Re: [Xen-devel] ioctl and Xen

[Kuriakose Mathew <kmathew123@xxxxxxxxx>]

Hi 
   Even I am looking for something similar. I came upon xenstore ,
through which we can write a particular value to a key and then read
the corresponding value. Even there is a concept of watch in xenstore
which gives a notification as to ,a value corresponding to a key has
changed. But I could read and write only from the userspace. If you
could read a key's value from kernel space , you are done. If you get
anything in this direction do inform.


-Mathew

On Sat, Aug 8, 2009 at 2:29 AM, Derek Riley <derek.riley@xxxxxxxxxxxxxxxxxxx> wrote:

Thanks for the suggestion.  It appears to me that the xentrace only implements one-way communication between the kernel and user space, but I need 2 way communication. 

I know it is not the "right" way to do it, but is there a way to read/write a file within the scheduler?  I am working on a 1-off implementation for a specialized project that will never make it into the main kernel. 

Thanks
--Derek

On Fri, Aug 7, 2009 at 3:22 PM, Dulloor <dulloor@xxxxxxxxx> wrote:

You can look at the way trace-bufs are implemented in xentrace. You will find xentrace in xen/tools.

-dulloor

On Fri, Aug 7, 2009 at 3:36 PM, Derek Riley <derek.riley@xxxxxxxxxxxxxxxxxxx> wrote:

Thanks for your reply.  I am familiar with the files you listed, but they do not do what I need, nor do I see how they could be modified to do what I want (although I may be missing something). 

I am trying to pass simple information in and out of the scheduler while it is running to a user process for monitoring and control.  I just need an IPC method that is fast so it won't bog down the scheduler or the user space process.  Any thoughts?  Thanks
--Derek

On Fri, Aug 7, 2009 at 2:29 PM, Marco Tizzoni <marco.tizzoni@xxxxxxxxx> wrote:

On Fri, Aug 7, 2009 at 7:54 PM, Derek
Riley<derek.riley@xxxxxxxxxxxxxxxxxxx> wrote:
> Hello developers-
> I am trying to modify the Xen Hypervisor kernel to pass information to and
> from a user space program to the domain scheduler (sched_credit),

I'm not experienced but I think you could have a look at:

xen/include/public/domctl.h
xen/include/public/sched.h
xen/include/public/sched-if.h
xen/common/sched_credit.c
tools/libxc/xc_csched.c

m-

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