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[Xen-devel] [PATCH] Fix xc_tbuf_enable assumption.

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Subject: [Xen-devel] [PATCH] Fix xc_tbuf_enable assumption.
From: Atsushi SAKAI <sakaia@xxxxxxxxxxxxxx>
Date: Wed, 24 May 2006 21:36:02 +0900
Delivery-date: Wed, 24 May 2006 05:37:02 -0700
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Hi, All!

 This is a patch which needs discussion.
 Currently xc_tbuf_enable assumed tb_init_done = 0.
But Sometimes already on 

For example(xenmon.py(xenbaked) and xentrace).
These two programs assues tb_init_done =0 at start time.

Currently xenbaked care the problem by setting tb_init_done=0 at exit time.
But xentrace does not care the problem.
Then error occured!(Cannot see the trace buffer.)

I added a code in xc_tbuf_enable to permit tb_init_done=1.
And I added to check trace buffer region is already allocated or not
by using xc_tbuf_get_size.

But This solution problem remains,
1) It cannot change the trace buffer size by using xc_tbuf_enable
   If we do, we need to add more code to freeing xen buffer.

As other option.(at application layer)
Adding previous command tbctl.  
This command switches tb_init_done =0 and 1.

Comments are appreciated.

This problem occured in following steps.

  tb_init_done = 1
2)xentrace (problem occured at xc_tbuf_enable see above)

After xentrace work, this problem occured.

Signed-off-by: Atsushi SAKAI <sakaia@xxxxxxxxxxxxxx>

Atsushi Sakai

Attachment: xc_enable.patch
Description: Binary data

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