Release 4.11 mm/migrate.c

Directory: mm
/*
 * Memory Migration functionality - linux/mm/migrate.c
 *
 * Copyright (C) 2006 Silicon Graphics, Inc., Christoph Lameter
 *
 * Page migration was first developed in the context of the memory hotplug
 * project. The main authors of the migration code are:
 *
 * IWAMOTO Toshihiro <iwamoto@valinux.co.jp>
 * Hirokazu Takahashi <taka@valinux.co.jp>
 * Dave Hansen <haveblue@us.ibm.com>
 * Christoph Lameter
 */

#include <linux/migrate.h>
#include <linux/export.h>
#include <linux/swap.h>
#include <linux/swapops.h>
#include <linux/pagemap.h>
#include <linux/buffer_head.h>
#include <linux/mm_inline.h>
#include <linux/nsproxy.h>
#include <linux/pagevec.h>
#include <linux/ksm.h>
#include <linux/rmap.h>
#include <linux/topology.h>
#include <linux/cpu.h>
#include <linux/cpuset.h>
#include <linux/writeback.h>
#include <linux/mempolicy.h>
#include <linux/vmalloc.h>
#include <linux/security.h>
#include <linux/backing-dev.h>
#include <linux/compaction.h>
#include <linux/syscalls.h>
#include <linux/hugetlb.h>
#include <linux/hugetlb_cgroup.h>
#include <linux/gfp.h>
#include <linux/balloon_compaction.h>
#include <linux/mmu_notifier.h>
#include <linux/page_idle.h>
#include <linux/page_owner.h>
#include <linux/sched/mm.h>

#include <asm/tlbflush.h>


#define CREATE_TRACE_POINTS
#include <trace/events/migrate.h>

#include "internal.h"

/*
 * migrate_prep() needs to be called before we start compiling a list of pages
 * to be migrated using isolate_lru_page(). If scheduling work on other CPUs is
 * undesirable, use migrate_prep_local()
 */


int migrate_prep(void)
{
	/*
         * Clear the LRU lists so pages can be isolated.
         * Note that pages may be moved off the LRU after we have
         * drained them. Those pages will fail to migrate like other
         * pages that may be busy.
         */
	lru_add_drain_all();

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Christoph Lameter 11 78.57% 1 50.00%
Mel Gorman 3 21.43% 1 50.00%
Total 14 100.00% 2 100.00%

/* Do the necessary work of migrate_prep but not if it involves other CPUs */


int migrate_prep_local(void)
{
	lru_add_drain();

	return 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Mel Gorman 10 76.92% 1 50.00%
Christoph Lameter 3 23.08% 1 50.00%
Total 13 100.00% 2 100.00%



int isolate_movable_page(struct page *page, isolate_mode_t mode)
{
	struct address_space *mapping;

	/*
         * Avoid burning cycles with pages that are yet under __free_pages(),
         * or just got freed under us.
         *
         * In case we 'win' a race for a movable page being freed under us and
         * raise its refcount preventing __free_pages() from doing its job
         * the put_page() at the end of this block will take care of
         * release this page, thus avoiding a nasty leakage.
         */
	if (unlikely(!get_page_unless_zero(page)))
		goto out;

	/*
         * Check PageMovable before holding a PG_lock because page's owner
         * assumes anybody doesn't touch PG_lock of newly allocated page
         * so unconditionally grapping the lock ruins page's owner side.
         */
	if (unlikely(!__PageMovable(page)))
		goto out_putpage;
	/*
         * As movable pages are not isolated from LRU lists, concurrent
         * compaction threads can race against page migration functions
         * as well as race against the releasing a page.
         *
         * In order to avoid having an already isolated movable page
         * being (wrongly) re-isolated while it is under migration,
         * or to avoid attempting to isolate pages being released,
         * lets be sure we have the page lock
         * before proceeding with the movable page isolation steps.
         */
	if (unlikely(!trylock_page(page)))
		goto out_putpage;

	if (!PageMovable(page) || PageIsolated(page))
		goto out_no_isolated;

	mapping = page_mapping(page);
	VM_BUG_ON_PAGE(!mapping, page);

	if (!mapping->a_ops->isolate_page(page, mode))
		goto out_no_isolated;

	/* Driver shouldn't use PG_isolated bit of page->flags */
	WARN_ON_ONCE(PageIsolated(page));
	__SetPageIsolated(page);
	unlock_page(page);

	return 0;

out_no_isolated:
	unlock_page(page);
out_putpage:
	put_page(page);
out:
	return -EBUSY;
}

Contributors
Person Tokens Prop Commits CommitProp
MinChan Kim 149 97.39% 1 50.00%
Yisheng Xie 4 2.61% 1 50.00%
Total 153 100.00% 2 100.00%

/* It should be called on page which is PG_movable */


void putback_movable_page(struct page *page)
{
	struct address_space *mapping;

	VM_BUG_ON_PAGE(!PageLocked(page), page);
	VM_BUG_ON_PAGE(!PageMovable(page), page);
	VM_BUG_ON_PAGE(!PageIsolated(page), page);

	mapping = page_mapping(page);
	mapping->a_ops->putback_page(page);
	__ClearPageIsolated(page);
}

Contributors
Person Tokens Prop Commits CommitProp
MinChan Kim 69 100.00% 1 100.00%
Total 69 100.00% 1 100.00%

/*
 * Put previously isolated pages back onto the appropriate lists
 * from where they were once taken off for compaction/migration.
 *
 * This function shall be used whenever the isolated pageset has been
 * built from lru, balloon, hugetlbfs page. See isolate_migratepages_range()
 * and isolate_huge_page().
 */


void putback_movable_pages(struct list_head *l)
{
	struct page *page;
	struct page *page2;

	list_for_each_entry_safe(page, page2, l, lru) {
		if (unlikely(PageHuge(page))) {
			putback_active_hugepage(page);
			continue;
		}
		list_del(&page->lru);
		/*
                 * We isolated non-lru movable page so here we can use
                 * __PageMovable because LRU page's mapping cannot have
                 * PAGE_MAPPING_MOVABLE.
                 */
		if (unlikely(__PageMovable(page))) {
			VM_BUG_ON_PAGE(!PageIsolated(page), page);
			lock_page(page);
			if (PageMovable(page))
				putback_movable_page(page);
			else
				__ClearPageIsolated(page);
			unlock_page(page);
			put_page(page);
		} else {
			dec_node_page_state(page, NR_ISOLATED_ANON +
					page_is_file_cache(page));
			putback_lru_page(page);
		}
	}
}

Contributors
Person Tokens Prop Commits CommitProp
MinChan Kim 59 43.70% 1 12.50%
Rafael Aquini 22 16.30% 2 25.00%
Christoph Lameter 19 14.07% 2 25.00%
Naoya Horiguchi 18 13.33% 1 12.50%
Lin Ming 12 8.89% 1 12.50%
Rabin Vincent 5 3.70% 1 12.50%
Total 135 100.00% 8 100.00%

/*
 * Restore a potential migration pte to a working pte entry
 */


static int remove_migration_pte(struct page *page, struct vm_area_struct *vma,
				 unsigned long addr, void *old)
{
	struct page_vma_mapped_walk pvmw = {
		.page = old,
		.vma = vma,
		.address = addr,
		.flags = PVMW_SYNC | PVMW_MIGRATION,
        };
	struct page *new;
	pte_t pte;
	swp_entry_t entry;

	VM_BUG_ON_PAGE(PageTail(page), page);
	while (page_vma_mapped_walk(&pvmw)) {
		if (PageKsm(page))
			new = page;
		else
			new = page - pvmw.page->index +
				linear_page_index(vma, pvmw.address);

		get_page(new);
		pte = pte_mkold(mk_pte(new, READ_ONCE(vma->vm_page_prot)));
		if (pte_swp_soft_dirty(*pvmw.pte))
			pte = pte_mksoft_dirty(pte);

		/*
                 * Recheck VMA as permissions can change since migration started
                 */
		entry = pte_to_swp_entry(*pvmw.pte);
		if (is_write_migration_entry(entry))
			pte = maybe_mkwrite(pte, vma);

#ifdef CONFIG_HUGETLB_PAGE
		if (PageHuge(new)) {
			pte = pte_mkhuge(pte);
			pte = arch_make_huge_pte(pte, vma, new, 0);
		}
#endif
		flush_dcache_page(new);
		set_pte_at(vma->vm_mm, pvmw.address, pvmw.pte, pte);

		if (PageHuge(new)) {
			if (PageAnon(new))
				hugepage_add_anon_rmap(new, vma, pvmw.address);
			else
				page_dup_rmap(new, true);
		} else if (PageAnon(new))
			page_add_anon_rmap(new, vma, pvmw.address, false);
		else
			page_add_file_rmap(new, false);

		if (vma->vm_flags & VM_LOCKED && !PageTransCompound(new))
			mlock_vma_page(new);

		/* No need to invalidate - it was non-present before */
		update_mmu_cache(vma, pvmw.address, pvmw.pte);
	}

	return SWAP_AGAIN;
}

Contributors
Person Tokens Prop Commits CommitProp
Kirill A. Shutemov 101 30.06% 5 26.32%
Christoph Lameter 99 29.46% 2 10.53%
Naoya Horiguchi 64 19.05% 2 10.53%
Hugh Dickins 26 7.74% 2 10.53%
Tony Lu 15 4.46% 1 5.26%
Cyrill V. Gorcunov 14 4.17% 1 5.26%
Andi Kleen 5 1.49% 1 5.26%
Andrea Arcangeli 4 1.19% 2 10.53%
Mel Gorman 3 0.89% 1 5.26%
Kamezawa Hiroyuki 3 0.89% 1 5.26%
Leonid Yegoshin 2 0.60% 1 5.26%
Total 336 100.00% 19 100.00%

/*
 * Get rid of all migration entries and replace them by
 * references to the indicated page.
 */


void remove_migration_ptes(struct page *old, struct page *new, bool locked)
{
	struct rmap_walk_control rwc = {
		.rmap_one = remove_migration_pte,
		.arg = old,
        };

	if (locked)
		rmap_walk_locked(new, &rwc);
	else
		rmap_walk(new, &rwc);
}

Contributors
Person Tokens Prop Commits CommitProp
Christoph Lameter 20 36.36% 1 25.00%
JoonSoo Kim 18 32.73% 1 25.00%
Kirill A. Shutemov 16 29.09% 1 25.00%
Hugh Dickins 1 1.82% 1 25.00%
Total 55 100.00% 4 100.00%

/*
 * Something used the pte of a page under migration. We need to
 * get to the page and wait until migration is finished.
 * When we return from this function the fault will be retried.
 */


void __migration_entry_wait(struct mm_struct *mm, pte_t *ptep,
				spinlock_t *ptl)
{
	pte_t pte;
	swp_entry_t entry;
	struct page *page;

	spin_lock(ptl);
	pte = *ptep;
	if (!is_swap_pte(pte))
		goto out;

	entry = pte_to_swp_entry(pte);
	if (!is_migration_entry(entry))
		goto out;

	page = migration_entry_to_page(entry);

	/*
         * Once radix-tree replacement of page migration started, page_count
         * *must* be zero. And, we don't want to call wait_on_page_locked()
         * against a page without get_page().
         * So, we use get_page_unless_zero(), here. Even failed, page fault
         * will occur again.
         */
	if (!get_page_unless_zero(page))
		goto out;
	pte_unmap_unlock(ptep, ptl);
	wait_on_page_locked(page);
	put_page(page);
	return;
out:
	pte_unmap_unlock(ptep, ptl);
}

Contributors
Person Tokens Prop Commits CommitProp
Christoph Lameter 98 85.96% 1 33.33%
Nicholas Piggin 9 7.89% 1 33.33%
Naoya Horiguchi 7 6.14% 1 33.33%
Total 114 100.00% 3 100.00%



void migration_entry_wait(struct mm_struct *mm, pmd_t *pmd,
				unsigned long address)
{
	spinlock_t *ptl = pte_lockptr(mm, pmd);
	pte_t *ptep = pte_offset_map(pmd, address);
	__migration_entry_wait(mm, ptep, ptl);
}

Contributors
Person Tokens Prop Commits CommitProp
Naoya Horiguchi 49 100.00% 1 100.00%
Total 49 100.00% 1 100.00%



void migration_entry_wait_huge(struct vm_area_struct *vma,
		struct mm_struct *mm, pte_t *pte)
{
	spinlock_t *ptl = huge_pte_lockptr(hstate_vma(vma), mm, pte);
	__migration_entry_wait(mm, pte, ptl);
}

Contributors
Person Tokens Prop Commits CommitProp
Naoya Horiguchi 29 65.91% 1 50.00%
Kirill A. Shutemov 15 34.09% 1 50.00%
Total 44 100.00% 2 100.00%

#ifdef CONFIG_BLOCK
/* Returns true if all buffers are successfully locked */


static bool buffer_migrate_lock_buffers(struct buffer_head *head,
							enum migrate_mode mode)
{
	struct buffer_head *bh = head;

	/* Simple case, sync compaction */
	if (mode != MIGRATE_ASYNC) {
		do {
			get_bh(bh);
			lock_buffer(bh);
			bh = bh->b_this_page;

		} while (bh != head);

		return true;
	}

	/* async case, we cannot block on lock_buffer so use trylock_buffer */
	do {
		get_bh(bh);
		if (!trylock_buffer(bh)) {
			/*
                         * We failed to lock the buffer and cannot stall in
                         * async migration. Release the taken locks
                         */
			struct buffer_head *failed_bh = bh;
			put_bh(failed_bh);
			bh = head;
			while (bh != failed_bh) {
				unlock_buffer(bh);
				put_bh(bh);
				bh = bh->b_this_page;
			}
			return false;
		}

		bh = bh->b_this_page;
	} while (bh != head);
	return true;
}
Contributors
Person Tokens Prop Commits CommitProp
Mel Gorman 139 100.00% 2 100.00%
Total 139 100.00% 2 100.00%

#else


static inline bool buffer_migrate_lock_buffers(struct buffer_head *head,
							enum migrate_mode mode)
{
	return true;
}
Contributors
Person Tokens Prop Commits CommitProp
Mel Gorman 19 100.00% 2 100.00%
Total 19 100.00% 2 100.00%

#endif /* CONFIG_BLOCK */

/*
 * Replace the page in the mapping.
 *
 * The number of remaining references must be:
 * 1 for anonymous pages without a mapping
 * 2 for pages with a mapping
 * 3 for pages with a mapping and PagePrivate/PagePrivate2 set.
 */


int migrate_page_move_mapping(struct address_space *mapping,
		struct page *newpage, struct page *page,
		struct buffer_head *head, enum migrate_mode mode,
		int extra_count)
{
	struct zone *oldzone, *newzone;
	int dirty;
	int expected_count = 1 + extra_count;
	void **pslot;

	if (!mapping) {
		/* Anonymous page without mapping */
		if (page_count(page) != expected_count)
			return -EAGAIN;

		/* No turning back from here */
		newpage->index = page->index;
		newpage->mapping = page->mapping;
		if (PageSwapBacked(page))
			__SetPageSwapBacked(newpage);

		return MIGRATEPAGE_SUCCESS;
	}

	oldzone = page_zone(page);
	newzone = page_zone(newpage);

	spin_lock_irq(&mapping->tree_lock);

	pslot = radix_tree_lookup_slot(&mapping->page_tree,
 					page_index(page));

	expected_count += 1 + page_has_private(page);
	if (page_count(page) != expected_count ||
		radix_tree_deref_slot_protected(pslot, &mapping->tree_lock) != page) {
		spin_unlock_irq(&mapping->tree_lock);
		return -EAGAIN;
	}

	if (!page_ref_freeze(page, expected_count)) {
		spin_unlock_irq(&mapping->tree_lock);
		return -EAGAIN;
	}

	/*
         * In the async migration case of moving a page with buffers, lock the
         * buffers using trylock before the mapping is moved. If the mapping
         * was moved, we later failed to lock the buffers and could not move
         * the mapping back due to an elevated page count, we would have to
         * block waiting on other references to be dropped.
         */
	if (mode == MIGRATE_ASYNC && head &&
			!buffer_migrate_lock_buffers(head, mode)) {
		page_ref_unfreeze(page, expected_count);
		spin_unlock_irq(&mapping->tree_lock);
		return -EAGAIN;
	}

	/*
         * Now we know that no one else is looking at the page:
         * no turning back from here.
         */
	newpage->index = page->index;
	newpage->mapping = page->mapping;
	get_page(newpage);	/* add cache reference */
	if (PageSwapBacked(page)) {
		__SetPageSwapBacked(newpage);
		if (PageSwapCache(page)) {
			SetPageSwapCache(newpage);
			set_page_private(newpage, page_private(page));
		}
	} else {
		VM_BUG_ON_PAGE(PageSwapCache(page), page);
	}

	/* Move dirty while page refs frozen and newpage not yet exposed */
	dirty = PageDirty(page);
	if (dirty) {
		ClearPageDirty(page);
		SetPageDirty(newpage);
	}

	radix_tree_replace_slot(&mapping->page_tree, pslot, newpage);

	/*
         * Drop cache reference from old page by unfreezing
         * to one less reference.
         * We know this isn't the last reference.
         */
	page_ref_unfreeze(page, expected_count - 1);

	spin_unlock(&mapping->tree_lock);
	/* Leave irq disabled to prevent preemption while updating stats */

	/*
         * If moved to a different zone then also account
         * the page for that zone. Other VM counters will be
         * taken care of when we establish references to the
         * new page and drop references to the old page.
         *
         * Note that anonymous pages are accounted for
         * via NR_FILE_PAGES and NR_ANON_MAPPED if they
         * are mapped to swap space.
         */
	if (newzone != oldzone) {
		__dec_node_state(oldzone->zone_pgdat, NR_FILE_PAGES);
		__inc_node_state(newzone->zone_pgdat, NR_FILE_PAGES);
		if (PageSwapBacked(page) && !PageSwapCache(page)) {
			__dec_node_state(oldzone->zone_pgdat, NR_SHMEM);
			__inc_node_state(newzone->zone_pgdat, NR_SHMEM);
		}
		if (dirty && mapping_cap_account_dirty(mapping)) {
			__dec_node_state(oldzone->zone_pgdat, NR_FILE_DIRTY);
			__dec_zone_state(oldzone, NR_ZONE_WRITE_PENDING);
			__inc_node_state(newzone->zone_pgdat, NR_FILE_DIRTY);
			__inc_zone_state(newzone, NR_ZONE_WRITE_PENDING);
		}
	}
	local_irq_enable();

	return MIGRATEPAGE_SUCCESS;
}
Contributors
Person Tokens Prop Commits CommitProp
Hugh Dickins 144 29.45% 3 10.34%
Christoph Lameter 131 26.79% 7 24.14%
Mel Gorman 94 19.22% 6 20.69%
Nicholas Piggin 74 15.13% 4 13.79%
Motohiro Kosaki 18 3.68% 1 3.45%
Benjamin LaHaise 9 1.84% 1 3.45%
Johannes Weiner 5 1.02% 1 3.45%
Andrea Arcangeli 4 0.82% 1 3.45%
JoonSoo Kim 3 0.61% 1 3.45%
Jacobo Giralt 3 0.61% 1 3.45%
Rafael Aquini 2 0.41% 1 3.45%
Peter Zijlstra 1 0.20% 1 3.45%
David Howells 1 0.20% 1 3.45%
Total 489 100.00% 29 100.00%


EXPORT_SYMBOL(migrate_page_move_mapping);

/*
 * The expected number of remaining references is the same as that
 * of migrate_page_move_mapping().
 */


int migrate_huge_page_move_mapping(struct address_space *mapping,
				   struct page *newpage, struct page *page)
{
	int expected_count;
	void **pslot;

	spin_lock_irq(&mapping->tree_lock);

	pslot = radix_tree_lookup_slot(&mapping->page_tree,
					page_index(page));

	expected_count = 2 + page_has_private(page);
	if (page_count(page) != expected_count ||
		radix_tree_deref_slot_protected(pslot, &mapping->tree_lock) != page) {
		spin_unlock_irq(&mapping->tree_lock);
		return -EAGAIN;
	}

	if (!page_ref_freeze(page, expected_count)) {
		spin_unlock_irq(&mapping->tree_lock);
		return -EAGAIN;
	}

	newpage->index = page->index;
	newpage->mapping = page->mapping;

	get_page(newpage);

	radix_tree_replace_slot(&mapping->page_tree, pslot, newpage);

	page_ref_unfreeze(page, expected_count - 1);

	spin_unlock_irq(&mapping->tree_lock);

	return MIGRATEPAGE_SUCCESS;
}

Contributors
Person Tokens Prop Commits CommitProp
Naoya Horiguchi 84 48.84% 1 9.09%
Christoph Lameter 41 23.84% 1 9.09%
Hugh Dickins 17 9.88% 2 18.18%
Lee Schermerhorn 10 5.81% 1 9.09%
Mel Gorman 6 3.49% 1 9.09%
Johannes Weiner 5 2.91% 1 9.09%
Nicholas Piggin 4 2.33% 1 9.09%
Jacobo Giralt 2 1.16% 1 9.09%
JoonSoo Kim 2 1.16% 1 9.09%
Rafael Aquini 1 0.58% 1 9.09%
Total 172 100.00% 11 100.00%

/*
 * Gigantic pages are so large that we do not guarantee that page++ pointer
 * arithmetic will work across the entire page.  We need something more
 * specialized.
 */


static void __copy_gigantic_page(struct page *dst, struct page *src,
				int nr_pages)
{
	int i;
	struct page *dst_base = dst;
	struct page *src_base = src;

	for (i = 0; i < nr_pages; ) {
		cond_resched();
		copy_highpage(dst, src);

		i++;
		dst = mem_map_next(dst, dst_base, i);
		src = mem_map_next(src, src_base, i);
	}
}

Contributors
Person Tokens Prop Commits CommitProp
Dave Hansen 84 100.00% 1 100.00%
Total 84 100.00% 1 100.00%



static void copy_huge_page(struct page *dst, struct page *src)
{
	int i;
	int nr_pages;

	if (PageHuge(src)) {
		/* hugetlbfs page */
		struct hstate *h = page_hstate(src);
		nr_pages = pages_per_huge_page(h);

		if (unlikely(nr_pages > MAX_ORDER_NR_PAGES)) {
			__copy_gigantic_page(dst, src, nr_pages);
			return;
		}
	} else {
		/* thp page */
		BUG_ON(!PageTransHuge(src));
		nr_pages = hpage_nr_pages(src);
	}

	for (i = 0; i < nr_pages; i++) {
		cond_resched();
		copy_highpage(dst + i, src + i);
	}
}

Contributors
Person Tokens Prop Commits CommitProp
Dave Hansen 119 100.00% 1 100.00%
Total 119 100.00% 1 100.00%

/*
 * Copy the page to its new location
 */


void migrate_page_copy(struct page *newpage, struct page *page)
{
	int cpupid;

	if (PageHuge(page) || PageTransHuge(page))
		copy_huge_page(newpage, page);
	else
		copy_highpage(newpage, page);

	if (PageError(page))
		SetPageError(newpage);
	if (PageReferenced(page))
		SetPageReferenced(newpage);
	if (PageUptodate(page))
		SetPageUptodate(newpage);
	if (TestClearPageActive(page)) {
		VM_BUG_ON_PAGE(PageUnevictable(page), page);
		SetPageActive(newpage);
	} else if (TestClearPageUnevictable(page))
		SetPageUnevictable(newpage);
	if (PageChecked(page))
		SetPageChecked(newpage);
	if (PageMappedToDisk(page))
		SetPageMappedToDisk(newpage);

	/* Move dirty on pages not done by migrate_page_move_mapping() */
	if (PageDirty(page))
		SetPageDirty(newpage);

	if (page_is_young(page))
		set_page_young(newpage);
	if (page_is_idle(page))
		set_page_idle(newpage);

	/*
         * Copy NUMA information to the new page, to prevent over-eager
         * future migrations of this same page.
         */
	cpupid = page_cpupid_xchg_last(page, -1);
	page_cpupid_xchg_last(newpage, cpupid);

	ksm_migrate_page(newpage, page);
	/*
         * Please do not reorder this without considering how mm/ksm.c's
         * get_ksm_page() depends upon ksm_migrate_page() and PageSwapCache().
         */
	if (PageSwapCache(page))
		ClearPageSwapCache(page);
	ClearPagePrivate(page);
	set_page_private(page, 0);

	/*
         * If any waiters have accumulated on the new page then
         * wake them up.
         */
	if (PageWriteback(newpage))
		end_page_writeback(newpage);

	copy_page_owner(page, newpage);

	mem_cgroup_migrate(page, newpage);
}
Contributors
Person Tokens Prop Commits CommitProp
Naoya Horiguchi 148 57.81% 2 15.38%
Christoph Lameter 31 12.11% 1 7.69%
Vladimir Davydov 24 9.38% 1 7.69%
Rik Van Riel 21 8.20% 1 7.69%
Hugh Dickins 10 3.91% 4 30.77%
Vlastimil Babka 7 2.73% 1 7.69%
Johannes Weiner 7 2.73% 1 7.69%
Mel Gorman 5 1.95% 1 7.69%
Sasha Levin 3 1.17% 1 7.69%
Total 256 100.00% 13 100.00%


EXPORT_SYMBOL(migrate_page_copy);

/************************************************************
 *                    Migration functions
 ***********************************************************/

/*
 * Common logic to directly migrate a single LRU page suitable for
 * pages that do not use PagePrivate/PagePrivate2.
 *
 * Pages are locked upon entry and exit.
 */


int migrate_page(struct address_space *mapping,
		struct page *newpage, struct page *page,
		enum migrate_mode mode)
{
	int rc;

	BUG_ON(PageWriteback(page));	/* Writeback must be complete */

	rc = migrate_page_move_mapping(mapping, newpage, page, NULL, mode, 0);

	if (rc != MIGRATEPAGE_SUCCESS)
		return rc;

	migrate_page_copy(newpage, page);
	return MIGRATEPAGE_SUCCESS;
}
Contributors
Person Tokens Prop Commits CommitProp
Christoph Lameter 59 81.94% 3 42.86%
Mel Gorman 8 11.11% 2 28.57%
Rafael Aquini 3 4.17% 1 14.29%
Benjamin LaHaise 2 2.78% 1 14.29%
Total 72 100.00% 7 100.00%


EXPORT_SYMBOL(migrate_page);

#ifdef CONFIG_BLOCK
/*
 * Migration function for pages with buffers. This function can only be used
 * if the underlying filesystem guarantees that no other references to "page"
 * exist.
 */


int buffer_migrate_page(struct address_space *mapping,
		struct page *newpage, struct page *page, enum migrate_mode mode)
{
	struct buffer_head *bh, *head;
	int rc;

	if (!page_has_buffers(page))
		return migrate_page(mapping, newpage, page, mode);

	head = page_buffers(page);

	rc = migrate_page_move_mapping(mapping, newpage, page, head, mode, 0);

	if (rc != MIGRATEPAGE_SUCCESS)
		return rc;

	/*
         * In the async case, migrate_page_move_mapping locked the buffers
         * with an IRQ-safe spinlock held. In the sync case, the buffers
         * need to be locked now
         */
	if (mode != MIGRATE_ASYNC)
		BUG_ON(!buffer_migrate_lock_buffers(head, mode));

	ClearPagePrivate(page);
	set_page_private(newpage, page_private(page));
	set_page_private(page, 0);
	put_page(page);
	get_page(newpage);

	bh = head;
	do {
		set_bh_page(bh, newpage, bh_offset(bh));
		bh = bh->b_this_page;

	} while (bh != head);

	SetPagePrivate(newpage);

	migrate_page_copy(newpage, page);

	bh = head;
	do {
		unlock_buffer(bh);
 		put_bh(bh);
		bh = bh->b_this_page;

	} while (bh != head);

	return MIGRATEPAGE_SUCCESS;
}
Contributors
Person Tokens Prop Commits CommitProp
Christoph Lameter 186 86.51% 4 50.00%
Mel Gorman 24 11.16% 2 25.00%
Rafael Aquini 3 1.40% 1 12.50%
Benjamin LaHaise 2 0.93% 1 12.50%
Total 215 100.00% 8 100.00%


EXPORT_SYMBOL(buffer_migrate_page);
#endif

/*
 * Writeback a page to clean the dirty state
 */


static int writeout(struct address_space *mapping, struct page *page)
{
	struct writeback_control wbc = {
		.sync_mode = WB_SYNC_NONE,
		.nr_to_write = 1,
		.range_start = 0,
		.range_end = LLONG_MAX,
		.for_reclaim = 1
	};
	int rc;

	if (!mapping->a_ops->writepage)
		/* No write method for the address space */
		return -EINVAL;

	if (!clear_page_dirty_for_io(page))
		/* Someone else already triggered a write */
		return -EAGAIN;

	/*
         * A dirty page may imply that the underlying filesystem has
         * the page on some queue. So the page must be clean for
         * migration. Writeout may mean we loose the lock and the
         * page state is no longer what we checked for earlier.
         * At this point we know that the migration attempt cannot
         * be successful.
         */
	remove_migration_ptes(page, page, false);

	rc = mapping->a_ops->writepage(page, &wbc);

	if (rc != AOP_WRITEPAGE_ACTIVATE)
		/* unlocked. Relock */
		lock_page(page);

	return (rc < 0) ? -EIO : -EAGAIN;
}

Contributors
Person Tokens Prop Commits CommitProp
Christoph Lameter 115 91.27% 2 50.00%
Hugh Dickins 9 7.14% 1 25.00%
Kirill A. Shutemov 2 1.59% 1 25.00%
Total 126 100.00% 4 100.00%

/*
 * Default handling if a filesystem does not provide a migration function.
 */


static int fallback_migrate_page(struct address_space *mapping,
	struct page *newpage, struct page *page, enum migrate_mode mode)
{
	if (PageDirty(page)) {
		/* Only writeback pages in full synchronous migration */
		if (mode != MIGRATE_SYNC)
			return -EBUSY;
		return writeout(mapping, page);
	}

	/*
         * Buffers may be managed in a filesystem specific way.
         * We must have no buffers or drop them.
         */
	if (page_has_private(page) &&
	    !try_to_release_page(page, GFP_KERNEL))
		return -EAGAIN;

	return migrate_page(mapping, newpage, page, mode);
}

Contributors
Person Tokens Prop Commits CommitProp
Christoph Lameter 65 76.47% 2 40.00%
Mel Gorman 19 22.35% 2 40.00%
David Howells 1 1.18% 1 20.00%
Total 85 100.00% 5 100.00%

/*
 * Move a page to a newly allocated page
 * The page is locked and all ptes have been successfully removed.
 *
 * The new page will have replaced the old page if this function
 * is successful.
 *
 * Return value:
 *   < 0 - error code
 *  MIGRATEPAGE_SUCCESS - success
 */


static int move_to_new_page(struct page *newpage, struct page *page,
				enum migrate_mode mode)
{
	struct address_space *mapping;
	int rc = -EAGAIN;
	bool is_lru = !__PageMovable(page);

	VM_BUG_ON_PAGE(!PageLocked(page), page);
	VM_BUG_ON_PAGE(!PageLocked(newpage), newpage);

	mapping = page_mapping(page);

	if (likely(is_lru)) {
		if (!mapping)
			rc = migrate_page(mapping, newpage, page, mode);
		else if (mapping->a_ops->migratepage)
			/*
                         * Most pages have a mapping and most filesystems
                         * provide a migratepage callback. Anonymous pages
                         * are part of swap space which also has its own
                         * migratepage callback. This is the most common path
                         * for page migration.
                         */
			rc = mapping->a_ops->migratepage(mapping, newpage,
							page, mode);
		else
			rc = fallback_migrate_page(mapping, newpage,
							page, mode);
	} else {
		/*
                 * In case of non-lru page, it could be released after
                 * isolation step. In that case, we shouldn't try migration.
                 */
		VM_BUG_ON_PAGE(!PageIsolated(page), page);
		if (!PageMovable(page)) {
			rc = MIGRATEPAGE_SUCCESS;
			__ClearPageIsolated(page);
			goto out;
		}

		rc = mapping->a_ops->migratepage(mapping, newpage,
						page, mode);
		WARN_ON_ONCE(rc == MIGRATEPAGE_SUCCESS &&
			!PageIsolated(page));
	}

	/*
         * When successful, old pagecache page->mapping must be cleared before
         * page is freed; but stats require that PageAnon be left as PageAnon.
         */
	if (rc == MIGRATEPAGE_SUCCESS) {
		if (__PageMovable(page)) {
			VM_BUG_ON_PAGE(!PageIsolated(page), page);

			/*
                         * We clear PG_movable under page_lock so any compactor
                         * cannot try to migrate this page.
                         */
			__ClearPageIsolated(page);
		}

		/*
                 * Anonymous and movable page->mapping will be cleard by
                 * free_pages_prepare so don't reset it here for keeping
                 * the type to work PageAnon, for example.
                 */
		if (!PageMappingFlags(page))
			page->mapping = NULL;
	}
out:
	return rc;
}

Contributors
Person Tokens Prop Commits CommitProp
MinChan Kim 119 45.95% 1 6.67%
Christoph Lameter 92 35.52% 6 40.00%
Hugh Dickins 27 10.42% 2 13.33%
Mel Gorman 18 6.95% 3 20.00%
Rafael Aquini 1 0.39% 1 6.67%
Andrea Arcangeli 1 0.39% 1 6.67%
Nicholas Piggin 1 0.39% 1 6.67%
Total 259 100.00% 15 100.00%



static int __unmap_and_move(struct page *page, struct page *newpage,
				int force, enum migrate_mode mode)
{
	int rc = -EAGAIN;
	int page_was_mapped = 0;
	struct anon_vma *anon_vma = NULL;
	bool is_lru = !__PageMovable(page);

	if (!trylock_page(page)) {
		if (!force || mode == MIGRATE_ASYNC)
			goto out;

		/*
                 * It's not safe for direct compaction to call lock_page.
                 * For example, during page readahead pages are added locked
                 * to the LRU. Later, when the IO completes the pages are
                 * marked uptodate and unlocked. However, the queueing
                 * could be merging multiple pages for one bio (e.g.
                 * mpage_readpages). If an allocation happens for the
                 * second or third page, the process can end up locking
                 * the same page twice and deadlocking. Rather than
                 * trying to be clever about what pages can be locked,
                 * avoid the use of lock_page for direct compaction
                 * altogether.
                 */
		if (current->flags & PF_MEMALLOC)
			goto out;

		lock_page(page);
	}

	if (PageWriteback(page)) {
		/*
                 * Only in the case of a full synchronous migration is it
                 * necessary to wait for PageWriteback. In the async case,
                 * the retry loop is too short and in the sync-light case,
                 * the overhead of stalling is too much
                 */
		if (mode != MIGRATE_SYNC) {
			rc = -EBUSY;
			goto out_unlock;
		}
		if (!force)
			goto out_unlock;
		wait_on_page_writeback(page);
	}

	/*
         * By try_to_unmap(), page->mapcount goes down to 0 here. In this case,
         * we cannot notice that anon_vma is freed while we migrates a page.
         * This get_anon_vma() delays freeing anon_vma pointer until the end
         * of migration. File cache pages are no problem because of page_lock()
         * File Caches may use write_page() or lock_page() in migration, then,
         * just care Anon page here.
         *
         * Only page_get_anon_vma() understands the subtleties of
         * getting a hold on an anon_vma from outside one of its mms.
         * But if we cannot get anon_vma, then we won't need it anyway,
         * because that implies that the anon page is no longer mapped
         * (and cannot be remapped so long as we hold the page lock).
         */
	if (PageAnon(page) && !PageKsm(page))
		anon_vma = page_get_anon_vma(page);

	/*
         * Block others from accessing the new page when we get around to
         * establishing additional references. We are usually the only one
         * holding a reference to newpage at this point. We used to have a BUG
         * here if trylock_page(newpage) fails, but would like to allow for
         * cases where there might be a race with the previous use of newpage.
         * This is much like races on refcount of oldpage: just don't BUG().
         */
	if (unlikely(!trylock_page(newpage)))
		goto out_unlock;

	if (unlikely(!is_lru)) {
		rc = move_to_new_page(newpage, page, mode);
		goto out_unlock_both;
	}

	/*
         * Corner case handling:
         * 1. When a new swap-cache page is read into, it is added to the LRU
         * and treated as swapcache but it has no rmap yet.
         * Calling try_to_unmap() against a page->mapping==NULL page will
         * trigger a BUG.  So handle it here.
         * 2. An orphaned page (see truncate_complete_page) might have
         * fs-private metadata. The page can be picked up due to memory
         * offlining.  Everywhere else except page reclaim, the page is
         * invisible to the vm, so the page can not be migrated.  So try to
         * free the metadata, so the page can be freed.
         */
	if (!page->mapping) {
		VM_BUG_ON_PAGE(PageAnon(page), page);
		if (page_has_private(page)) {
			try_to_free_buffers(page);
			goto out_unlock_both;
		}
	} else if (page_mapped(page)) {
		/* Establish migration ptes */
		VM_BUG_ON_PAGE(PageAnon(page) && !PageKsm(page) && !anon_vma,
				page);
		try_to_unmap(page,
			TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS);
		page_was_mapped = 1;
	}

	if (!page_mapped(page))
		rc = move_to_new_page(newpage, page, mode);

	if (page_was_mapped)
		remove_migration_ptes(page,
			rc == MIGRATEPAGE_SUCCESS ? newpage : page, false);

out_unlock_both:
	unlock_page(newpage);
out_unlock:
	/* Drop an anon_vma reference if we took one */
	if (anon_vma)
		put_anon_vma(anon_vma);
	unlock_page(page);
out:
	/*
         * If migration is successful, decrease refcount of the newpage
         * which will not free the page because new page owner increased
         * refcounter. As well, if it is LRU page, add the page to LRU
         * list in here.
         */
	if (rc == MIGRATEPAGE_SUCCESS) {
		if (unlikely(__PageMovable(newpage)))
			put_page(newpage);
		else
			putback_lru_page(newpage);
	}

	return rc;
}

Contributors
Person Tokens Prop Commits CommitProp
Christoph Lameter 94 25.61% 6 16.22%
Hugh Dickins 83 22.62% 7 18.92%
MinChan Kim 75 20.44% 3 8.11%
Mel Gorman 42 11.44% 5 13.51%
Kamezawa Hiroyuki 19 5.18% 3 8.11%
David Shaohua Li 18 4.90% 2 5.41%
Andrea Arcangeli 15 4.09% 1 2.70%
Andi Kleen 5 1.36% 1 2.70%
Rafael Aquini 4 1.09% 1 2.70%
Sasha Levin 3 0.82% 1 2.70%
Kirill A. Shutemov 2 0.54% 1 2.70%
Johannes Weiner 2 0.54% 1 2.70%
Peter Zijlstra 2 0.54% 2 5.41%
Jianguo Wu 1 0.27% 1 2.70%
David Howells 1 0.27% 1 2.70%
Nicholas Piggin 1 0.27% 1 2.70%
Total 367 100.00% 37 100.00%

/*
 * gcc 4.7 and 4.8 on arm get an ICEs when inlining unmap_and_move().  Work
 * around it.
 */
#if (GCC_VERSION >= 40700 && GCC_VERSION < 40900) && defined(CONFIG_ARM)

#define ICE_noinline noinline
#else

#define ICE_noinline
#endif

/*
 * Obtain the lock on page, remove all ptes and migrate the page
 * to the newly allocated page in newpage.
 */


static ICE_noinline int unmap_and_move(new_page_t get_new_page,
				   free_page_t put_new_page,
				   unsigned long private, struct page *page,
				   int force, enum migrate_mode mode,
				   enum migrate_reason reason)
{
	int rc = MIGRATEPAGE_SUCCESS;
	int *result = NULL;
	struct page *newpage;

	newpage = get_new_page(page, private, &result);
	if (!newpage)
		return -ENOMEM;

	if (page_count(page) == 1) {
		/* page was freed from under us. So we are done. */
		ClearPageActive(page);
		ClearPageUnevictable(page);
		if (unlikely(__PageMovable(page))) {
			lock_page(page);
			if (!PageMovable(page))
				__ClearPageIsolated(page);
			unlock_page(page);
		}
		if (put_new_page)
			put_new_page(newpage, private);
		else
			put_page(newpage);
		goto out;
	}

	if (unlikely(PageTransHuge(page))) {
		lock_page(page);
		rc = split_huge_page(page);
		unlock_page(page);
		if (rc)
			goto out;
	}

	rc = __unmap_and_move(page, newpage, force, mode);
	if (rc == MIGRATEPAGE_SUCCESS)
		set_page_owner_migrate_reason(newpage, reason);

out:
	if (rc != -EAGAIN) {
		/*
                 * A page that has been migrated has all references
                 * removed and will be freed. A page that has not been
                 * migrated will have kepts its references and be
                 * restored.
                 */
		list_del(&page->lru);

		/*
                 * Compaction can migrate also non-LRU pages which are
                 * not accounted to NR_ISOLATED_*. They can be recognized
                 * as __PageMovable
                 */
		if (likely(!__PageMovable(page)))
			dec_node_page_state(page, NR_ISOLATED_ANON +
					page_is_file_cache(page));
	}

	/*
         * If migration is successful, releases reference grabbed during
         * isolation. Otherwise, restore the page to right list unless
         * we want to retry.
         */
	if (rc == MIGRATEPAGE_SUCCESS) {
		put_page(page);
		if (reason == MR_MEMORY_FAILURE) {
			/*
                         * Set PG_HWPoison on just freed page
                         * intentionally. Although it's rather weird,
                         * it's how HWPoison flag works at the moment.
                         */
			if (!test_set_page_hwpoison(page))
				num_poisoned_pages_inc();
		}
	} else {
		if (rc != -EAGAIN) {
			if (likely(!__PageMovable(page))) {
				putback_lru_page(page);
				goto put_new;
			}

			lock_page(page);
			if (PageMovable(page))
				putback_movable_page(page);
			else
				__ClearPageIsolated(page);
			unlock_page(page);
			put_page(page);
		}
put_new:
		if (put_new_page)
			put_new_page(newpage, private);
		else
			put_page(newpage);
	}

	if (result) {
		if (rc)
			*result = rc;
		else
			*result = page_to_nid(newpage);
	}
	return rc;
}

Contributors
Person Tokens Prop Commits CommitProp
MinChan Kim 240 60.15% 4 16.67%
Christoph Lameter 48 12.03% 5 20.83%
Kirill A. Shutemov 16 4.01% 1 4.17%
David Rientjes 14 3.51% 1 4.17%
Naoya Horiguchi 13 3.26% 2 8.33%
Wanpeng Li 13 3.26% 1 4.17%
Lin Ming 12 3.01% 1 4.17%
Motohiro Kosaki 11 2.76% 1 4.17%
Hugh Dickins 11 2.76% 1 4.17%
Vlastimil Babka 7 1.75% 1 4.17%
Konstantin Khlebnikov 6 1.50% 1 4.17%
Mel Gorman 5 1.25% 2 8.33%
Lee Schermerhorn 1 0.25% 1 4.17%
Geert Uytterhoeven 1 0.25% 1 4.17%
Andrea Arcangeli 1 0.25% 1 4.17%
Total 399 100.00% 24 100.00%

/*
 * Counterpart of unmap_and_move_page() for hugepage migration.
 *
 * This function doesn't wait the completion of hugepage I/O
 * because there is no race between I/O and migration for hugepage.
 * Note that currently hugepage I/O occurs only in direct I/O
 * where no lock is held and PG_writeback is irrelevant,
 * and writeback status of all subpages are counted in the reference
 * count of the head page (i.e. if all subpages of a 2MB hugepage are
 * under direct I/O, the reference of the head page is 512 and a bit more.)
 * This means that when we try to migrate hugepage whose subpages are
 * doing direct I/O, some references remain after try_to_unmap() and
 * hugepage migration fails without data corruption.
 *
 * There is also no race when direct I/O is issued on the page under migration,
 * because then pte is replaced with migration swap entry and direct I/O code
 * will wait in the page fault for migration to complete.
 */


static int unmap_and_move_huge_page(new_page_t get_new_page,
				free_page_t put_new_page, unsigned long private,
				struct page *hpage, int force,
				enum migrate_mode mode, int reason)
{
	int rc = -EAGAIN;
	int *result = NULL;
	int page_was_mapped = 0;
	struct page *new_hpage;
	struct anon_vma *anon_vma = NULL;

	/*
         * Movability of hugepages depends on architectures and hugepage size.
         * This check is necessary because some callers of hugepage migration
         * like soft offline and memory hotremove don't walk through page
         * tables or check whether the hugepage is pmd-based or not before
         * kicking migration.
         */
	if (!hugepage_migration_supported(page_hstate(hpage))) {
		putback_active_hugepage(hpage);
		return -ENOSYS;
	}

	new_hpage = get_new_page(hpage, private, &result);
	if (!new_hpage)
		return -ENOMEM;

	if (!trylock_page(hpage)) {
		if (!force || mode != MIGRATE_SYNC)
			goto out;
		lock_page(hpage);
	}

	if (PageAnon(hpage))
		anon_vma = page_get_anon_vma(hpage);

	if (unlikely(!trylock_page(new_hpage)))
		goto put_anon;

	if (page_mapped(hpage)) {
		try_to_unmap(hpage,
			TTU_MIGRATION|TTU_IGNORE_MLOCK|TTU_IGNORE_ACCESS);
		page_was_mapped = 1;
	}

	if (!page_mapped(hpage))
		rc = move_to_new_page(new_hpage, hpage, mode);

	if (page_was_mapped)
		remove_migration_ptes(hpage,
			rc == MIGRATEPAGE_SUCCESS ? new_hpage : hpage, false);

	unlock_page(new_hpage);

put_anon:
	if (anon_vma)
		put_anon_vma(anon_vma);

	if (rc == MIGRATEPAGE_SUCCESS) {
		hugetlb_cgroup_migrate(hpage, new_hpage);
		put_new_page = NULL;
		set_page_owner_migrate_reason(new_hpage, reason);
	}

	unlock_page(hpage);
out:
	if (rc != -EAGAIN)
		putback_active_hugepage(hpage);

	/*
         * If migration was not successful and there's a freeing callback, use
         * it.  Otherwise, put_page() will drop the reference grabbed during
         * isolation.
         */
	if (put_new_page)
		put_new_page(new_hpage, private);
	else
		putback_active_hugepage(new_hpage);

	if (result) {
		if (rc)
			*result = rc;
		else
			*result = page_to_nid(new_hpage);
	}
	return rc;
}

Contributors
Person Tokens Prop Commits CommitProp
Naoya Horiguchi 173 52.91% 5 20.83%
Hugh Dickins 57 17.43% 6 25.00%
Christoph Lameter 25 7.65% 3 12.50%
JoonSoo Kim 19 5.81% 1 4.17%
David Rientjes 18 5.50% 1 4.17%
Aneesh Kumar K.V 11 3.36% 1 4.17%
Vlastimil Babka 10 3.06% 1 4.17%
Mel Gorman 8 2.45% 2 8.33%
Kirill A. Shutemov 2 0.61% 1 4.17%
Hillf Danton 2 0.61% 1 4.17%
Peter Zijlstra 2 0.61% 2 8.33%
Total 327 100.00% 24 100.00%

/*
 * migrate_pages - migrate the pages specified in a list, to the free pages
 *                 supplied as the target for the page migration
 *
 * @from:               The list of pages to be migrated.
 * @get_new_page:       The function used to allocate free pages to be used
 *                      as the target of the page migration.
 * @put_new_page:       The function used to free target pages if migration
 *                      fails, or NULL if no special handling is necessary.
 * @private:            Private data to be passed on to get_new_page()
 * @mode:               The migration mode that specifies the constraints for
 *                      page migration, if any.
 * @reason:             The reason for page migration.
 *
 * The function returns after 10 attempts or if no pages are movable any more
 * because the list has become empty or no retryable pages exist any more.
 * The caller should call putback_movable_pages() to return pages to the LRU
 * or free list only if ret != 0.
 *
 * Returns the number of pages that were not migrated, or an error code.
 */


int migrate_pages(struct list_head *from, new_page_t get_new_page,
		free_page_t put_new_page, unsigned long private,
		enum migrate_mode mode, int reason)
{
	int retry = 1;
	int nr_failed = 0;
	int nr_succeeded = 0;
	int pass = 0;
	struct page *page;
	struct page *page2;
	int swapwrite = current->flags & PF_SWAPWRITE;
	int rc;

	if (!swapwrite)
		current->flags |= PF_SWAPWRITE;

	for(pass = 0; pass < 10 && retry; pass++) {
		retry = 0;

		list_for_each_entry_safe(page, page2, from, lru) {
			cond_resched();

			if (PageHuge(page))
				rc = unmap_and_move_huge_page(get_new_page,
						put_new_page, private, page,
						pass > 2, mode, reason);
			else
				rc = unmap_and_move(get_new_page, put_new_page,
						private, page, pass > 2, mode,
						reason);

			switch(rc) {
			case -ENOMEM:
				nr_failed++;
				goto out;
			case -EAGAIN:
				retry++;
				break;
			case MIGRATEPAGE_SUCCESS:
				nr_succeeded++;
				break;
			default:
				/*
                                 * Permanent failure (-EBUSY, -ENOSYS, etc.):
                                 * unlike -EAGAIN case, the failed page is
                                 * removed from migration page list and not
                                 * retried in the next outer loop.
                                 */
				nr_failed++;
				break;
			}
		}
	}
	nr_failed += retry;
	rc = nr_failed;
out:
	if (nr_succeeded)
		count_vm_events(PGMIGRATE_SUCCESS, nr_succeeded);
	if (nr_failed)
		count_vm_events(PGMIGRATE_FAIL, nr_failed);
	trace_mm_migrate_pages(nr_succeeded, nr_failed, mode, reason);

	if (!swapwrite)
		current->flags &= ~PF_SWAPWRITE;

	return rc;
}

Contributors
Person Tokens Prop Commits CommitProp
Naoya Horiguchi 97 37.16% 4 25.00%
Christoph Lameter 97 37.16% 3 18.75%
Mel Gorman 48 18.39% 3 18.75%
David Rientjes 10 3.83% 2 12.50%
Vlastimil Babka 6 2.30% 2 12.50%
Rafael Aquini 2 0.77% 1 6.25%
Hugh Dickins 1 0.38% 1 6.25%
Total 261 100.00% 16 100.00%

#ifdef CONFIG_NUMA
/*
 * Move a list of individual pages
 */

struct page_to_node {
	
unsigned long addr;
	
struct page *page;
	
int node;
	
int status;
};



static struct page *new_page_node(struct page *p, unsigned long private,
		int **result)
{
	struct page_to_node *pm = (struct page_to_node *)private;

	while (pm->node != MAX_NUMNODES && pm->page != p)
		pm++;

	if (pm->node == MAX_NUMNODES)
		return NULL;

	*result = &pm->status;

	if (PageHuge(p))
		return alloc_huge_page_node(page_hstate(compound_head(p)),
					pm->node);
	else
		return __alloc_pages_node(pm->node,
				GFP_HIGHUSER_MOVABLE | __GFP_THISNODE, 0);
}

Contributors
Person Tokens Prop Commits CommitProp
Christoph Lameter 81 75.00% 2 33.33%
Naoya Horiguchi 24 22.22% 1 16.67%
Johannes Weiner 1 0.93% 1 16.67%
Vlastimil Babka 1 0.93% 1 16.67%
Mel Gorman 1 0.93% 1 16.67%
Total 108 100.00% 6 100.00%

/*
 * Move a set of pages as indicated in the pm array. The addr
 * field must be set to the virtual address of the page to be moved
 * and the node number must contain a valid target node.
 * The pm array ends with node = MAX_NUMNODES.
 */


static int do_move_page_to_node_array(struct mm_struct *mm,
				      struct page_to_node *pm,
				      int migrate_all)
{
	int err;
	struct page_to_node *pp;
	LIST_HEAD(pagelist);

	down_read(&mm->mmap_sem);

	/*
         * Build a list of pages to migrate
         */
	for (pp = pm; pp->node != MAX_NUMNODES; pp++) {
		struct vm_area_struct *vma;
		struct page *page;

		err = -EFAULT;
		vma = find_vma(mm, pp->addr);
		if (!vma || pp->addr < vma->vm_start || !vma_migratable(vma))
			goto set_status;

		/* FOLL_DUMP to ignore special (like zero) pages */
		page = follow_page(vma, pp->addr,
				FOLL_GET | FOLL_SPLIT | FOLL_DUMP);

		err = PTR_ERR(page);
		if (IS_ERR(page))
			goto set_status;

		err = -ENOENT;
		if (!page)
			goto set_status;

		pp->page = page;
		err = page_to_nid(page);

		if (err == pp->node)
			/*
                         * Node already in the right place
                         */
			goto put_and_set;

		err = -EACCES;
		if (page_mapcount(page) > 1 &&
				!migrate_all)
			goto put_and_set;

		if (PageHuge(page)) {
			if (PageHead(page))
				isolate_huge_page(page, &pagelist);
			goto put_and_set;
		}

		err = isolate_lru_page(page);
		if (!err) {
			list_add_tail(&page->lru, &pagelist);
			inc_node_page_state(page, NR_ISOLATED_ANON +
					    page_is_file_cache(page));
		}
put_and_set:
		/*
                 * Either remove the duplicate refcount from
                 * isolate_lru_page() or drop the page ref if it was
                 * not isolated.
                 */
		put_page(page);
set_status:
		pp->status = err;
	}

	err = 0;
	if (!list_empty(&pagelist)) {
		err = migrate_pages(&pagelist, new_page_node, NULL,
				(unsigned long)pm, MIGRATE_SYNC, MR_SYSCALL);
		if (err)
			putback_movable_pages(&pagelist);
	}

	up_read(&mm->mmap_sem);
	return err;
}

Contributors
Person Tokens Prop Commits CommitProp
Christoph Lameter 230 68.25% 2 11.11%
Naoya Horiguchi 28 8.31% 2 11.11%
Linus Torvalds 17 5.04% 1 5.56%
Motohiro Kosaki 13 3.86% 1 5.56%
Nicholas Piggin 13 3.86% 1 5.56%
MinChan Kim 11 3.26% 1 5.56%
Gleb Natapov 8 2.37% 1 5.56%
Brice Goglin 5 1.48% 2 11.11%
Mel Gorman 4 1.19% 3 16.67%
Kirill A. Shutemov 3 0.89% 1 5.56%
David Rientjes 2 0.59% 1 5.56%
Andrea Arcangeli 2 0.59% 1 5.56%
Hugh Dickins 1 0.30% 1 5.56%
Total 337 100.00% 18 100.00%

/*
 * Migrate an array of page address onto an array of nodes and fill
 * the corresponding array of status.
 */


static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
			 unsigned long nr_pages,
			 const void __user * __user *pages,
			 const int __user *nodes,
			 int __user *status, int flags)
{
	struct page_to_node *pm;
	unsigned long chunk_nr_pages;
	unsigned long chunk_start;
	int err;

	err = -ENOMEM;
	pm = (struct page_to_node *)__get_free_page(GFP_KERNEL);
	if (!pm)
		goto out;

	migrate_prep();

	/*
         * Store a chunk of page_to_node array in a page,
         * but keep the last one as a marker
         */
	chunk_nr_pages = (PAGE_SIZE / sizeof(struct page_to_node)) - 1;

	for (chunk_start = 0;
	     chunk_start < nr_pages;
	     chunk_start += chunk_nr_pages) {
		int j;

		if (chunk_start + chunk_nr_pages > nr_pages)
			chunk_nr_pages = nr_pages - chunk_start;

		/* fill the chunk pm with addrs and nodes from user-space */
		for (j = 0; j < chunk_nr_pages; j++) {
			const void __user *p;
			int node;

			err = -EFAULT;
			if (get_user(p, pages + j + chunk_start))
				goto out_pm;
			pm[j].addr = (unsigned long) p;

			if (get_user(node, nodes + j + chunk_start))
				goto out_pm;

			err = -ENODEV;
			if (node < 0 || node >= MAX_NUMNODES)
				goto out_pm;

			if (!node_state(node, N_MEMORY))
				goto out_pm;

			err = -EACCES;
			if (!node_isset(node, task_nodes))
				goto out_pm;

			pm[j].node = node;
		}

		/* End marker for this chunk */
		pm[chunk_nr_pages].node = MAX_NUMNODES;

		/* Migrate this chunk */
		err = do_move_page_to_node_array(mm, pm,
						 flags & MPOL_MF_MOVE_ALL);
		if (err < 0)
			goto out_pm;

		/* Return status information */
		for (j = 0; j < chunk_nr_pages; j++)
			if (put_user(pm[j].status, status + j + chunk_start)) {
				err = -EFAULT;
				goto out_pm;
			}
	}
	err = 0;

out_pm:
	free_page((unsigned long)pm);
out:
	return err;
}

Contributors
Person Tokens Prop Commits CommitProp
Brice Goglin 286 79.44% 4 44.44%
Christoph Lameter 50 13.89% 2 22.22%
Linus Torvalds 23 6.39% 2 22.22%
Lai Jiangshan 1 0.28% 1 11.11%
Total 360 100.00% 9 100.00%

/*
 * Determine the nodes of an array of pages and store it in an array of status.
 */


static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages,
				const void __user **pages, int *status)
{
	unsigned long i;

	down_read(&mm->mmap_sem);

	for (i = 0; i < nr_pages; i++) {
		unsigned long addr = (unsigned long)(*pages);
		struct vm_area_struct *vma;
		struct page *page;
		int err = -EFAULT;

		vma = find_vma(mm, addr);
		if (!vma || addr < vma->vm_start)
			goto set_status;

		/* FOLL_DUMP to ignore special (like zero) pages */
		page = follow_page(vma, addr, FOLL_DUMP);

		err = PTR_ERR(page);
		if (IS_ERR(page))
			goto set_status;

		err = page ? page_to_nid(page) : -ENOENT;
set_status:
		*status = err;

		pages++;
		status++;
	}

	up_read(&mm->mmap_sem);
}

Contributors
Person Tokens Prop Commits CommitProp
Brice Goglin 110 65.87% 2 33.33%
Christoph Lameter 42 25.15% 1 16.67%
Kirill A. Shutemov 6 3.59% 1 16.67%
Gleb Natapov 6 3.59% 1 16.67%
Motohiro Kosaki 3 1.80% 1 16.67%
Total 167 100.00% 6 100.00%

/*
 * Determine the nodes of a user array of pages and store it in
 * a user array of status.
 */


static int do_pages_stat(struct mm_struct *mm, unsigned long nr_pages,
			 const void __user * __user *pages,
			 int __user *status)
{

#define DO_PAGES_STAT_CHUNK_NR 16
	const void __user *chunk_pages[DO_PAGES_STAT_CHUNK_NR];
	int chunk_status[DO_PAGES_STAT_CHUNK_NR];

	while (nr_pages) {
		unsigned long chunk_nr;

		chunk_nr = nr_pages;
		if (chunk_nr > DO_PAGES_STAT_CHUNK_NR)
			chunk_nr = DO_PAGES_STAT_CHUNK_NR;

		if (copy_from_user(chunk_pages, pages, chunk_nr * sizeof(*chunk_pages)))
			break;

		do_pages_stat_array(mm, chunk_nr, chunk_pages, chunk_status);

		if (copy_to_user(status, chunk_status, chunk_nr * sizeof(*status)))
			break;

		pages += chunk_nr;
		status += chunk_nr;
		nr_pages -= chunk_nr;
	}
	return nr_pages ? -EFAULT : 0;
}

Contributors
Person Tokens Prop Commits CommitProp
Brice Goglin 105 76.09% 2 66.67%
H. Peter Anvin 33 23.91% 1 33.33%
Total 138 100.00% 3 100.00%

/*
 * Move a list of pages in the address space of the currently executing
 * process.
 */

SYSCALL_DEFINE6(move_pages, pid_t, pid, unsigned long, nr_pages,
		const void __user * __user *, pages,
		const int __user *, nodes,
		int __user *, status, int, flags)
{
	const struct cred *cred = current_cred(), *tcred;
	struct task_struct *task;
	struct mm_struct *mm;
	int err;
	nodemask_t task_nodes;

	/* Check flags */
	if (flags & ~(MPOL_MF_MOVE|MPOL_MF_MOVE_ALL))
		return -EINVAL;

	if ((flags & MPOL_MF_MOVE_ALL) && !capable(CAP_SYS_NICE))
		return -EPERM;

	/* Find the mm_struct */
	rcu_read_lock();
	task = pid ? find_task_by_vpid(pid) : current;
	if (!task) {
		rcu_read_unlock();
		return -ESRCH;
	}
	get_task_struct(task);

	/*
         * Check if this process has the right to modify the specified
         * process. The right exists if the process has administrative
         * capabilities, superuser privileges or the same
         * userid as the target process.
         */
	tcred = __task_cred(task);
	if (!uid_eq(cred->euid, tcred->suid) && !uid_eq(cred->euid, tcred->uid) &&
	    !uid_eq(cred->uid,  tcred->suid) && !uid_eq(cred->uid,  tcred->uid) &&
	    !capable(CAP_SYS_NICE)) {
		rcu_read_unlock();
		err = -EPERM;
		goto out;
	}
	rcu_read_unlock();

 	err = security_task_movememory(task);
 	if (err)
		goto out;

	task_nodes = cpuset_mems_allowed(task);
	mm = get_task_mm(task);
	put_task_struct(task);

	if (!mm)
		return -EINVAL;

	if (nodes)
		err = do_pages_move(mm, task_nodes, nr_pages, pages,
				    nodes, status, flags);
	else
		err = do_pages_stat(mm, nr_pages, pages, status);

	mmput(mm);
	return err;

out:
	put_task_struct(task);
	return err;
}

#ifdef CONFIG_NUMA_BALANCING
/*
 * Returns true if this is a safe migration target node for misplaced NUMA
 * pages. Currently it only checks the watermarks which crude
 */


static bool migrate_balanced_pgdat(struct pglist_data *pgdat,
				   unsigned long nr_migrate_pages)
{
	int z;

	if (!pgdat_reclaimable(pgdat))
		return false;

	for (z = pgdat->nr_zones - 1; z >= 0; z--) {
		struct zone *zone = pgdat->node_zones + z;

		if (!populated_zone(zone))
			continue;

		/* Avoid waking kswapd by allocating pages_to_migrate pages. */
		if (!zone_watermark_ok(zone, 0,
				       high_wmark_pages(zone) +
				       nr_migrate_pages,
				       0, 0))
			continue;
		return true;
	}
	return false;
}

Contributors
Person Tokens Prop Commits CommitProp
Peter Zijlstra 84 86.60% 1 33.33%
Mel Gorman 13 13.40% 2 66.67%
Total 97 100.00% 3 100.00%



static struct page *alloc_misplaced_dst_page(struct page *page,
					   unsigned long data,
					   int **result)
{
	int nid = (int) data;
	struct page *newpage;

	newpage = __alloc_pages_node(nid,
					 (GFP_HIGHUSER_MOVABLE |
					  __GFP_THISNODE | __GFP_NOMEMALLOC |
					  __GFP_NORETRY | __GFP_NOWARN) &
					 ~__GFP_RECLAIM, 0);

	return newpage;
}

Contributors
Person Tokens Prop Commits CommitProp
Peter Zijlstra 59 95.16% 1 25.00%
Vlastimil Babka 1 1.61% 1 25.00%
Johannes Weiner 1 1.61% 1 25.00%
Mel Gorman 1 1.61% 1 25.00%
Total 62 100.00% 4 100.00%

/*
 * page migration rate limiting control.
 * Do not migrate more than @pages_to_migrate in a @migrate_interval_millisecs
 * window of time. Default here says do not migrate more than 1280M per second.
 */

static unsigned int migrate_interval_millisecs __read_mostly = 100;

static unsigned int ratelimit_pages __read_mostly = 128 << (20 - PAGE_SHIFT);

/* Returns true if the node is migrate rate-limited after the update */


static bool numamigrate_update_ratelimit(pg_data_t *pgdat,
					unsigned long nr_pages)
{
	/*
         * Rate-limit the amount of data that is being migrated to a node.
         * Optimal placement is no good if the memory bus is saturated and
         * all the time is being spent migrating!
         */
	if (time_after(jiffies, pgdat->numabalancing_migrate_next_window)) {
		spin_lock(&pgdat->numabalancing_migrate_lock);
		pgdat->numabalancing_migrate_nr_pages = 0;
		pgdat->numabalancing_migrate_next_window = jiffies +
			msecs_to_jiffies(migrate_interval_millisecs);
		spin_unlock(&pgdat->numabalancing_migrate_lock);
	}
	if (pgdat->numabalancing_migrate_nr_pages > ratelimit_pages) {
		trace_mm_numa_migrate_ratelimit(current, pgdat->node_id,
								nr_pages);
		return true;
	}

	/*
         * This is an unlocked non-atomic update so errors are possible.
         * The consequences are failing to migrate when we potentiall should
         * have which is not severe enough to warrant locking. If it is ever
         * a problem, it can be converted to a per-cpu counter.
         */
	pgdat->numabalancing_migrate_nr_pages += nr_pages;
	return false;
}

Contributors
Person Tokens Prop Commits CommitProp
Mel Gorman 90 94.74% 6 85.71%
Peter Zijlstra 5 5.26% 1 14.29%
Total 95 100.00% 7 100.00%



static int numamigrate_isolate_page(pg_data_t *pgdat, struct page *page)
{
	int page_lru;

	VM_BUG_ON_PAGE(compound_order(page) && !PageTransHuge(page), page);

	/* Avoid migrating to a node that is nearly full */
	if (!migrate_balanced_pgdat(pgdat, 1UL << compound_order(page)))
		return 0;

	if (isolate_lru_page(page))
		return 0;

	/*
         * migrate_misplaced_transhuge_page() skips page migration's usual
         * check on page_count(), so we must do it here, now that the page
         * has been isolated: a GUP pin, or any other pin, prevents migration.
         * The expected page count is 3: 1 for page's mapcount and 1 for the
         * caller's pin and 1 for the reference taken by isolate_lru_page().
         */
	if (PageTransHuge(page) && page_count(page) != 3) {
		putback_lru_page(page);
		return 0;
	}

	page_lru = page_is_file_cache(page);
	mod_node_page_state(page_pgdat(page), NR_ISOLATED_ANON + page_lru,
				hpage_nr_pages(page));

	/*
         * Isolating the page has taken another reference, so the
         * caller's reference can be safely dropped without the page
         * disappearing underneath us during migration.
         */
	put_page(page);
	return 1;
}

Contributors
Person Tokens Prop Commits CommitProp
Mel Gorman 60 49.59% 6 66.67%
Hugh Dickins 30 24.79% 1 11.11%
Peter Zijlstra 28 23.14% 1 11.11%
Sasha Levin 3 2.48% 1 11.11%
Total 121 100.00% 9 100.00%



bool pmd_trans_migrating(pmd_t pmd)
{
	struct page *page = pmd_page(pmd);
	return PageLocked(page);
}

Contributors
Person Tokens Prop Commits CommitProp
Mel Gorman 24 100.00% 1 100.00%
Total 24 100.00% 1 100.00%

/*
 * Attempt to migrate a misplaced page to the specified destination
 * node. Caller is expected to have an elevated reference count on
 * the page that will be dropped by this function before returning.
 */


int migrate_misplaced_page(struct page *page, struct vm_area_struct *vma,
			   int node)
{
	pg_data_t *pgdat = NODE_DATA(node);
	int isolated;
	int nr_remaining;
	LIST_HEAD(migratepages);

	/*
         * Don't migrate file pages that are mapped in multiple processes
         * with execute permissions as they are probably shared libraries.
         */
	if (page_mapcount(page) != 1 && page_is_file_cache(page) &&
	    (vma->vm_flags & VM_EXEC))
		goto out;

	/*
         * Rate-limit the amount of data that is being migrated to a node.
         * Optimal placement is no good if the memory bus is saturated and
         * all the time is being spent migrating!
         */
	if (numamigrate_update_ratelimit(pgdat, 1))
		goto out;

	isolated = numamigrate_isolate_page(pgdat, page);
	if (!isolated)
		goto out;

	list_add(&page->lru, &migratepages);
	nr_remaining = migrate_pages(&migratepages, alloc_misplaced_dst_page,
				     NULL, node, MIGRATE_ASYNC,
				     MR_NUMA_MISPLACED);
	if (nr_remaining) {
		if (!list_empty(&migratepages)) {
			list_del(&page->lru);
			dec_node_page_state(page, NR_ISOLATED_ANON +
					page_is_file_cache(page));
			putback_lru_page(page);
		}
		isolated = 0;
	} else
		count_vm_numa_event(NUMA_PAGE_MIGRATE);
	BUG_ON(!list_empty(&migratepages));
	return isolated;

out:
	put_page(page);
	return 0;
}
Contributors
Person Tokens Prop Commits CommitProp
Mel Gorman 107 54.04% 5 55.56%
Peter Zijlstra 50 25.25% 1 11.11%
JoonSoo Kim 30 15.15% 1 11.11%
Hugh Dickins 9 4.55% 1 11.11%
David Rientjes 2 1.01% 1 11.11%
Total 198 100.00% 9 100.00%

#endif /* CONFIG_NUMA_BALANCING */

#if defined(CONFIG_NUMA_BALANCING) && defined(CONFIG_TRANSPARENT_HUGEPAGE)
/*
 * Migrates a THP to a given target node. page must be locked and is unlocked
 * before returning.
 */


int migrate_misplaced_transhuge_page(struct mm_struct *mm,
				struct vm_area_struct *vma,
				pmd_t *pmd, pmd_t entry,
				unsigned long address,
				struct page *page, int node)
{
	spinlock_t *ptl;
	pg_data_t *pgdat = NODE_DATA(node);
	int isolated = 0;
	struct page *new_page = NULL;
	int page_lru = page_is_file_cache(page);
	unsigned long mmun_start = address & HPAGE_PMD_MASK;
	unsigned long mmun_end = mmun_start + HPAGE_PMD_SIZE;
	pmd_t orig_entry;

	/*
         * Rate-limit the amount of data that is being migrated to a node.
         * Optimal placement is no good if the memory bus is saturated and
         * all the time is being spent migrating!
         */
	if (numamigrate_update_ratelimit(pgdat, HPAGE_PMD_NR))
		goto out_dropref;

	new_page = alloc_pages_node(node,
		(GFP_TRANSHUGE_LIGHT | __GFP_THISNODE),
		HPAGE_PMD_ORDER);
	if (!new_page)
		goto out_fail;
	prep_transhuge_page(new_page);

	isolated = numamigrate_isolate_page(pgdat, page);
	if (!isolated) {
		put_page(new_page);
		goto out_fail;
	}
	/*
         * We are not sure a pending tlb flush here is for a huge page
         * mapping or not. Hence use the tlb range variant
         */
	if (mm_tlb_flush_pending(mm))
		flush_tlb_range(vma, mmun_start, mmun_end);

	/* Prepare a page as a migration target */
	__SetPageLocked(new_page);
	__SetPageSwapBacked(new_page);

	/* anon mapping, we can simply copy page->mapping to the new page: */
	new_page->mapping = page->mapping;
	new_page->index = page->index;
	migrate_page_copy(new_page, page);
	WARN_ON(PageLRU(new_page));

	/* Recheck the target PMD */
	mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);
	ptl = pmd_lock(mm, pmd);
	if (unlikely(!pmd_same(*pmd, entry) || page_count(page) != 2)) {
fail_putback:
		spin_unlock(ptl);
		mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);

		/* Reverse changes made by migrate_page_copy() */
		if (TestClearPageActive(new_page))
			SetPageActive(page);
		if (TestClearPageUnevictable(new_page))
			SetPageUnevictable(page);

		unlock_page(new_page);
		put_page(new_page);		/* Free it */

		/* Retake the callers reference and putback on LRU */
		get_page(page);
		putback_lru_page(page);
		mod_node_page_state(page_pgdat(page),
			 NR_ISOLATED_ANON + page_lru, -HPAGE_PMD_NR);

		goto out_unlock;
	}

	orig_entry = *pmd;
	entry = mk_huge_pmd(new_page, vma->vm_page_prot);
	entry = maybe_pmd_mkwrite(pmd_mkdirty(entry), vma);

	/*
         * Clear the old entry under pagetable lock and establish the new PTE.
         * Any parallel GUP will either observe the old page blocking on the
         * page lock, block on the page table lock or observe the new page.
         * The SetPageUptodate on the new page and page_add_new_anon_rmap
         * guarantee the copy is visible before the pagetable update.
         */
	flush_cache_range(vma, mmun_start, mmun_end);
	page_add_anon_rmap(new_page, vma, mmun_start, true);
	pmdp_huge_clear_flush_notify(vma, mmun_start, pmd);
	set_pmd_at(mm, mmun_start, pmd, entry);
	update_mmu_cache_pmd(vma, address, &entry);

	if (page_count(page) != 2) {
		set_pmd_at(mm, mmun_start, pmd, orig_entry);
		flush_pmd_tlb_range(vma, mmun_start, mmun_end);
		mmu_notifier_invalidate_range(mm, mmun_start, mmun_end);
		update_mmu_cache_pmd(vma, address, &entry);
		page_remove_rmap(new_page, true);
		goto fail_putback;
	}

	mlock_migrate_page(new_page, page);
	page_remove_rmap(page, true);
	set_page_owner_migrate_reason(new_page, MR_NUMA_MISPLACED);

	spin_unlock(ptl);
	mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);

	/* Take an "isolate" reference and put new page on the LRU. */
	get_page(new_page);
	putback_lru_page(new_page);

	unlock_page(new_page);
	unlock_page(page);
	put_page(page);			/* Drop the rmap reference */
	put_page(page);			/* Drop the LRU isolation reference */

	count_vm_events(PGMIGRATE_SUCCESS, HPAGE_PMD_NR);
	count_vm_numa_events(NUMA_PAGE_MIGRATE, HPAGE_PMD_NR);

	mod_node_page_state(page_pgdat(page),
			NR_ISOLATED_ANON + page_lru,
			-HPAGE_PMD_NR);
	return isolated;

out_fail:
	count_vm_events(PGMIGRATE_FAIL, HPAGE_PMD_NR);
out_dropref:
	ptl = pmd_lock(mm, pmd);
	if (pmd_same(*pmd, entry)) {
		entry = pmd_modify(entry, vma->vm_page_prot);
		set_pmd_at(mm, mmun_start, pmd, entry);
		update_mmu_cache_pmd(vma, address, &entry);
	}
	spin_unlock(ptl);

out_unlock:
	unlock_page(page);
	put_page(page);
	return 0;
}
Contributors
Person Tokens Prop Commits CommitProp
Mel Gorman 586 89.19% 10 38.46%
Kirill A. Shutemov 24 3.65% 5 19.23%
Hugh Dickins 24 3.65% 3 11.54%
Joerg Roedel 9 1.37% 1 3.85%
Vlastimil Babka 8 1.22% 2 7.69%
Aneesh Kumar K.V 3 0.46% 2 7.69%
Johannes Weiner 2 0.30% 2 7.69%
Stephen Rothwell 1 0.15% 1 3.85%
Total 657 100.00% 26 100.00%

#endif /* CONFIG_NUMA_BALANCING */

#endif /* CONFIG_NUMA */
Overall Contributors
Person Tokens Prop Commits CommitProp
Christoph Lameter 1822 24.96% 20 9.66%
Mel Gorman 1396 19.13% 38 18.36%
Naoya Horiguchi 740 10.14% 14 6.76%
MinChan Kim 728 9.97% 5 2.42%
Brice Goglin 613 8.40% 6 2.90%
Hugh Dickins 459 6.29% 19 9.18%
Peter Zijlstra 239 3.27% 3 1.45%
Dave Hansen 204 2.79% 1 0.48%
Kirill A. Shutemov 187 2.56% 12 5.80%
Nicholas Piggin 102 1.40% 7 3.38%
JoonSoo Kim 73 1.00% 4 1.93%
David Rientjes 46 0.63% 2 0.97%
Motohiro Kosaki 45 0.62% 4 1.93%
Vlastimil Babka 43 0.59% 5 2.42%
Rafael Aquini 42 0.58% 3 1.45%
David Howells 41 0.56% 5 2.42%
Linus Torvalds 40 0.55% 2 0.97%
H. Peter Anvin 33 0.45% 1 0.48%
Geert Uytterhoeven 29 0.40% 1 0.48%
Heiko Carstens 28 0.38% 1 0.48%
Vladimir Davydov 27 0.37% 1 0.48%
Andrea Arcangeli 27 0.37% 5 2.42%
Lin Ming 24 0.33% 1 0.48%
Johannes Weiner 23 0.32% 4 1.93%
Kamezawa Hiroyuki 22 0.30% 4 1.93%
Rik Van Riel 21 0.29% 1 0.48%
Eric W. Biedermann 20 0.27% 1 0.48%
David Shaohua Li 18 0.25% 2 0.97%
Aneesh Kumar K.V 17 0.23% 3 1.45%
David P. Quigley 16 0.22% 1 0.48%
Tony Lu 15 0.21% 1 0.48%
Gleb Natapov 14 0.19% 1 0.48%
Cyrill V. Gorcunov 14 0.19% 1 0.48%
Sasha Levin 14 0.19% 2 0.97%
Wanpeng Li 13 0.18% 1 0.48%
Benjamin LaHaise 13 0.18% 1 0.48%
Lee Schermerhorn 11 0.15% 1 0.48%
Andi Kleen 10 0.14% 2 0.97%
Richard Weinberger 10 0.14% 1 0.48%
Joerg Roedel 9 0.12% 1 0.48%
Konstantin Khlebnikov 6 0.08% 1 0.48%
Jacobo Giralt 5 0.07% 1 0.48%
Rabin Vincent 5 0.07% 1 0.48%
Yisheng Xie 4 0.05% 1 0.48%
Greg Thelen 4 0.05% 1 0.48%
Tejun Heo 3 0.04% 1 0.48%
Pavel Emelyanov 3 0.04% 1 0.48%
Michal Nazarewicz 3 0.04% 1 0.48%
Ingo Molnar 3 0.04% 1 0.48%
Adrian Bunk 3 0.04% 1 0.48%
Gerald Schaefer 2 0.03% 1 0.48%
Hillf Danton 2 0.03% 1 0.48%
Leonid Yegoshin 2 0.03% 1 0.48%
Stephen Rothwell 2 0.03% 2 0.97%
Wang Sheng-Hui 1 0.01% 1 0.48%
Paul Gortmaker 1 0.01% 1 0.48%
Jianguo Wu 1 0.01% 1 0.48%
Lai Jiangshan 1 0.01% 1 0.48%
Total 7299 100.00% 207 100.00%
Directory: mm

Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with cregit.
Person	Tokens	Prop	Commits	CommitProp
Christoph Lameter	11	78.57%	1	50.00%
Mel Gorman	3	21.43%	1	50.00%
Total	14	100.00%	2	100.00%
cregit-Linux how code gets into the kernel

Release 4.11 mm/migrate.c

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