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![Konstantin Khlebnikov](/assets/img/avatar_default.png)
This cpu hotplug hook was accidentally removed in commit 00a62ce91e
("mm: fix Committed_AS underflow on large NR_CPUS environment")
The visible effect of this accident: some pages are borrowed in per-cpu
page-vectors. Truncate can deal with it, but these pages cannot be
reused while this cpu is offline. So this is like a temporary memory
leak.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Eric B Munson <ebmunson@us.ibm.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
784 lines
20 KiB
C
784 lines
20 KiB
C
/*
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* linux/mm/swap.c
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*
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* Copyright (C) 1991, 1992, 1993, 1994 Linus Torvalds
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*/
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/*
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* This file contains the default values for the operation of the
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* Linux VM subsystem. Fine-tuning documentation can be found in
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* Documentation/sysctl/vm.txt.
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* Started 18.12.91
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* Swap aging added 23.2.95, Stephen Tweedie.
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* Buffermem limits added 12.3.98, Rik van Riel.
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*/
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <linux/kernel_stat.h>
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#include <linux/swap.h>
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#include <linux/mman.h>
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#include <linux/pagemap.h>
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#include <linux/pagevec.h>
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#include <linux/init.h>
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#include <linux/export.h>
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#include <linux/mm_inline.h>
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#include <linux/percpu_counter.h>
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#include <linux/percpu.h>
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#include <linux/cpu.h>
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#include <linux/notifier.h>
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#include <linux/backing-dev.h>
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#include <linux/memcontrol.h>
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#include <linux/gfp.h>
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#include "internal.h"
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/* How many pages do we try to swap or page in/out together? */
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int page_cluster;
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static DEFINE_PER_CPU(struct pagevec[NR_LRU_LISTS], lru_add_pvecs);
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static DEFINE_PER_CPU(struct pagevec, lru_rotate_pvecs);
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static DEFINE_PER_CPU(struct pagevec, lru_deactivate_pvecs);
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/*
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* This path almost never happens for VM activity - pages are normally
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* freed via pagevecs. But it gets used by networking.
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*/
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static void __page_cache_release(struct page *page)
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{
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if (PageLRU(page)) {
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unsigned long flags;
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struct zone *zone = page_zone(page);
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spin_lock_irqsave(&zone->lru_lock, flags);
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VM_BUG_ON(!PageLRU(page));
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__ClearPageLRU(page);
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del_page_from_lru_list(zone, page, page_off_lru(page));
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spin_unlock_irqrestore(&zone->lru_lock, flags);
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}
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}
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static void __put_single_page(struct page *page)
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{
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__page_cache_release(page);
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free_hot_cold_page(page, 0);
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}
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static void __put_compound_page(struct page *page)
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{
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compound_page_dtor *dtor;
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__page_cache_release(page);
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dtor = get_compound_page_dtor(page);
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(*dtor)(page);
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}
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static void put_compound_page(struct page *page)
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{
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if (unlikely(PageTail(page))) {
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/* __split_huge_page_refcount can run under us */
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struct page *page_head = compound_trans_head(page);
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if (likely(page != page_head &&
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get_page_unless_zero(page_head))) {
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unsigned long flags;
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/*
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* page_head wasn't a dangling pointer but it
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* may not be a head page anymore by the time
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* we obtain the lock. That is ok as long as it
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* can't be freed from under us.
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*/
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flags = compound_lock_irqsave(page_head);
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if (unlikely(!PageTail(page))) {
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/* __split_huge_page_refcount run before us */
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compound_unlock_irqrestore(page_head, flags);
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VM_BUG_ON(PageHead(page_head));
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if (put_page_testzero(page_head))
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__put_single_page(page_head);
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out_put_single:
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if (put_page_testzero(page))
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__put_single_page(page);
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return;
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}
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VM_BUG_ON(page_head != page->first_page);
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/*
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* We can release the refcount taken by
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* get_page_unless_zero() now that
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* __split_huge_page_refcount() is blocked on
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* the compound_lock.
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*/
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if (put_page_testzero(page_head))
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VM_BUG_ON(1);
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/* __split_huge_page_refcount will wait now */
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VM_BUG_ON(page_mapcount(page) <= 0);
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atomic_dec(&page->_mapcount);
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VM_BUG_ON(atomic_read(&page_head->_count) <= 0);
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VM_BUG_ON(atomic_read(&page->_count) != 0);
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compound_unlock_irqrestore(page_head, flags);
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if (put_page_testzero(page_head)) {
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if (PageHead(page_head))
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__put_compound_page(page_head);
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else
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__put_single_page(page_head);
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}
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} else {
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/* page_head is a dangling pointer */
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VM_BUG_ON(PageTail(page));
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goto out_put_single;
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}
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} else if (put_page_testzero(page)) {
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if (PageHead(page))
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__put_compound_page(page);
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else
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__put_single_page(page);
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}
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}
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void put_page(struct page *page)
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{
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if (unlikely(PageCompound(page)))
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put_compound_page(page);
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else if (put_page_testzero(page))
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__put_single_page(page);
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}
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EXPORT_SYMBOL(put_page);
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/*
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* This function is exported but must not be called by anything other
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* than get_page(). It implements the slow path of get_page().
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*/
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bool __get_page_tail(struct page *page)
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{
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/*
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* This takes care of get_page() if run on a tail page
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* returned by one of the get_user_pages/follow_page variants.
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* get_user_pages/follow_page itself doesn't need the compound
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* lock because it runs __get_page_tail_foll() under the
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* proper PT lock that already serializes against
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* split_huge_page().
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*/
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unsigned long flags;
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bool got = false;
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struct page *page_head = compound_trans_head(page);
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if (likely(page != page_head && get_page_unless_zero(page_head))) {
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/*
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* page_head wasn't a dangling pointer but it
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* may not be a head page anymore by the time
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* we obtain the lock. That is ok as long as it
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* can't be freed from under us.
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*/
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flags = compound_lock_irqsave(page_head);
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/* here __split_huge_page_refcount won't run anymore */
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if (likely(PageTail(page))) {
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__get_page_tail_foll(page, false);
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got = true;
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}
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compound_unlock_irqrestore(page_head, flags);
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if (unlikely(!got))
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put_page(page_head);
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}
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return got;
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}
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EXPORT_SYMBOL(__get_page_tail);
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/**
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* put_pages_list() - release a list of pages
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* @pages: list of pages threaded on page->lru
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*
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* Release a list of pages which are strung together on page.lru. Currently
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* used by read_cache_pages() and related error recovery code.
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*/
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void put_pages_list(struct list_head *pages)
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{
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while (!list_empty(pages)) {
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struct page *victim;
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victim = list_entry(pages->prev, struct page, lru);
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list_del(&victim->lru);
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page_cache_release(victim);
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}
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}
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EXPORT_SYMBOL(put_pages_list);
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static void pagevec_lru_move_fn(struct pagevec *pvec,
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void (*move_fn)(struct page *page, void *arg),
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void *arg)
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{
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int i;
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struct zone *zone = NULL;
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unsigned long flags = 0;
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for (i = 0; i < pagevec_count(pvec); i++) {
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struct page *page = pvec->pages[i];
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struct zone *pagezone = page_zone(page);
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if (pagezone != zone) {
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if (zone)
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spin_unlock_irqrestore(&zone->lru_lock, flags);
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zone = pagezone;
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spin_lock_irqsave(&zone->lru_lock, flags);
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}
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(*move_fn)(page, arg);
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}
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if (zone)
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spin_unlock_irqrestore(&zone->lru_lock, flags);
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release_pages(pvec->pages, pvec->nr, pvec->cold);
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pagevec_reinit(pvec);
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}
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static void pagevec_move_tail_fn(struct page *page, void *arg)
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{
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int *pgmoved = arg;
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if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
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enum lru_list lru = page_lru_base_type(page);
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struct lruvec *lruvec;
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lruvec = mem_cgroup_lru_move_lists(page_zone(page),
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page, lru, lru);
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list_move_tail(&page->lru, &lruvec->lists[lru]);
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(*pgmoved)++;
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}
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}
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/*
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* pagevec_move_tail() must be called with IRQ disabled.
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* Otherwise this may cause nasty races.
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*/
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static void pagevec_move_tail(struct pagevec *pvec)
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{
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int pgmoved = 0;
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pagevec_lru_move_fn(pvec, pagevec_move_tail_fn, &pgmoved);
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__count_vm_events(PGROTATED, pgmoved);
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}
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/*
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* Writeback is about to end against a page which has been marked for immediate
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* reclaim. If it still appears to be reclaimable, move it to the tail of the
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* inactive list.
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*/
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void rotate_reclaimable_page(struct page *page)
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{
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if (!PageLocked(page) && !PageDirty(page) && !PageActive(page) &&
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!PageUnevictable(page) && PageLRU(page)) {
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struct pagevec *pvec;
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unsigned long flags;
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page_cache_get(page);
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local_irq_save(flags);
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pvec = &__get_cpu_var(lru_rotate_pvecs);
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if (!pagevec_add(pvec, page))
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pagevec_move_tail(pvec);
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local_irq_restore(flags);
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}
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}
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static void update_page_reclaim_stat(struct zone *zone, struct page *page,
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int file, int rotated)
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{
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struct zone_reclaim_stat *reclaim_stat = &zone->reclaim_stat;
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struct zone_reclaim_stat *memcg_reclaim_stat;
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memcg_reclaim_stat = mem_cgroup_get_reclaim_stat_from_page(page);
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reclaim_stat->recent_scanned[file]++;
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if (rotated)
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reclaim_stat->recent_rotated[file]++;
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if (!memcg_reclaim_stat)
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return;
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memcg_reclaim_stat->recent_scanned[file]++;
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if (rotated)
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memcg_reclaim_stat->recent_rotated[file]++;
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}
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static void __activate_page(struct page *page, void *arg)
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{
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struct zone *zone = page_zone(page);
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if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
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int file = page_is_file_cache(page);
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int lru = page_lru_base_type(page);
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del_page_from_lru_list(zone, page, lru);
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SetPageActive(page);
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lru += LRU_ACTIVE;
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add_page_to_lru_list(zone, page, lru);
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__count_vm_event(PGACTIVATE);
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update_page_reclaim_stat(zone, page, file, 1);
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}
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}
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#ifdef CONFIG_SMP
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static DEFINE_PER_CPU(struct pagevec, activate_page_pvecs);
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static void activate_page_drain(int cpu)
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{
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struct pagevec *pvec = &per_cpu(activate_page_pvecs, cpu);
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if (pagevec_count(pvec))
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pagevec_lru_move_fn(pvec, __activate_page, NULL);
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}
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void activate_page(struct page *page)
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{
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if (PageLRU(page) && !PageActive(page) && !PageUnevictable(page)) {
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struct pagevec *pvec = &get_cpu_var(activate_page_pvecs);
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page_cache_get(page);
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if (!pagevec_add(pvec, page))
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pagevec_lru_move_fn(pvec, __activate_page, NULL);
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put_cpu_var(activate_page_pvecs);
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}
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}
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#else
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static inline void activate_page_drain(int cpu)
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{
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}
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void activate_page(struct page *page)
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{
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struct zone *zone = page_zone(page);
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spin_lock_irq(&zone->lru_lock);
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__activate_page(page, NULL);
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spin_unlock_irq(&zone->lru_lock);
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}
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#endif
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/*
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* Mark a page as having seen activity.
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*
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* inactive,unreferenced -> inactive,referenced
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* inactive,referenced -> active,unreferenced
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* active,unreferenced -> active,referenced
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*/
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void mark_page_accessed(struct page *page)
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{
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if (!PageActive(page) && !PageUnevictable(page) &&
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PageReferenced(page) && PageLRU(page)) {
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activate_page(page);
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ClearPageReferenced(page);
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} else if (!PageReferenced(page)) {
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SetPageReferenced(page);
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}
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}
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EXPORT_SYMBOL(mark_page_accessed);
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void __lru_cache_add(struct page *page, enum lru_list lru)
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{
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struct pagevec *pvec = &get_cpu_var(lru_add_pvecs)[lru];
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page_cache_get(page);
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if (!pagevec_add(pvec, page))
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__pagevec_lru_add(pvec, lru);
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put_cpu_var(lru_add_pvecs);
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}
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EXPORT_SYMBOL(__lru_cache_add);
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/**
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* lru_cache_add_lru - add a page to a page list
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* @page: the page to be added to the LRU.
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* @lru: the LRU list to which the page is added.
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*/
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void lru_cache_add_lru(struct page *page, enum lru_list lru)
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{
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if (PageActive(page)) {
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VM_BUG_ON(PageUnevictable(page));
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ClearPageActive(page);
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} else if (PageUnevictable(page)) {
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VM_BUG_ON(PageActive(page));
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ClearPageUnevictable(page);
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}
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VM_BUG_ON(PageLRU(page) || PageActive(page) || PageUnevictable(page));
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__lru_cache_add(page, lru);
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}
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/**
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* add_page_to_unevictable_list - add a page to the unevictable list
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* @page: the page to be added to the unevictable list
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*
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* Add page directly to its zone's unevictable list. To avoid races with
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* tasks that might be making the page evictable, through eg. munlock,
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* munmap or exit, while it's not on the lru, we want to add the page
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* while it's locked or otherwise "invisible" to other tasks. This is
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* difficult to do when using the pagevec cache, so bypass that.
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*/
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void add_page_to_unevictable_list(struct page *page)
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{
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struct zone *zone = page_zone(page);
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spin_lock_irq(&zone->lru_lock);
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SetPageUnevictable(page);
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SetPageLRU(page);
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add_page_to_lru_list(zone, page, LRU_UNEVICTABLE);
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spin_unlock_irq(&zone->lru_lock);
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}
|
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|
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/*
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* If the page can not be invalidated, it is moved to the
|
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* inactive list to speed up its reclaim. It is moved to the
|
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* head of the list, rather than the tail, to give the flusher
|
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* threads some time to write it out, as this is much more
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* effective than the single-page writeout from reclaim.
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*
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* If the page isn't page_mapped and dirty/writeback, the page
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* could reclaim asap using PG_reclaim.
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*
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* 1. active, mapped page -> none
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* 2. active, dirty/writeback page -> inactive, head, PG_reclaim
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* 3. inactive, mapped page -> none
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* 4. inactive, dirty/writeback page -> inactive, head, PG_reclaim
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* 5. inactive, clean -> inactive, tail
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* 6. Others -> none
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*
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* In 4, why it moves inactive's head, the VM expects the page would
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* be write it out by flusher threads as this is much more effective
|
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* than the single-page writeout from reclaim.
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*/
|
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static void lru_deactivate_fn(struct page *page, void *arg)
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{
|
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int lru, file;
|
|
bool active;
|
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struct zone *zone = page_zone(page);
|
|
|
|
if (!PageLRU(page))
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return;
|
|
|
|
if (PageUnevictable(page))
|
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return;
|
|
|
|
/* Some processes are using the page */
|
|
if (page_mapped(page))
|
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return;
|
|
|
|
active = PageActive(page);
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|
|
|
file = page_is_file_cache(page);
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lru = page_lru_base_type(page);
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del_page_from_lru_list(zone, page, lru + active);
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ClearPageActive(page);
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ClearPageReferenced(page);
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add_page_to_lru_list(zone, page, lru);
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|
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if (PageWriteback(page) || PageDirty(page)) {
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/*
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* PG_reclaim could be raced with end_page_writeback
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* It can make readahead confusing. But race window
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|
* is _really_ small and it's non-critical problem.
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*/
|
|
SetPageReclaim(page);
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} else {
|
|
struct lruvec *lruvec;
|
|
/*
|
|
* The page's writeback ends up during pagevec
|
|
* We moves tha page into tail of inactive.
|
|
*/
|
|
lruvec = mem_cgroup_lru_move_lists(zone, page, lru, lru);
|
|
list_move_tail(&page->lru, &lruvec->lists[lru]);
|
|
__count_vm_event(PGROTATED);
|
|
}
|
|
|
|
if (active)
|
|
__count_vm_event(PGDEACTIVATE);
|
|
update_page_reclaim_stat(zone, page, file, 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 *pvecs = per_cpu(lru_add_pvecs, cpu);
|
|
struct pagevec *pvec;
|
|
int lru;
|
|
|
|
for_each_lru(lru) {
|
|
pvec = &pvecs[lru - LRU_BASE];
|
|
if (pagevec_count(pvec))
|
|
__pagevec_lru_add(pvec, lru);
|
|
}
|
|
|
|
pvec = &per_cpu(lru_rotate_pvecs, cpu);
|
|
if (pagevec_count(pvec)) {
|
|
unsigned long flags;
|
|
|
|
/* No harm done if a racing interrupt already did this */
|
|
local_irq_save(flags);
|
|
pagevec_move_tail(pvec);
|
|
local_irq_restore(flags);
|
|
}
|
|
|
|
pvec = &per_cpu(lru_deactivate_pvecs, cpu);
|
|
if (pagevec_count(pvec))
|
|
pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
|
|
|
|
activate_page_drain(cpu);
|
|
}
|
|
|
|
/**
|
|
* deactivate_page - forcefully deactivate a 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_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 = &get_cpu_var(lru_deactivate_pvecs);
|
|
|
|
if (!pagevec_add(pvec, page))
|
|
pagevec_lru_move_fn(pvec, lru_deactivate_fn, NULL);
|
|
put_cpu_var(lru_deactivate_pvecs);
|
|
}
|
|
}
|
|
|
|
void lru_add_drain(void)
|
|
{
|
|
lru_add_drain_cpu(get_cpu());
|
|
put_cpu();
|
|
}
|
|
|
|
static void lru_add_drain_per_cpu(struct work_struct *dummy)
|
|
{
|
|
lru_add_drain();
|
|
}
|
|
|
|
/*
|
|
* Returns 0 for success
|
|
*/
|
|
int lru_add_drain_all(void)
|
|
{
|
|
return schedule_on_each_cpu(lru_add_drain_per_cpu);
|
|
}
|
|
|
|
/*
|
|
* Batched page_cache_release(). Decrement the reference count on all the
|
|
* passed pages. If it fell to zero then remove the page from the LRU and
|
|
* free it.
|
|
*
|
|
* Avoid taking zone->lru_lock if possible, but if it is taken, retain it
|
|
* for the remainder of the operation.
|
|
*
|
|
* The locking in this function is against shrink_inactive_list(): we recheck
|
|
* the page count inside the lock to see whether shrink_inactive_list()
|
|
* grabbed the page via the LRU. If it did, give up: shrink_inactive_list()
|
|
* will free it.
|
|
*/
|
|
void release_pages(struct page **pages, int nr, int cold)
|
|
{
|
|
int i;
|
|
LIST_HEAD(pages_to_free);
|
|
struct zone *zone = NULL;
|
|
unsigned long uninitialized_var(flags);
|
|
|
|
for (i = 0; i < nr; i++) {
|
|
struct page *page = pages[i];
|
|
|
|
if (unlikely(PageCompound(page))) {
|
|
if (zone) {
|
|
spin_unlock_irqrestore(&zone->lru_lock, flags);
|
|
zone = NULL;
|
|
}
|
|
put_compound_page(page);
|
|
continue;
|
|
}
|
|
|
|
if (!put_page_testzero(page))
|
|
continue;
|
|
|
|
if (PageLRU(page)) {
|
|
struct zone *pagezone = page_zone(page);
|
|
|
|
if (pagezone != zone) {
|
|
if (zone)
|
|
spin_unlock_irqrestore(&zone->lru_lock,
|
|
flags);
|
|
zone = pagezone;
|
|
spin_lock_irqsave(&zone->lru_lock, flags);
|
|
}
|
|
VM_BUG_ON(!PageLRU(page));
|
|
__ClearPageLRU(page);
|
|
del_page_from_lru_list(zone, page, page_off_lru(page));
|
|
}
|
|
|
|
list_add(&page->lru, &pages_to_free);
|
|
}
|
|
if (zone)
|
|
spin_unlock_irqrestore(&zone->lru_lock, flags);
|
|
|
|
free_hot_cold_page_list(&pages_to_free, cold);
|
|
}
|
|
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)
|
|
{
|
|
lru_add_drain();
|
|
release_pages(pvec->pages, pagevec_count(pvec), pvec->cold);
|
|
pagevec_reinit(pvec);
|
|
}
|
|
EXPORT_SYMBOL(__pagevec_release);
|
|
|
|
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
|
|
/* used by __split_huge_page_refcount() */
|
|
void lru_add_page_tail(struct zone* zone,
|
|
struct page *page, struct page *page_tail)
|
|
{
|
|
int uninitialized_var(active);
|
|
enum lru_list lru;
|
|
const int file = 0;
|
|
|
|
VM_BUG_ON(!PageHead(page));
|
|
VM_BUG_ON(PageCompound(page_tail));
|
|
VM_BUG_ON(PageLRU(page_tail));
|
|
VM_BUG_ON(NR_CPUS != 1 && !spin_is_locked(&zone->lru_lock));
|
|
|
|
SetPageLRU(page_tail);
|
|
|
|
if (page_evictable(page_tail, NULL)) {
|
|
if (PageActive(page)) {
|
|
SetPageActive(page_tail);
|
|
active = 1;
|
|
lru = LRU_ACTIVE_ANON;
|
|
} else {
|
|
active = 0;
|
|
lru = LRU_INACTIVE_ANON;
|
|
}
|
|
} else {
|
|
SetPageUnevictable(page_tail);
|
|
lru = LRU_UNEVICTABLE;
|
|
}
|
|
|
|
if (likely(PageLRU(page)))
|
|
list_add_tail(&page_tail->lru, &page->lru);
|
|
else {
|
|
struct list_head *list_head;
|
|
/*
|
|
* Head page has not yet been counted, as an hpage,
|
|
* so we must account for each subpage individually.
|
|
*
|
|
* Use the standard add function to put page_tail on the list,
|
|
* but then correct its position so they all end up in order.
|
|
*/
|
|
add_page_to_lru_list(zone, page_tail, lru);
|
|
list_head = page_tail->lru.prev;
|
|
list_move_tail(&page_tail->lru, list_head);
|
|
}
|
|
|
|
if (!PageUnevictable(page))
|
|
update_page_reclaim_stat(zone, page_tail, file, active);
|
|
}
|
|
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
|
|
|
|
static void __pagevec_lru_add_fn(struct page *page, void *arg)
|
|
{
|
|
enum lru_list lru = (enum lru_list)arg;
|
|
struct zone *zone = page_zone(page);
|
|
int file = is_file_lru(lru);
|
|
int active = is_active_lru(lru);
|
|
|
|
VM_BUG_ON(PageActive(page));
|
|
VM_BUG_ON(PageUnevictable(page));
|
|
VM_BUG_ON(PageLRU(page));
|
|
|
|
SetPageLRU(page);
|
|
if (active)
|
|
SetPageActive(page);
|
|
add_page_to_lru_list(zone, page, lru);
|
|
update_page_reclaim_stat(zone, page, file, active);
|
|
}
|
|
|
|
/*
|
|
* 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, enum lru_list lru)
|
|
{
|
|
VM_BUG_ON(is_unevictable_lru(lru));
|
|
|
|
pagevec_lru_move_fn(pvec, __pagevec_lru_add_fn, (void *)lru);
|
|
}
|
|
EXPORT_SYMBOL(__pagevec_lru_add);
|
|
|
|
/**
|
|
* pagevec_lookup - gang pagecache lookup
|
|
* @pvec: Where the resulting pages are placed
|
|
* @mapping: The address_space to search
|
|
* @start: The starting page index
|
|
* @nr_pages: The maximum number of pages
|
|
*
|
|
* pagevec_lookup() will search for and return a group of up to @nr_pages pages
|
|
* in the mapping. 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.
|
|
*
|
|
* pagevec_lookup() returns the number of pages which were found.
|
|
*/
|
|
unsigned pagevec_lookup(struct pagevec *pvec, struct address_space *mapping,
|
|
pgoff_t start, unsigned nr_pages)
|
|
{
|
|
pvec->nr = find_get_pages(mapping, start, nr_pages, pvec->pages);
|
|
return pagevec_count(pvec);
|
|
}
|
|
EXPORT_SYMBOL(pagevec_lookup);
|
|
|
|
unsigned pagevec_lookup_tag(struct pagevec *pvec, struct address_space *mapping,
|
|
pgoff_t *index, int tag, unsigned nr_pages)
|
|
{
|
|
pvec->nr = find_get_pages_tag(mapping, index, tag,
|
|
nr_pages, pvec->pages);
|
|
return pagevec_count(pvec);
|
|
}
|
|
EXPORT_SYMBOL(pagevec_lookup_tag);
|
|
|
|
/*
|
|
* Perform any setup for the swap system
|
|
*/
|
|
void __init swap_setup(void)
|
|
{
|
|
unsigned long megs = totalram_pages >> (20 - PAGE_SHIFT);
|
|
|
|
#ifdef CONFIG_SWAP
|
|
bdi_init(swapper_space.backing_dev_info);
|
|
#endif
|
|
|
|
/* 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
|
|
*/
|
|
}
|