![Kirill A. Shutemov](/assets/img/avatar_default.png)
Andrea has found[1] a race condition on MMU-gather based TLB flush vs split_huge_page() or shrinker which frees huge zero under us (patch 1/2 and 2/2 respectively). With new THP refcounting, we don't need patch 1/2: mmu_gather keeps the page pinned until flush is complete and the pin prevents the page from being split under us. We still need patch 2/2. This is simplified version of Andrea's patch. We don't need fancy encoding. [1] http://lkml.kernel.org/r/1447938052-22165-1-git-send-email-aarcange@redhat.com Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reported-by: Andrea Arcangeli <aarcange@redhat.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
971 lines
26 KiB
C
971 lines
26 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/memremap.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 <linux/uio.h>
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#include <linux/hugetlb.h>
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#include <linux/page_idle.h>
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#include "internal.h"
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#define CREATE_TRACE_POINTS
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#include <trace/events/pagemap.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, lru_add_pvec);
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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_file_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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struct zone *zone = page_zone(page);
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struct lruvec *lruvec;
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unsigned long flags;
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spin_lock_irqsave(&zone->lru_lock, flags);
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lruvec = mem_cgroup_page_lruvec(page, zone);
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VM_BUG_ON_PAGE(!PageLRU(page), page);
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__ClearPageLRU(page);
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del_page_from_lru_list(page, lruvec, page_off_lru(page));
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spin_unlock_irqrestore(&zone->lru_lock, flags);
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}
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mem_cgroup_uncharge(page);
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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, false);
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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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/*
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* __page_cache_release() is supposed to be called for thp, not for
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* hugetlb. This is because hugetlb page does never have PageLRU set
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* (it's never listed to any LRU lists) and no memcg routines should
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* be called for hugetlb (it has a separate hugetlb_cgroup.)
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*/
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if (!PageHuge(page))
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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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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
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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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* 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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put_page(victim);
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}
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}
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EXPORT_SYMBOL(put_pages_list);
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/*
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* get_kernel_pages() - pin kernel pages in memory
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* @kiov: An array of struct kvec structures
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* @nr_segs: number of segments to pin
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* @write: pinning for read/write, currently ignored
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* @pages: array that receives pointers to the pages pinned.
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* Should be at least nr_segs long.
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*
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* Returns number of pages pinned. This may be fewer than the number
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* requested. If nr_pages is 0 or negative, returns 0. If no pages
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* were pinned, returns -errno. Each page returned must be released
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* with a put_page() call when it is finished with.
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*/
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int get_kernel_pages(const struct kvec *kiov, int nr_segs, int write,
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struct page **pages)
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{
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int seg;
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for (seg = 0; seg < nr_segs; seg++) {
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if (WARN_ON(kiov[seg].iov_len != PAGE_SIZE))
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return seg;
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pages[seg] = kmap_to_page(kiov[seg].iov_base);
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get_page(pages[seg]);
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}
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return seg;
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}
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EXPORT_SYMBOL_GPL(get_kernel_pages);
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/*
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* get_kernel_page() - pin a kernel page in memory
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* @start: starting kernel address
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* @write: pinning for read/write, currently ignored
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* @pages: array that receives pointer to the page pinned.
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* Must be at least nr_segs long.
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*
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* Returns 1 if page is pinned. If the page was not pinned, returns
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* -errno. The page returned must be released with a put_page() call
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* when it is finished with.
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*/
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int get_kernel_page(unsigned long start, int write, struct page **pages)
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{
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const struct kvec kiov = {
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.iov_base = (void *)start,
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.iov_len = PAGE_SIZE
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};
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return get_kernel_pages(&kiov, 1, write, pages);
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}
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EXPORT_SYMBOL_GPL(get_kernel_page);
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static void pagevec_lru_move_fn(struct pagevec *pvec,
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void (*move_fn)(struct page *page, struct lruvec *lruvec, 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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struct lruvec *lruvec;
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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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lruvec = mem_cgroup_page_lruvec(page, zone);
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(*move_fn)(page, lruvec, 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, struct lruvec *lruvec,
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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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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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get_page(page);
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local_irq_save(flags);
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pvec = this_cpu_ptr(&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 lruvec *lruvec,
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int file, int rotated)
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{
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struct zone_reclaim_stat *reclaim_stat = &lruvec->reclaim_stat;
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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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}
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static void __activate_page(struct page *page, struct lruvec *lruvec,
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void *arg)
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{
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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(page, lruvec, lru);
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SetPageActive(page);
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lru += LRU_ACTIVE;
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add_page_to_lru_list(page, lruvec, lru);
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trace_mm_lru_activate(page);
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__count_vm_event(PGACTIVATE);
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update_page_reclaim_stat(lruvec, 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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static bool need_activate_page_drain(int cpu)
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{
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return pagevec_count(&per_cpu(activate_page_pvecs, cpu)) != 0;
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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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get_page(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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static bool need_activate_page_drain(int cpu)
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{
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return false;
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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, mem_cgroup_page_lruvec(page, zone), NULL);
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spin_unlock_irq(&zone->lru_lock);
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}
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#endif
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static void __lru_cache_activate_page(struct page *page)
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{
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struct pagevec *pvec = &get_cpu_var(lru_add_pvec);
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int i;
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/*
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* Search backwards on the optimistic assumption that the page being
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* activated has just been added to this pagevec. Note that only
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* the local pagevec is examined as a !PageLRU page could be in the
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* process of being released, reclaimed, migrated or on a remote
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* pagevec that is currently being drained. Furthermore, marking
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* a remote pagevec's page PageActive potentially hits a race where
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* a page is marked PageActive just after it is added to the inactive
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* list causing accounting errors and BUG_ON checks to trigger.
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*/
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for (i = pagevec_count(pvec) - 1; i >= 0; i--) {
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struct page *pagevec_page = pvec->pages[i];
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if (pagevec_page == page) {
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SetPageActive(page);
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break;
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}
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}
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put_cpu_var(lru_add_pvec);
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}
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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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* When a newly allocated page is not yet visible, so safe for non-atomic ops,
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* __SetPageReferenced(page) may be substituted for mark_page_accessed(page).
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*/
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void mark_page_accessed(struct page *page)
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{
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page = compound_head(page);
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if (!PageActive(page) && !PageUnevictable(page) &&
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PageReferenced(page)) {
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/*
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* If the page is on the LRU, queue it for activation via
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* activate_page_pvecs. Otherwise, assume the page is on a
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* pagevec, mark it active and it'll be moved to the active
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* LRU on the next drain.
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*/
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if (PageLRU(page))
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activate_page(page);
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else
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__lru_cache_activate_page(page);
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ClearPageReferenced(page);
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if (page_is_file_cache(page))
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workingset_activation(page);
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} else if (!PageReferenced(page)) {
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SetPageReferenced(page);
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}
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if (page_is_idle(page))
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clear_page_idle(page);
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}
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EXPORT_SYMBOL(mark_page_accessed);
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static void __lru_cache_add(struct page *page)
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{
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struct pagevec *pvec = &get_cpu_var(lru_add_pvec);
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get_page(page);
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if (!pagevec_space(pvec))
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__pagevec_lru_add(pvec);
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pagevec_add(pvec, page);
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put_cpu_var(lru_add_pvec);
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}
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/**
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* lru_cache_add: add a page to the page lists
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* @page: the page to add
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*/
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void lru_cache_add_anon(struct page *page)
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{
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if (PageActive(page))
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ClearPageActive(page);
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__lru_cache_add(page);
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}
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void lru_cache_add_file(struct page *page)
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{
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if (PageActive(page))
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ClearPageActive(page);
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__lru_cache_add(page);
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}
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EXPORT_SYMBOL(lru_cache_add_file);
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/**
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* lru_cache_add - add a page to a page list
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* @page: the page to be added to the LRU.
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*
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* Queue the page for addition to the LRU via pagevec. The decision on whether
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* to add the page to the [in]active [file|anon] list is deferred until the
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* pagevec is drained. This gives a chance for the caller of lru_cache_add()
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* have the page added to the active list using mark_page_accessed().
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*/
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void lru_cache_add(struct page *page)
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{
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VM_BUG_ON_PAGE(PageActive(page) && PageUnevictable(page), page);
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VM_BUG_ON_PAGE(PageLRU(page), page);
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__lru_cache_add(page);
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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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struct lruvec *lruvec;
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spin_lock_irq(&zone->lru_lock);
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lruvec = mem_cgroup_page_lruvec(page, zone);
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ClearPageActive(page);
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SetPageUnevictable(page);
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SetPageLRU(page);
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add_page_to_lru_list(page, lruvec, LRU_UNEVICTABLE);
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spin_unlock_irq(&zone->lru_lock);
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}
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/**
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* lru_cache_add_active_or_unevictable
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* @page: the page to be added to LRU
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* @vma: vma in which page is mapped for determining reclaimability
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*
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* Place @page on the active or unevictable LRU list, depending on its
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* evictability. Note that if the page is not evictable, it goes
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* directly back onto it's zone's unevictable list, it does NOT use a
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* per cpu pagevec.
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*/
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void lru_cache_add_active_or_unevictable(struct page *page,
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struct vm_area_struct *vma)
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{
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VM_BUG_ON_PAGE(PageLRU(page), page);
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if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED)) {
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SetPageActive(page);
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lru_cache_add(page);
|
|
return;
|
|
}
|
|
|
|
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);
|
|
}
|
|
add_page_to_unevictable_list(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_cache(page);
|
|
lru = page_lru_base_type(page);
|
|
|
|
del_page_from_lru_list(page, lruvec, lru + active);
|
|
ClearPageActive(page);
|
|
ClearPageReferenced(page);
|
|
add_page_to_lru_list(page, lruvec, lru);
|
|
|
|
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.
|
|
*/
|
|
SetPageReclaim(page);
|
|
} else {
|
|
/*
|
|
* The page's writeback ends up during pagevec
|
|
* We moves tha page into tail of inactive.
|
|
*/
|
|
list_move_tail(&page->lru, &lruvec->lists[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_cache(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_event(PGDEACTIVATE);
|
|
update_page_reclaim_stat(lruvec, 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 *pvec = &per_cpu(lru_add_pvec, cpu);
|
|
|
|
if (pagevec_count(pvec))
|
|
__pagevec_lru_add(pvec);
|
|
|
|
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_file_pvecs, cpu);
|
|
if (pagevec_count(pvec))
|
|
pagevec_lru_move_fn(pvec, lru_deactivate_file_fn, NULL);
|
|
|
|
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_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 = &get_cpu_var(lru_deactivate_file_pvecs);
|
|
|
|
if (!pagevec_add(pvec, page))
|
|
pagevec_lru_move_fn(pvec, lru_deactivate_file_fn, NULL);
|
|
put_cpu_var(lru_deactivate_file_pvecs);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* 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 = &get_cpu_var(lru_deactivate_pvecs);
|
|
|
|
get_page(page);
|
|
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();
|
|
}
|
|
|
|
static DEFINE_PER_CPU(struct work_struct, lru_add_drain_work);
|
|
|
|
void lru_add_drain_all(void)
|
|
{
|
|
static DEFINE_MUTEX(lock);
|
|
static struct cpumask has_work;
|
|
int cpu;
|
|
|
|
mutex_lock(&lock);
|
|
get_online_cpus();
|
|
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_add_pvec, cpu)) ||
|
|
pagevec_count(&per_cpu(lru_rotate_pvecs, cpu)) ||
|
|
pagevec_count(&per_cpu(lru_deactivate_file_pvecs, cpu)) ||
|
|
pagevec_count(&per_cpu(lru_deactivate_pvecs, cpu)) ||
|
|
need_activate_page_drain(cpu)) {
|
|
INIT_WORK(work, lru_add_drain_per_cpu);
|
|
schedule_work_on(cpu, work);
|
|
cpumask_set_cpu(cpu, &has_work);
|
|
}
|
|
}
|
|
|
|
for_each_cpu(cpu, &has_work)
|
|
flush_work(&per_cpu(lru_add_drain_work, cpu));
|
|
|
|
put_online_cpus();
|
|
mutex_unlock(&lock);
|
|
}
|
|
|
|
/**
|
|
* release_pages - batched put_page()
|
|
* @pages: array of pages to release
|
|
* @nr: number of pages
|
|
* @cold: whether the pages are cache cold
|
|
*
|
|
* 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, bool cold)
|
|
{
|
|
int i;
|
|
LIST_HEAD(pages_to_free);
|
|
struct zone *zone = 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 zone. The lock is held only if zone != NULL.
|
|
*/
|
|
if (zone && ++lock_batch == SWAP_CLUSTER_MAX) {
|
|
spin_unlock_irqrestore(&zone->lru_lock, flags);
|
|
zone = NULL;
|
|
}
|
|
|
|
if (is_huge_zero_page(page)) {
|
|
put_huge_zero_page();
|
|
continue;
|
|
}
|
|
|
|
page = compound_head(page);
|
|
if (!put_page_testzero(page))
|
|
continue;
|
|
|
|
if (PageCompound(page)) {
|
|
if (zone) {
|
|
spin_unlock_irqrestore(&zone->lru_lock, flags);
|
|
zone = NULL;
|
|
}
|
|
__put_compound_page(page);
|
|
continue;
|
|
}
|
|
|
|
if (PageLRU(page)) {
|
|
struct zone *pagezone = page_zone(page);
|
|
|
|
if (pagezone != zone) {
|
|
if (zone)
|
|
spin_unlock_irqrestore(&zone->lru_lock,
|
|
flags);
|
|
lock_batch = 0;
|
|
zone = pagezone;
|
|
spin_lock_irqsave(&zone->lru_lock, flags);
|
|
}
|
|
|
|
lruvec = mem_cgroup_page_lruvec(page, zone);
|
|
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);
|
|
|
|
list_add(&page->lru, &pages_to_free);
|
|
}
|
|
if (zone)
|
|
spin_unlock_irqrestore(&zone->lru_lock, flags);
|
|
|
|
mem_cgroup_uncharge_list(&pages_to_free);
|
|
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 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);
|
|
VM_BUG_ON(NR_CPUS != 1 &&
|
|
!spin_is_locked(&lruvec_zone(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 {
|
|
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(page_tail, lruvec, page_lru(page_tail));
|
|
list_head = page_tail->lru.prev;
|
|
list_move_tail(&page_tail->lru, list_head);
|
|
}
|
|
|
|
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)
|
|
{
|
|
int file = page_is_file_cache(page);
|
|
int active = PageActive(page);
|
|
enum lru_list lru = page_lru(page);
|
|
|
|
VM_BUG_ON_PAGE(PageLRU(page), page);
|
|
|
|
SetPageLRU(page);
|
|
add_page_to_lru_list(page, lruvec, lru);
|
|
update_page_reclaim_stat(lruvec, file, active);
|
|
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);
|
|
}
|
|
EXPORT_SYMBOL(__pagevec_lru_add);
|
|
|
|
/**
|
|
* 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 entries
|
|
* @indices: The cache indices corresponding to the entries in @pvec
|
|
*
|
|
* pagevec_lookup_entries() will search for and return a group of up
|
|
* to @nr_entries 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.
|
|
*
|
|
* 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_pages,
|
|
pgoff_t *indices)
|
|
{
|
|
pvec->nr = find_get_entries(mapping, start, nr_pages,
|
|
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 (!radix_tree_exceptional_entry(page))
|
|
pvec->pages[j++] = page;
|
|
}
|
|
pvec->nr = j;
|
|
}
|
|
|
|
/**
|
|
* 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
|
|
int i;
|
|
|
|
for (i = 0; i < MAX_SWAPFILES; i++)
|
|
spin_lock_init(&swapper_spaces[i].tree_lock);
|
|
#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
|
|
*/
|
|
}
|