Hi, Everyone,

I am trying to understand the code of the block backend/frontend driver. I konw the blkback and blkfront communicate with each other through event channel and buffer ring. But there are some questions I could not understand.

1. When dom0 receive one disk request from domU1 and another disk request from domU2 simultaneously, how these two disk requests are pushed into Linux Kernel I/O Scheduler? How the Xen sort them before pushing them into the Linux Kernel I/O Scheduler?

2. Is there a disk request queue in the Xen to hold these disk requests, so that the Xen could only push the disk requests in the queue into the linux kernel I/O Scheduler?

I would appreciate it very much if anyone could give me some help.

Yuming