linux-4.4.1/gfpflags_to_migratetype() の履歴(No.1)

• 履歴一覧
• 差分 を表示
• 現在との差分 を表示
• ソース を表示
• linux-4.4.1/gfpflags_to_migratetype() へ行く。
  • 1 (2017-09-25 (月) 13:05:27)
  • 2 (2017-09-25 (月) 13:21:21)

参照元†

• linux-4.4.1/__alloc_pages_nodemask()

説明†

• パス: linux-4.4.1/include/linux/gfp.h

• FIXME: これは何？
  • 説明

引数†

• const gfp_t gfp_flags
  • linux-4.4.1/gfp_t

返り値†

• int

参考†

enum {
	MIGRATE_UNMOVABLE,
	MIGRATE_MOVABLE,
	MIGRATE_RECLAIMABLE,
	MIGRATE_PCPTYPES,	/* the number of types on the pcp lists */
	MIGRATE_HIGHATOMIC = MIGRATE_PCPTYPES,
#ifdef CONFIG_CMA
	/*
	 * MIGRATE_CMA migration type is designed to mimic the way
	 * ZONE_MOVABLE works.  Only movable pages can be allocated
	 * from MIGRATE_CMA pageblocks and page allocator never
	 * implicitly change migration type of MIGRATE_CMA pageblock.
	 *
	 * The way to use it is to change migratetype of a range of
	 * pageblocks to MIGRATE_CMA which can be done by
	 * __free_pageblock_cma() function.  What is important though
	 * is that a range of pageblocks must be aligned to
	 * MAX_ORDER_NR_PAGES should biggest page be bigger then
	 * a single pageblock.
	 */
	MIGRATE_CMA,
#endif
#ifdef CONFIG_MEMORY_ISOLATION
	MIGRATE_ISOLATE,	/* can't allocate from here */
#endif
	MIGRATE_TYPES
};

実装†

/* Convert GFP flags to their corresponding migrate type */
#define GFP_MOVABLE_MASK (__GFP_RECLAIMABLE|__GFP_MOVABLE)
#define GFP_MOVABLE_SHIFT 3

static inline int gfpflags_to_migratetype(const gfp_t gfp_flags)
{
	VM_WARN_ON((gfp_flags & GFP_MOVABLE_MASK) == GFP_MOVABLE_MASK);
	BUILD_BUG_ON((1UL << GFP_MOVABLE_SHIFT) != ___GFP_MOVABLE);
	BUILD_BUG_ON((___GFP_MOVABLE >> GFP_MOVABLE_SHIFT) != MIGRATE_MOVABLE);

• • linux-4.4.1/VM_WARN_ON()
  • linux-4.4.1/BUILD_BUG_ON()
  • linux-4.4.1/___GFP_MOVABLE

	if (unlikely(page_group_by_mobility_disabled))
		return MIGRATE_UNMOVABLE;

• • linux-4.4.1/unlikely()
  • linux-4.4.1/page_group_by_mobility_disabled(global)

	/* Group based on mobility */
	return (gfp_flags & GFP_MOVABLE_MASK) >> GFP_MOVABLE_SHIFT;
}
#undef GFP_MOVABLE_MASK
#undef GFP_MOVABLE_SHIFT

コメント†