内核的哪个部分管理io请求？

Question

我知道Linux /O栈中的块I/O层管理和调度I/O请求。但我不知道这段代码在哪里。实际上，我希望看到内核中对应于这一层的代码部分。

Answer 1

IO的调度是从调用blk_finish_plug函数开始的，它本身将调用IO调度程序的elevator_add_req_fn方法。

这是一个调用此函数以添加新IOs的写回处理的示例：

#0  deadline_add_request at block/deadline-iosched.c:102
#1  __elv_add_request at block/elevator.c:717
#2  blk_flush_plug_list at block/blk-core.c:2746
#3  blk_finish_plug at block/blk-core.c:2762
#4  generic_writepages at mm/page-writeback.c:1052
#5  do_writepages at mm/page-writeback.c:1065
#6  writeback_single_inode at fs/fs-writeback.c:388
#7  writeback_sb_inodes at fs/fs-writeback.c:549
#8  writeback_inodes_wb at fs/fs-writeback.c:592
#9  wb_writeback at fs/fs-writeback.c:724
#10 wb_check_background at fs/fs-writeback.c:804
#11 wb_do_writeback at fs/fs-writeback.c:879
#12 bdi_writeback_thread at fs/fs-writeback.c:913
#13 kthread at kernel/kthread.c:96

您可以查看堆栈跟踪中提到的文件，特别是blk-core.c文件的blk_finish_plug方法。您可以在https://lwn.net/Articles/438256/上找到更多关于插入工作方式的详细信息。