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[Xen-devel] Re: questions about the block backend/frontend driver

To: xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: [Xen-devel] Re: questions about the block backend/frontend driver
From: "Yuming fang" <fangyuming.leo@xxxxxxxxx>
Date: Tue, 9 Sep 2008 20:43:07 +0800
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Nobody answer these questions? I want to know if I could implement the I/O disk scheduling in Xen and then I could not modify the corresponding code(I/O Scheduling algorithms) of Linux Kernel?

2008/9/8 Yuming fang <fangyuming.leo@xxxxxxxxx>
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.

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