elevator.c.txt

来自「linux内核学习笔记 希望想看的人可以很快下载到」· 文本 代码 · 共 44 行

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相关文件
	/drivers/block/ll_rw_dev.c


****************************基本函数************************************
(1)void elevator_init(elevator_t * elevator, elevator_t type)
	//对电梯合并算法进行设置。目前有两种，一种linux,一种noop


(2)int elevator_noop_merge(request_queue_t *q, struct request **req,
                        struct list_head * head,
                        struct buffer_head *bh, int rw,
                        int max_sectors)
	while ((entry = entry->prev) != head)	//扫描整个请求处理队列
		if (__rq->cmd != rw)
	                       continue;
                if (__rq->rq_dev != bh->b_rdev)
               	        continue;
	               if (__rq->nr_sectors + count > max_sectors)
                        continue;
	               if (__rq->waiting)
                        continue;	//找到合适的request
		
		//按照request中的数据看新到的bh放到哪里合适
		if (__rq->sector + __rq->nr_sectors == bh->b_rsector) {
	                       *req = __rq;
                        return ELEVATOR_BACK_MERGE;
               	} else if (__rq->sector - count == bh->b_rsector) {
                       	*req = __rq;
	                       return ELEVATOR_FRONT_MERGE;
                }	


(3)int elevator_linus_merge(request_queue_t *q, struct request **req,	//默认合并处理函数
                         struct list_head * head,
                         struct buffer_head *bh, int rw,
                         int max_sectors)
	



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