mm: migrate: Introduce migrate_misplaced_page() (7039e1db) · Commits · 戴 / test

include/linux/migrate.h

+11 −0

Original line number	Diff line number	Diff line
		@@ -13,6 +13,7 @@ enum migrate_reason {
		MR_MEMORY_HOTPLUG,
		MR_SYSCALL, /* also applies to cpusets */
		MR_MEMPOLICY_MBIND,
		MR_NUMA_MISPLACED,
		MR_CMA
		};

		@@ -73,4 +74,14 @@ static inline int migrate_huge_page_move_mapping(struct address_space *mapping,
		#define fail_migrate_page NULL

		#endif /* CONFIG_MIGRATION */

		#ifdef CONFIG_NUMA_BALANCING
		extern int migrate_misplaced_page(struct page *page, int node);
		#else
		static inline int migrate_misplaced_page(struct page *page, int node)
		{
		return -EAGAIN; /* can't migrate now */
		}
		#endif /* CONFIG_NUMA_BALANCING */

		#endif /* _LINUX_MIGRATE_H */

mm/migrate.c

+106 −2

Original line number	Diff line number	Diff line
		@@ -282,7 +282,7 @@ static int migrate_page_move_mapping(struct address_space *mapping,
		struct page newpage, struct page page,
		struct buffer_head *head, enum migrate_mode mode)
		{
		int expected_count;
		int expected_count = 0;
		void **pslot;

		if (!mapping) {
		@@ -1415,4 +1415,108 @@ int migrate_vmas(struct mm_struct mm, const nodemask_t to,
		}
		return err;
		}
		#endif

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

		if (!populated_zone(zone))
		continue;

		if (zone->all_unreclaimable)
		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;
		}

		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_exact_node(nid,
		(GFP_HIGHUSER_MOVABLE \| GFP_THISNODE \|
		__GFP_NOMEMALLOC \| __GFP_NORETRY \|
		__GFP_NOWARN) &
		~GFP_IOFS, 0);
		return newpage;
		}

		/*
		* 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, int node)
		{
		int isolated = 0;
		LIST_HEAD(migratepages);

		/*
		* Don't migrate pages that are mapped in multiple processes.
		* TODO: Handle false sharing detection instead of this hammer
		*/
		if (page_mapcount(page) != 1) {
		put_page(page);
		goto out;
		}

		/* Avoid migrating to a node that is nearly full */
		if (migrate_balanced_pgdat(NODE_DATA(node), 1)) {
		int page_lru;

		if (isolate_lru_page(page)) {
		put_page(page);
		goto out;
		}
		isolated = 1;

		/*
		* Page is isolated which takes a reference count so now the
		* callers reference can be safely dropped without the page
		* disappearing underneath us during migration
		*/
		put_page(page);

		page_lru = page_is_file_cache(page);
		inc_zone_page_state(page, NR_ISOLATED_ANON + page_lru);
		list_add(&page->lru, &migratepages);
		}

		if (isolated) {
		int nr_remaining;

		nr_remaining = migrate_pages(&migratepages,
		alloc_misplaced_dst_page,
		node, false, MIGRATE_ASYNC,
		MR_NUMA_MISPLACED);
		if (nr_remaining) {
		putback_lru_pages(&migratepages);
		isolated = 0;
		}
		}
		BUG_ON(!list_empty(&migratepages));
		out:
		return isolated;
		}
		#endif /* CONFIG_NUMA_BALANCING */

		#endif /* CONFIG_NUMA */

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