Re: [Xen-devel] Re: [PATCH 2/6] trace: fix T_INFO_FIRST_OFFSET

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

I've lost track of all these trace patches. Please send a new set of patches
with finalised Sign-offs and Acks as appropriate when you reach agreement.

 -- Keir

On 30/06/2010 17:12, "George Dunlap" <George.Dunlap@xxxxxxxxxxxxx> wrote:

> Oops, please use this version, which used the appropraite gkprintk()
> settings...
> 
>  -George
> 
> On Wed, Jun 30, 2010 at 5:10 PM, George Dunlap
> <George.Dunlap@xxxxxxxxxxxxx> wrote:
>> Here's a version that calculates t_info_first_offset during
>> initialization, based on the actual layout of struct t_info and
>> NR_CPUs.
>> 
>>  -George
>> 
>> On Wed, Jun 30, 2010 at 4:28 PM, George Dunlap
>> <george.dunlap@xxxxxxxxxxxxx> wrote:
>>> Jan Beulich wrote:
>>>> 
>>>> That part your patch doesn't address either - rather than
>>>> sizeof(uint16_t) as the first part of the expression you'd need to
>>>> use sizeof(struct t_info) or offsetof(struct t_info, mfn_offset).
>>>> 
>>> 
>>> I was assuming that when someone changed struct t_info that they'd modify
>>> this macro as well; I suppose then that the two complaints are really
>>> different aspects of the same one -- that it might not be clear to the
>>> person who adjusts struct t_info how to translate those changes into
>>> T_INFO_FIRST_OFFSET.  I think this way is more clear.
>>> 
>>> I suppose even better might be to calculate t_info.mfn_mfn_offset[NR_CPUS]
>>> (or perhaps ...[num_possible_cpus]).  Hmm... let me see what I can come up
>>> with.
>>>> 
>>>> Btw., didn't we agree that public headers shouldn't make use of
>>>> language extensions? struct t_info uses a variable sized array,
>>>> which is an extension (standard only in C99).
>>>> 
>>> 
>>> I'm not an expert in this.  It's lot more hassle to lay out the data the way
>>> I'd like without it.  I'll defer judgment to Keir.
>>> 
>>> -George
>>> 
>>> _______________________________________________
>>> Xen-devel mailing list
>>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>>> http://lists.xensource.com/xen-devel
>>> 
>> 



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