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![Mel Gorman](/assets/img/avatar_default.png)
On NUMA machines, the administrator can configure zone_reclaim_mode that
is a more targetted form of direct reclaim. On machines with large NUMA
distances for example, a zone_reclaim_mode defaults to 1 meaning that
clean unmapped pages will be reclaimed if the zone watermarks are not
being met. The problem is that zone_reclaim() failing at all means the
zone gets marked full.
This can cause situations where a zone is usable, but is being skipped
because it has been considered full. Take a situation where a large tmpfs
mount is occuping a large percentage of memory overall. The pages do not
get cleaned or reclaimed by zone_reclaim(), but the zone gets marked full
and the zonelist cache considers them not worth trying in the future.
This patch makes zone_reclaim() return more fine-grained information about
what occured when zone_reclaim() failued. The zone only gets marked full
if it really is unreclaimable. If it's a case that the scan did not occur
or if enough pages were not reclaimed with the limited reclaim_mode, then
the zone is simply skipped.
There is a side-effect to this patch. Currently, if zone_reclaim()
successfully reclaimed SWAP_CLUSTER_MAX, an allocation attempt would go
ahead. With this patch applied, zone watermarks are rechecked after
zone_reclaim() does some work.
This bug was introduced by commit 9276b1bc96
("memory page_alloc zonelist caching speedup") way back in 2.6.19 when the
zonelist_cache was introduced. It was not intended that zone_reclaim()
aggressively consider the zone to be full when it failed as full direct
reclaim can still be an option. Due to the age of the bug, it should be
considered a -stable candidate.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: Wu Fengguang <fengguang.wu@intel.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
266 lines
7.3 KiB
C
266 lines
7.3 KiB
C
/* internal.h: mm/ internal definitions
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*
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* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#ifndef __MM_INTERNAL_H
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#define __MM_INTERNAL_H
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#include <linux/mm.h>
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void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma,
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unsigned long floor, unsigned long ceiling);
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static inline void set_page_count(struct page *page, int v)
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{
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atomic_set(&page->_count, v);
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}
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/*
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* Turn a non-refcounted page (->_count == 0) into refcounted with
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* a count of one.
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*/
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static inline void set_page_refcounted(struct page *page)
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{
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VM_BUG_ON(PageTail(page));
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VM_BUG_ON(atomic_read(&page->_count));
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set_page_count(page, 1);
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}
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static inline void __put_page(struct page *page)
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{
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atomic_dec(&page->_count);
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}
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/*
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* in mm/vmscan.c:
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*/
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extern int isolate_lru_page(struct page *page);
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extern void putback_lru_page(struct page *page);
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/*
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* in mm/page_alloc.c
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*/
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extern unsigned long highest_memmap_pfn;
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extern void __free_pages_bootmem(struct page *page, unsigned int order);
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extern void prep_compound_page(struct page *page, unsigned long order);
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/*
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* function for dealing with page's order in buddy system.
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* zone->lock is already acquired when we use these.
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* So, we don't need atomic page->flags operations here.
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*/
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static inline unsigned long page_order(struct page *page)
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{
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VM_BUG_ON(!PageBuddy(page));
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return page_private(page);
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}
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#ifdef CONFIG_HAVE_MLOCK
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extern long mlock_vma_pages_range(struct vm_area_struct *vma,
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unsigned long start, unsigned long end);
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extern void munlock_vma_pages_range(struct vm_area_struct *vma,
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unsigned long start, unsigned long end);
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static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
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{
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munlock_vma_pages_range(vma, vma->vm_start, vma->vm_end);
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}
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#endif
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/*
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* unevictable_migrate_page() called only from migrate_page_copy() to
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* migrate unevictable flag to new page.
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* Note that the old page has been isolated from the LRU lists at this
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* point so we don't need to worry about LRU statistics.
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*/
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static inline void unevictable_migrate_page(struct page *new, struct page *old)
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{
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if (TestClearPageUnevictable(old))
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SetPageUnevictable(new);
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}
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#ifdef CONFIG_HAVE_MLOCKED_PAGE_BIT
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/*
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* Called only in fault path via page_evictable() for a new page
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* to determine if it's being mapped into a LOCKED vma.
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* If so, mark page as mlocked.
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*/
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static inline int is_mlocked_vma(struct vm_area_struct *vma, struct page *page)
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{
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VM_BUG_ON(PageLRU(page));
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if (likely((vma->vm_flags & (VM_LOCKED | VM_SPECIAL)) != VM_LOCKED))
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return 0;
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if (!TestSetPageMlocked(page)) {
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inc_zone_page_state(page, NR_MLOCK);
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count_vm_event(UNEVICTABLE_PGMLOCKED);
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}
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return 1;
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}
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/*
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* must be called with vma's mmap_sem held for read, and page locked.
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*/
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extern void mlock_vma_page(struct page *page);
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/*
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* Clear the page's PageMlocked(). This can be useful in a situation where
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* we want to unconditionally remove a page from the pagecache -- e.g.,
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* on truncation or freeing.
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*
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* It is legal to call this function for any page, mlocked or not.
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* If called for a page that is still mapped by mlocked vmas, all we do
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* is revert to lazy LRU behaviour -- semantics are not broken.
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*/
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extern void __clear_page_mlock(struct page *page);
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static inline void clear_page_mlock(struct page *page)
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{
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if (unlikely(TestClearPageMlocked(page)))
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__clear_page_mlock(page);
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}
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/*
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* mlock_migrate_page - called only from migrate_page_copy() to
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* migrate the Mlocked page flag; update statistics.
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*/
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static inline void mlock_migrate_page(struct page *newpage, struct page *page)
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{
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if (TestClearPageMlocked(page)) {
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unsigned long flags;
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local_irq_save(flags);
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__dec_zone_page_state(page, NR_MLOCK);
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SetPageMlocked(newpage);
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__inc_zone_page_state(newpage, NR_MLOCK);
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local_irq_restore(flags);
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}
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}
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#else /* CONFIG_HAVE_MLOCKED_PAGE_BIT */
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static inline int is_mlocked_vma(struct vm_area_struct *v, struct page *p)
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{
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return 0;
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}
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static inline void clear_page_mlock(struct page *page) { }
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static inline void mlock_vma_page(struct page *page) { }
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static inline void mlock_migrate_page(struct page *new, struct page *old) { }
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#endif /* CONFIG_HAVE_MLOCKED_PAGE_BIT */
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/*
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* Return the mem_map entry representing the 'offset' subpage within
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* the maximally aligned gigantic page 'base'. Handle any discontiguity
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* in the mem_map at MAX_ORDER_NR_PAGES boundaries.
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*/
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static inline struct page *mem_map_offset(struct page *base, int offset)
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{
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if (unlikely(offset >= MAX_ORDER_NR_PAGES))
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return pfn_to_page(page_to_pfn(base) + offset);
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return base + offset;
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}
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/*
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* Iterator over all subpages withing the maximally aligned gigantic
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* page 'base'. Handle any discontiguity in the mem_map.
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*/
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static inline struct page *mem_map_next(struct page *iter,
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struct page *base, int offset)
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{
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if (unlikely((offset & (MAX_ORDER_NR_PAGES - 1)) == 0)) {
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unsigned long pfn = page_to_pfn(base) + offset;
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if (!pfn_valid(pfn))
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return NULL;
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return pfn_to_page(pfn);
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}
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return iter + 1;
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}
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/*
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* FLATMEM and DISCONTIGMEM configurations use alloc_bootmem_node,
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* so all functions starting at paging_init should be marked __init
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* in those cases. SPARSEMEM, however, allows for memory hotplug,
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* and alloc_bootmem_node is not used.
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*/
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#ifdef CONFIG_SPARSEMEM
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#define __paginginit __meminit
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#else
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#define __paginginit __init
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#endif
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/* Memory initialisation debug and verification */
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enum mminit_level {
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MMINIT_WARNING,
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MMINIT_VERIFY,
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MMINIT_TRACE
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};
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#ifdef CONFIG_DEBUG_MEMORY_INIT
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extern int mminit_loglevel;
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#define mminit_dprintk(level, prefix, fmt, arg...) \
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do { \
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if (level < mminit_loglevel) { \
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printk(level <= MMINIT_WARNING ? KERN_WARNING : KERN_DEBUG); \
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printk(KERN_CONT "mminit::" prefix " " fmt, ##arg); \
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} \
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} while (0)
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extern void mminit_verify_pageflags_layout(void);
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extern void mminit_verify_page_links(struct page *page,
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enum zone_type zone, unsigned long nid, unsigned long pfn);
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extern void mminit_verify_zonelist(void);
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#else
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static inline void mminit_dprintk(enum mminit_level level,
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const char *prefix, const char *fmt, ...)
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{
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}
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static inline void mminit_verify_pageflags_layout(void)
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{
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}
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static inline void mminit_verify_page_links(struct page *page,
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enum zone_type zone, unsigned long nid, unsigned long pfn)
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{
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}
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static inline void mminit_verify_zonelist(void)
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{
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}
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#endif /* CONFIG_DEBUG_MEMORY_INIT */
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/* mminit_validate_memmodel_limits is independent of CONFIG_DEBUG_MEMORY_INIT */
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#if defined(CONFIG_SPARSEMEM)
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extern void mminit_validate_memmodel_limits(unsigned long *start_pfn,
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unsigned long *end_pfn);
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#else
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static inline void mminit_validate_memmodel_limits(unsigned long *start_pfn,
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unsigned long *end_pfn)
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{
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}
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#endif /* CONFIG_SPARSEMEM */
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#define GUP_FLAGS_WRITE 0x1
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#define GUP_FLAGS_FORCE 0x2
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#define GUP_FLAGS_IGNORE_VMA_PERMISSIONS 0x4
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#define GUP_FLAGS_IGNORE_SIGKILL 0x8
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int __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
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unsigned long start, int len, int flags,
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struct page **pages, struct vm_area_struct **vmas);
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#define ZONE_RECLAIM_NOSCAN -2
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#define ZONE_RECLAIM_FULL -1
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#define ZONE_RECLAIM_SOME 0
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#define ZONE_RECLAIM_SUCCESS 1
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#endif
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