mm: Convert page migration to XArray (89eb946a) · Commits · 戴 / test

mm/migrate.c

+18 −30

Original line number	Diff line number	Diff line
		@@ -323,7 +323,7 @@ void __migration_entry_wait(struct mm_struct mm, pte_t ptep,
		page = migration_entry_to_page(entry);

		/*
		* Once radix-tree replacement of page migration started, page_count
		* Once page cache 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
		@@ -438,10 +438,10 @@ int migrate_page_move_mapping(struct address_space *mapping,
		struct buffer_head *head, enum migrate_mode mode,
		int extra_count)
		{
		XA_STATE(xas, &mapping->i_pages, page_index(page));
		struct zone oldzone, newzone;
		int dirty;
		int expected_count = 1 + extra_count;
		void **pslot;

		/*
		* Device public or private pages have an extra refcount as they are
		@@ -467,21 +467,16 @@ int migrate_page_move_mapping(struct address_space *mapping,
		oldzone = page_zone(page);
		newzone = page_zone(newpage);

		xa_lock_irq(&mapping->i_pages);

		pslot = radix_tree_lookup_slot(&mapping->i_pages,
		page_index(page));
		xas_lock_irq(&xas);

		expected_count += hpage_nr_pages(page) + page_has_private(page);
		if (page_count(page) != expected_count \|\|
		radix_tree_deref_slot_protected(pslot,
		&mapping->i_pages.xa_lock) != page) {
		xa_unlock_irq(&mapping->i_pages);
		if (page_count(page) != expected_count \|\| xas_load(&xas) != page) {
		xas_unlock_irq(&xas);
		return -EAGAIN;
		}

		if (!page_ref_freeze(page, expected_count)) {
		xa_unlock_irq(&mapping->i_pages);
		xas_unlock_irq(&xas);
		return -EAGAIN;
		}

		@@ -495,7 +490,7 @@ int migrate_page_move_mapping(struct address_space *mapping,
		if (mode == MIGRATE_ASYNC && head &&
		!buffer_migrate_lock_buffers(head, mode)) {
		page_ref_unfreeze(page, expected_count);
		xa_unlock_irq(&mapping->i_pages);
		xas_unlock_irq(&xas);
		return -EAGAIN;
		}

		@@ -523,16 +518,13 @@ int migrate_page_move_mapping(struct address_space *mapping,
		SetPageDirty(newpage);
		}

		radix_tree_replace_slot(&mapping->i_pages, pslot, newpage);
		xas_store(&xas, newpage);
		if (PageTransHuge(page)) {
		int i;
		int index = page_index(page);

		for (i = 1; i < HPAGE_PMD_NR; i++) {
		pslot = radix_tree_lookup_slot(&mapping->i_pages,
		index + i);
		radix_tree_replace_slot(&mapping->i_pages, pslot,
		newpage + i);
		xas_next(&xas);
		xas_store(&xas, newpage + i);
		}
		}

		@@ -543,7 +535,7 @@ int migrate_page_move_mapping(struct address_space *mapping,
		*/
		page_ref_unfreeze(page, expected_count - hpage_nr_pages(page));

		xa_unlock(&mapping->i_pages);
		xas_unlock(&xas);
		/* Leave irq disabled to prevent preemption while updating stats */

		/*
		@@ -583,22 +575,18 @@ EXPORT_SYMBOL(migrate_page_move_mapping);
		int migrate_huge_page_move_mapping(struct address_space *mapping,
		struct page newpage, struct page page)
		{
		XA_STATE(xas, &mapping->i_pages, page_index(page));
		int expected_count;
		void **pslot;

		xa_lock_irq(&mapping->i_pages);

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

		xas_lock_irq(&xas);
		expected_count = 2 + page_has_private(page);
		if (page_count(page) != expected_count \|\|
		radix_tree_deref_slot_protected(pslot, &mapping->i_pages.xa_lock) != page) {
		xa_unlock_irq(&mapping->i_pages);
		if (page_count(page) != expected_count \|\| xas_load(&xas) != page) {
		xas_unlock_irq(&xas);
		return -EAGAIN;
		}

		if (!page_ref_freeze(page, expected_count)) {
		xa_unlock_irq(&mapping->i_pages);
		xas_unlock_irq(&xas);
		return -EAGAIN;
		}

		@@ -607,11 +595,11 @@ int migrate_huge_page_move_mapping(struct address_space *mapping,

		get_page(newpage);

		radix_tree_replace_slot(&mapping->i_pages, pslot, newpage);
		xas_store(&xas, newpage);

		page_ref_unfreeze(page, expected_count - 1);

		xa_unlock_irq(&mapping->i_pages);
		xas_unlock_irq(&xas);

		return MIGRATEPAGE_SUCCESS;
		}

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