does NOT use a |
| * per cpu pagevec. |
| */ |
| void lru_cache_add_active_or_unevictable(struct page *page, |
| struct vm_area_struct *vma) |
| { |
| VM_BUG_ON_PAGE(PageLRU(page), page); |
| |
| if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED)) |
| SetPageActive(page); |
| else if (!TestSetPageMlocked(page)) { |
| /* |
| * We use the irq-unsafe __mod_zone_page_stat because this |
| * counter is not modified from interrupt context, and the pte |
| * lock is held(spinlock), which implies preemption disabled. |
| */ |
| __mod_zone_page_state(page_zone(page), NR_MLOCK, |
| hpage_nr_pages(page)); |
| count_vm_event(UNEVICTABLE_PGMLOCKED); |
| } |
| lru_cache_add(page); |
| } |
| |
| /* |
| * If the page can not be invalidated, it is moved to the |
| * inactive list to speed up its reclaim. It is moved to the |
| * head of the list, rather than the tail, to give the flusher |
| * threads some time to write it out, as this is much more |
| * effective than the single-page writeout from reclaim. |
| * |
| * If the page isn't page_mapped and dirty/writeback, the page |
| * could reclaim asap using PG_reclaim. |
| * |
| * 1. active, mapped page -> none |
| * 2. active, dirty/writeback page -> inactive, head, PG_reclaim |
| * 3. inactive, mapped page -> none |
| * 4. inactive, dirty/writeback page -> inactive, head, PG_reclaim |
| * 5. inactive, clean -> inactive, tail |
| * 6. Others -> none |
| * |
| * In 4, why it moves inactive's head, the VM expects the page would |
| * be write it out by flusher threads as this is much more effective |
| * than the single-page writeout from reclaim. |
| */ |
| static void lru_deactivate_file_fn(struct page *page, struct lruvec *lruvec, |
| void *arg) |
| { |
| int lru, file; |
| bool active; |
| |
| if (!PageLRU(page)) |
| return; |
| |
| if (PageUnevictable(page)) |
| return; |
| |
| /* Some processes are using the page */ |
| if (page_mapped(page)) |
| return; |
| |
| active = PageActive(page); |
| file = page_is_file_lru(page); |
| lru = page_lru_base_type(page); |
| |
| del_page_from_lru_list(page, lruvec, lru + active); |
| ClearPageActive(page); |
| ClearPageReferenced(page); |
| |
| if (PageWriteback(page) || PageDirty(page)) { |
| /* |
| * PG_reclaim could be raced with end_page_writeback |
| * It can make readahead confusing. But race window |
| * is _really_ small and it's non-critical problem. |
| */ |
| add_page_to_lru_list(page, lruvec, lru); |
| SetPageReclaim(page); |
| } else { |
| /* |
| * The page's writeback ends up during pagevec |
| * We moves tha page into tail of inactive. |
| */ |
| add_page_to_lru_list_tail(page, lruvec, lru); |
| __count_vm_event(PGROTATED); |
| } |
| |
| if (active) |
| __count_vm_event(PGDEACTIVATE); |
| update_page_reclaim_stat(lruvec, file, 0); |
| } |
| |
| static void lru_deactivate_fn(struct page *page, struct lruvec *lruvec, |
| void *arg) |
| { |
| if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) { |
| int file = page_is_file_lru(page); |
| int lru = page_lru_base_type(page); |
| |
| del_page_from_lru_list(page, lruvec, lru + LRU_ACTIVE); |
| ClearPageActive(page); |
| ClearPageReferenced(page); |
| add_page_to_lru_list(page, lruvec, lru); |
| |
| __count_vm_events(PGDEACTIVATE, hpage_nr_pages(page)); |
| update_page_reclaim_stat(lruvec, file, 0); |
| } |
| } |
| |
| static void lru_lazyfree_fn(struct page *page, struct lruvec *lruvec, |
| void *arg) |
| { |
| if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) && |
| !PageSwapCache(page) && !PageUnevictable(page)) { |
| bool active = PageActive(page); |
| |
| del_page_from_lru_list(page, lruvec, |
| LRU_INACTIVE_ANON + active); |
| ClearPageActive(page); |
| ClearPageReferenced(page); |
| /* |
| * Lazyfree pages are clean anonymous pages. They have |
| * PG_swapbacked flag cleared, to distinguish them from normal |
| * anonymous pages |
| */ |
| ClearPageSwapBacked(page); |
| add_page_to_lru_list(page, lruvec, LRU_INACTIVE_FILE); |
| |
| __count_vm_events(PGLAZYFREE, hpage_nr_pages(page)); |
| count_memcg_page_event(page, PGLAZYFREE); |
| update_page_reclaim_stat(lruvec, 1, 0); |
| } |
| } |
| |
| /* |
| * Drain pages out of the cpu's pagevecs. |
| * Either "cpu" is the current CPU, and preemption has already been |
| * disabled; or "cpu" is being hot-unplugged, and is already dead. |
| */ |
| void lru_add_drain_cpu(int cpu) |
| { |
| struct pagevec *pvec = &per_cpu(lru_pvecs.lru_add, cpu); |
| |
| if (pagevec_count(pvec)) |
| __pagevec_lru_add(pvec); |
| |
| pvec = &per_cpu(lru_rotate.pvec, cpu); |
| if (pagevec_count(pvec)) { |
| unsigned long flags; |
| |
| /* No harm done if a racing interrupt already did this */ |
| local_lock_irqsave(&lru_rotate.lock, flags); |
| pagevec_move_tail(pvec); |
| local_unlock_irqrestore(&lru_rotate.lock, flags); |
| } |
| |
| pvec = &per_cpu(lru_pvecs.lru_deactivate_file, cpu); |
| if (pagevec_count(pvec)) |
| pagevec_lru_move_fn(pvec, lru_deactivate_file_fn, NULL); |
| |
| pvec = &per_cpu(lru_pvecs.lru_deactivate, cpu); |
| if (pagevec_count(pvec)) |
| pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL); |
| |
| pvec = &per_cpu(lru_pvecs.lru_lazyfree, cpu); |
| if (pagevec_count(pvec)) |
| pagevec_lru_move_fn(pvec, lru_lazyfree_fn, NULL); |
| |
| activate_page_drain(cpu); |
| } |
| |
| /** |
| * deactivate_file_page - forcefully deactivate a file page |
| * @page: page to deactivate |
| * |
| * This function hints the VM that @page is a good reclaim candidate, |
| * for example if its invalidation fails due to the page being dirty |
| * or under writeback. |
| */ |
| void deactivate_file_page(struct page *page) |
| { |
| /* |
| * In a workload with many unevictable page such as mprotect, |
| * unevictable page deactivation for accelerating reclaim is pointless. |
| */ |
| if (PageUnevictable(page)) |
| return; |
| |
| if (likely(get_page_unless_zero(page))) { |
| struct pagevec *pvec; |
| |
| local_lock(&lru_pvecs.lock); |
| pvec = this_cpu_ptr(&lru_pvecs.lru_deactivate_file); |
| |
| if (!pagevec_add(pvec, page) || PageCompound(page)) |
| pagevec_lru_move_fn(pvec, lru_deactivate_file_fn, NULL); |
| local_unlock(&lru_pvecs.lock); |
| } |
| } |
| |
| /* |
| * deactivate_page - deactivate a page |
| * @page: page to deactivate |
| * |
| * deactivate_page() moves @page to the inactive list if @page was on the active |
| * list and was not an unevictable page. This is done to accelerate the reclaim |
| * of @page. |
| */ |
| void deactivate_page(struct page *page) |
| { |
| if (PageLRU(page) && PageActive(page) && !PageUnevictable(page)) { |
| struct pagevec *pvec; |
| |
| local_lock(&lru_pvecs.lock); |
| pvec = this_cpu_ptr(&lru_pvecs.lru_deactivate); |
| get_page(page); |
| if (!pagevec_add(pvec, page) || PageCompound(page)) |
| pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL); |
| local_unlock(&lru_pvecs.lock); |
| } |
| } |
| |
| /** |
| * mark_page_lazyfree - make an anon page lazyfree |
| * @page: page to deactivate |
| * |
| * mark_page_lazyfree() moves @page to the inactive file list. |
| * This is done to accelerate the reclaim of @page. |
| */ |
| void mark_page_lazyfree(struct page *page) |
| { |
| if (PageLRU(page) && PageAnon(page) && PageSwapBacked(page) && |
| !PageSwapCache(page) && !PageUnevictable(page)) { |
| struct pagevec *pvec; |
| |
| local_lock(&lru_pvecs.lock); |
| pvec = this_cpu_ptr(&lru_pvecs.lru_lazyfree); |
| get_page(page); |
| if (!pagevec_add(pvec, page) || PageCompound(page)) |
| pagevec_lru_move_fn(pvec, lru_lazyfree_fn, NULL); |
| local_unlock(&lru_pvecs.lock); |
| } |
| } |
| |
| void lru_add_drain(void) |
| { |
| local_lock(&lru_pvecs.lock); |
| lru_add_drain_cpu(smp_processor_id()); |
| local_unlock(&lru_pvecs.lock); |
| } |
| |
| void lru_add_drain_cpu_zone(struct zone *zone) |
| { |
| local_lock(&lru_pvecs.lock); |
| lru_add_drain_cpu(smp_processor_id()); |
| drain_local_pages(zone); |
| local_unlock(&lru_pvecs.lock); |
| } |
| |
| #ifdef CONFIG_SMP |
| |
| static DEFINE_PER_CPU(struct work_struct, lru_add_drain_work); |
| |
| static void lru_add_drain_per_cpu(struct work_struct *dummy) |
| { |
| lru_add_drain(); |
| } |
| |
| /* |
| * Doesn't need any cpu hotplug locking because we do rely on per-cpu |
| * kworkers being shut down before our page_alloc_cpu_dead callback is |
| * executed on the offlined cpu. |
| * Calling this function with cpu hotplug locks held can actually lead |
| * to obscure indirect dependencies via WQ context. |
| */ |
| void lru_add_drain_all(void) |
| { |
| static seqcount_t seqcount = SEQCNT_ZERO(seqcount); |
| static DEFINE_MUTEX(lock); |
| static struct cpumask has_work; |
| int cpu, seq; |
| |
| /* |
| * Make sure nobody triggers this path before mm_percpu_wq is fully |
| * initialized. |
| */ |
| if (WARN_ON(!mm_percpu_wq)) |
| return; |
| |
| seq = raw_read_seqcount_latch(&seqcount); |
| |
| mutex_lock(&lock); |
| |
| /* |
| * Piggyback on drain started and finished while we waited for lock: |
| * all pages pended at the time of our enter were drained from vectors. |
| */ |
| if (__read_seqcount_retry(&seqcount, seq)) |
| goto done; |
| |
| raw_write_seqcount_latch(&seqcount); |
| |
| cpumask_clear(&has_work); |
| |
| for_each_online_cpu(cpu) { |
| struct work_struct *work = &per_cpu(lru_add_drain_work, cpu); |
| |
| if (pagevec_count(&per_cpu(lru_pvecs.lru_add, cpu)) || |
| pagevec_count(&per_cpu(lru_rotate.pvec, cpu)) || |
| pagevec_count(&per_cpu(lru_pvecs.lru_deactivate_file, cpu)) || |
| pagevec_count(&per_cpu(lru_pvecs.lru_deactivate, cpu)) || |
| pagevec_count(&per_cpu(lru_pvecs.lru_lazyfree, cpu)) || |
| need_activate_page_drain(cpu)) { |
| INIT_WORK(work, lru_add_drain_per_cpu); |
| queue_work_on(cpu, mm_percpu_wq, work); |
| cpumask_set_cpu(cpu, &has_work); |
| } |
| } |
| |
| for_each_cpu(cpu, &has_work) |
| flush_work(&per_cpu(lru_add_drain_work, cpu)); |
| |
| done: |
| mutex_unlock(&lock); |
| } |
| #else |
| void lru_add_drain_all(void) |
| { |
| lru_add_drain(); |
| } |
| #endif |
| |
| /** |
| * release_pages - batched put_page() |
| * @pages: array of pages to release |
| * @nr: number of pages |
| * |
| * Decrement the reference count on all the pages in @pages. If it |
| * fell to zero, remove the page from the LRU and free it. |
| */ |
| void release_pages(struct page **pages, int nr) |
| { |
| int i; |
| LIST_HEAD(pages_to_free); |
| struct pglist_data *locked_pgdat = NULL; |
| struct lruvec *lruvec; |
| unsigned long uninitialized_var(flags); |
| unsigned int uninitialized_var(lock_batch); |
| |
| for (i = 0; i < nr; i++) { |
| struct page *page = pages[i]; |
| |
| /* |
| * Make sure the IRQ-safe lock-holding time does not get |
| * excessive with a continuous string of pages from the |
| * same pgdat. The lock is held only if pgdat != NULL. |
| */ |
| if (locked_pgdat && ++lock_batch == SWAP_CLUSTER_MAX) { |
| spin_unlock_irqrestore(&locked_pgdat->lru_lock, flags); |
| locked_pgdat = NULL; |
| } |
| |
| if (is_huge_zero_page(page)) |
| continue; |
| |
| if (is_zone_device_page(page)) { |
| if (locked_pgdat) { |
| spin_unlock_irqrestore(&locked_pgdat->lru_lock, |
| flags); |
| locked_pgdat = NULL; |
| } |
| /* |
| * ZONE_DEVICE pages that return 'false' from |
| * put_devmap_managed_page() do not require special |
| * processing, and instead, expect a call to |
| * put_page_testzero(). |
| */ |
| if (page_is_devmap_managed(page)) { |
| put_devmap_managed_page(page); |
| continue; |
| } |
| } |
| |
| page = compound_head(page); |
| if (!put_page_testzero(page)) |
| continue; |
| |
| if (PageCompound(page)) { |
| if (locked_pgdat) { |
| spin_unlock_irqrestore(&locked_pgdat->lru_lock, flags); |
| locked_pgdat = NULL; |
| } |
| __put_compound_page(page); |
| continue; |
| } |
| |
| if (PageLRU(page)) { |
| struct pglist_data *pgdat = page_pgdat(page); |
| |
| if (pgdat != locked_pgdat) { |
| if (locked_pgdat) |
| spin_unlock_irqrestore(&locked_pgdat->lru_lock, |
| flags); |
| lock_batch = 0; |
| locked_pgdat = pgdat; |
| spin_lock_irqsave(&locked_pgdat->lru_lock, flags); |
| } |
| |
| lruvec = mem_cgroup_page_lruvec(page, locked_pgdat); |
| VM_BUG_ON_PAGE(!PageLRU(page), page); |
| __ClearPageLRU(page); |
| del_page_from_lru_list(page, lruvec, page_off_lru(page)); |
| } |
| |
| /* Clear Active bit in case of parallel mark_page_accessed */ |
| __ClearPageActive(page); |
| __ClearPageWaiters(page); |
| |
| list_add(&page->lru, &pages_to_free); |
| } |
| if (locked_pgdat) |
| spin_unlock_irqrestore(&locked_pgdat->lru_lock, flags); |
| |
| mem_cgroup_uncharge_list(&pages_to_free); |
| free_unref_page_list(&pages_to_free); |
| } |
| EXPORT_SYMBOL(release_pages); |
| |
| /* |
| * The pages which we're about to release may be in the deferred lru-addition |
| * queues. That would prevent them from really being freed right now. That's |
| * OK from a correctness point of view but is inefficient - those pages may be |
| * cache-warm and we want to give them back to the page allocator ASAP. |
| * |
| * So __pagevec_release() will drain those queues here. __pagevec_lru_add() |
| * and __pagevec_lru_add_active() call release_pages() directly to avoid |
| * mutual recursion. |
| */ |
| void __pagevec_release(struct pagevec *pvec) |
| { |
| if (!pvec->percpu_pvec_drained) { |
| lru_add_drain(); |
| pvec->percpu_pvec_drained = true; |
| } |
| release_pages(pvec->pages, pagevec_count(pvec)); |
| pagevec_reinit(pvec); |
| } |
| EXPORT_SYMBOL(__pagevec_release); |
| |
| #ifdef CONFIG_TRANSPARENT_HUGEPAGE |
| /* used by __split_huge_page_refcount() */ |
| void lru_add_page_tail(struct page *page, struct page *page_tail, |
| struct lruvec *lruvec, struct list_head *list) |
| { |
| const int file = 0; |
| |
| VM_BUG_ON_PAGE(!PageHead(page), page); |
| VM_BUG_ON_PAGE(PageCompound(page_tail), page); |
| VM_BUG_ON_PAGE(PageLRU(page_tail), page); |
| lockdep_assert_held(&lruvec_pgdat(lruvec)->lru_lock); |
| |
| if (!list) |
| SetPageLRU(page_tail); |
| |
| if (likely(PageLRU(page))) |
| list_add_tail(&page_tail->lru, &page->lru); |
| else if (list) { |
| /* page reclaim is reclaiming a huge page */ |
| get_page(page_tail); |
| list_add_tail(&page_tail->lru, list); |
| } else { |
| /* |
| * Head page has not yet been counted, as an hpage, |
| * so we must account for each subpage individually. |
| * |
| * Put page_tail on the list at the correct position |
| * so they all end up in order. |
| */ |
| add_page_to_lru_list_tail(page_tail, lruvec, |
| page_lru(page_tail)); |
| } |
| |
| if (!PageUnevictable(page)) |
| update_page_reclaim_stat(lruvec, file, PageActive(page_tail)); |
| } |
| #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ |
| |
| static void __pagevec_lru_add_fn(struct page *page, struct lruvec *lruvec, |
| void *arg) |
| { |
| enum lru_list lru; |
| int was_unevictable = TestClearPageUnevictable(page); |
| |
| VM_BUG_ON_PAGE(PageLRU(page), page); |
| |
| /* |
| * Page becomes evictable in two ways: |
| * 1) Within LRU lock [munlock_vma_page() and __munlock_pagevec()]. |
| * 2) Before acquiring LRU lock to put the page to correct LRU and then |
| * a) do PageLRU check with lock [check_move_unevictable_pages] |
| * b) do PageLRU check before lock [clear_page_mlock] |
| * |
| * (1) & (2a) are ok as LRU lock will serialize them. For (2b), we need |
| * following strict ordering: |
| * |
| * #0: __pagevec_lru_add_fn #1: clear_page_mlock |
| * |
| * SetPageLRU() TestClearPageMlocked() |
| * smp_mb() // explicit ordering // above provides strict |
| * // ordering |
| * PageMlocked() PageLRU() |
| * |
| * |
| * if '#1' does not observe setting of PG_lru by '#0' and fails |
| * isolation, the explicit barrier will make sure that page_evictable |
| * check will put the page in correct LRU. Without smp_mb(), SetPageLRU |
| * can be reordered after PageMlocked check and can make '#1' to fail |
| * the isolation of the page whose Mlocked bit is cleared (#0 is also |
| * looking at the same page) and the evictable page will be stranded |
| * in an unevictable LRU. |
| */ |
| SetPageLRU(page); |
| smp_mb__after_atomic(); |
| |
| if (page_evictable(page)) { |
| lru = page_lru(page); |
| update_page_reclaim_stat(lruvec, page_is_file_lru(page), |
| PageActive(page)); |
| if (was_unevictable) |
| count_vm_event(UNEVICTABLE_PGRESCUED); |
| } else { |
| lru = LRU_UNEVICTABLE; |
| ClearPageActive(page); |
| SetPageUnevictable(page); |
| if (!was_unevictable) |
| count_vm_event(UNEVICTABLE_PGCULLED); |
| } |
| |
| add_page_to_lru_list(page, lruvec, lru); |
| trace_mm_lru_insertion(page, lru); |
| } |
| |
| /* |
| * Add the passed pages to the LRU, then drop the caller's refcount |
| * on them. Reinitialises the caller's pagevec. |
| */ |
| void __pagevec_lru_add(struct pagevec *pvec) |
| { |
| pagevec_lru_move_fn(pvec, __pagevec_lru_add_fn, NULL); |
| } |
| |
| /** |
| * pagevec_lookup_entries - gang pagecache lookup |
| * @pvec: Where the resulting entries are placed |
| * @mapping: The address_space to search |
| * @start: The starting entry index |
| * @nr_entries: The maximum number of pages |
| * @indices: The cache indices corresponding to the entries in @pvec |
| * |
| * pagevec_lookup_entries() will search for and return a group of up |
| * to @nr_pages pages and shadow entries in the mapping. All |
| * entries are placed in @pvec. pagevec_lookup_entries() takes a |
| * reference against actual pages in @pvec. |
| * |
| * The search returns a group of mapping-contiguous entries with |
| * ascending indexes. There may be holes in the indices due to |
| * not-present entries. |
| * |
| * Only one subpage of a Transparent Huge Page is returned in one call: |
| * allowing truncate_inode_pages_range() to evict the whole THP without |
| * cycling through a pagevec of extra references. |
| * |
| * pagevec_lookup_entries() returns the number of entries which were |
| * found. |
| */ |
| unsigned pagevec_lookup_entries(struct pagevec *pvec, |
| struct address_space *mapping, |
| pgoff_t start, unsigned nr_entries, |
| pgoff_t *indices) |
| { |
| pvec->nr = find_get_entries(mapping, start, nr_entries, |
| pvec->pages, indices); |
| return pagevec_count(pvec); |
| } |
| |
| /** |
| * pagevec_remove_exceptionals - pagevec exceptionals pruning |
| * @pvec: The pagevec to prune |
| * |
| * pagevec_lookup_entries() fills both pages and exceptional radix |
| * tree entries into the pagevec. This function prunes all |
| * exceptionals from @pvec without leaving holes, so that it can be |
| * passed on to page-only pagevec operations. |
| */ |
| void pagevec_remove_exceptionals(struct pagevec *pvec) |
| { |
| int i, j; |
| |
| for (i = 0, j = 0; i < pagevec_count(pvec); i++) { |
| struct page *page = pvec->pages[i]; |
| if (!xa_is_value(page)) |
| pvec->pages[j++] = page; |
| } |
| pvec->nr = j; |
| } |
| |
| /** |
| * pagevec_lookup_range - gang pagecache lookup |
| * @pvec: Where the resulting pages are placed |
| * @mapping: The address_space to search |
| * @start: The starting page index |
| * @end: The final page index |
| * |
| * pagevec_lookup_range() will search for & return a group of up to PAGEVEC_SIZE |
| * pages in the mapping starting from index @start and upto index @end |
| * (inclusive). The pages are placed in @pvec. pagevec_lookup() takes a |
| * reference against the pages in @pvec. |
| * |
| * The search returns a group of mapping-contiguous pages with ascending |
| * indexes. There may be holes in the indices due to not-present pages. We |
| * also update @start to index the next page for the traversal. |
| * |
| * pagevec_lookup_range() returns the number of pages which were found. If this |
| * number is smaller than PAGEVEC_SIZE, the end of specified range has been |
| * reached. |
| */ |
| unsigned pagevec_lookup_range(struct pagevec *pvec, |
| struct address_space *mapping, pgoff_t *start, pgoff_t end) |
| { |
| pvec->nr = find_get_pages_range(mapping, start, end, PAGEVEC_SIZE, |
| pvec->pages); |
| return pagevec_count(pvec); |
| } |
| EXPORT_SYMBOL(pagevec_lookup_range); |
| |
| unsigned pagevec_lookup_range_tag(struct pagevec *pvec, |
| struct address_space *mapping, pgoff_t *index, pgoff_t end, |
| xa_mark_t tag) |
| { |
| pvec->nr = find_get_pages_range_tag(mapping, index, end, tag, |
| PAGEVEC_SIZE, pvec->pages); |
| return pagevec_count(pvec); |
| } |
| EXPORT_SYMBOL(pagevec_lookup_range_tag); |
| |
| unsigned pagevec_lookup_range_nr_tag(struct pagevec *pvec, |
| struct address_space *mapping, pgoff_t *index, pgoff_t end, |
| xa_mark_t tag, unsigned max_pages) |
| { |
| pvec->nr = find_get_pages_range_tag(mapping, index, end, tag, |
| min_t(unsigned int, max_pages, PAGEVEC_SIZE), pvec->pages); |
| return pagevec_count(pvec); |
| } |
| EXPORT_SYMBOL(pagevec_lookup_range_nr_tag); |
| /* |
| * Perform any setup for the swap system |
| */ |
| void __init swap_setup(void) |
| { |
| unsigned long megs = totalram_pages() >> (20 - PAGE_SHIFT); |
| |
| /* Use a smaller cluster for small-memory machines */ |
| if (megs < 16) |
| page_cluster = 2; |
| else |
| page_cluster = 3; |
| /* |
| * Right now other parts of the system means that we |
| * _really_ don't want to cluster much more |
| */ |
| } |
| |
| #ifdef CONFIG_DEV_PAGEMAP_OPS |
| void put_devmap_managed_page(struct page *page) |
| { |
| int count; |
| |
| if (WARN_ON_ONCE(!page_is_devmap_managed(page))) |
| return; |
| |
| count = page_ref_dec_return(page); |
| |
| /* |
| * devmap page refcounts are 1-based, rather than 0-based: if |
| * refcount is 1, then the page is free and the refcount is |
| * stable because nobody holds a reference on the page. |
| */ |
| if (count == 1) |
| free_devmap_managed_page(page); |
| else if (!count) |
| __put_page(page); |
| } |
| EXPORT_SYMBOL(put_devmap_managed_page); |
| #endif |