compact

函数名称：Number of free order-0 pages that should be available above given watermark* to make sure compaction has reasonable chance of not running out of free* pages that it needs to isolate as migration target during its work.

函数原型：static inline unsigned long compact_gap(unsigned int order)

返回类型：unsigned long

参数：

类型	参数	名称
unsigned int	order

**调用者**
名称	描述
should_continue_reclaim	Reclaim/compaction is used for high-order allocation requests. It reclaims* order-0 pages before compacting the zone. should_continue_reclaim() returns* true if more pages should be reclaimed such that when the page allocator
compaction_ready	Returns true if compaction should go ahead for a costly-order request, or* the allocation would already succeed without compaction. Return false if we* should reclaim first.
kswapd_shrink_node	kswapd shrinks a node of pages that are at or below the highest usable* zone that is currently unbalanced.* Returns true if kswapd scanned at least the requested number of pages to* reclaim or if the lack of progress was due to pages under writeback.

函数逻辑报告