From mboxrd@z Thu Jan  1 00:00:00 1970
From: Olaf Hering <olaf@aepfle.de>
Subject: Re: [PATCH 1 of 5] xentrace: fix t_info_pages
 calculation for the default case
Date: Thu, 24 Mar 2011 17:03:27 +0100
Message-ID: <20110324160327.GA27980@aepfle.de>
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To: George Dunlap <george.dunlap@eu.citrix.com>
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On Thu, Mar 24, George Dunlap wrote:

> Then it's really clear when looking at it what the inputs and outputs of
> each line is supposed to be.

George,

lets not overdo things. The formula I came up with, based on the initial
code, is even slightly incorrect. It may allocate more than needed.
Each cpu has some pages/mfns stored as uint32_t. That list is stored
with an offset at tinfo. So its more like:
num_online_cpus() * pages * sizeof(uint32_t) + t_info_first_offset;
And that number of bytes is now correctly converted to pages with
PFN_UP. 

        t_info_words = num_online_cpus() * pages * sizeof(uint32_t);
        t_info_pages = PFN_UP(t_info_first_offset + t_info_words);

(Modulo things I missed.)

Olaf