随笔分类 -  Linux 0.11内核阅读心得

摘要：110repeat: 111/* we don't allow the write-requests to fill up the queue completely: 112 * we want some room for reads: they take precedence. The last third 113 * of the requests are only for reads. 114 */ 115 if (rw == READ) 116 req = request+NR_REQUEST; 117 else 118 ... 阅读全文

摘要：42 static inline void lock_buffer(struct buffer_head * bh) 43 { 44 cli(); 45 while (bh->b_lock) 46 sleep_on(&bh->b_wait); 47 bh->b_lock=1; 48 sti(); 49 }摘自kernel/blk_drv/ll_rw_blk.c本篇文章主要讨论一下此函数有没有必要关闭中断。Linux 0.11内核在内核态是不可抢占的，因为时钟中断的处理过程中发现被打断的执行序列正处在内核中，则不引发进程切换，也就是仍然返回原来的... 阅读全文