From mboxrd@z Thu Jan  1 00:00:00 1970
From: mathieu.desnoyers@efficios.com (Mathieu Desnoyers)
Date: Wed, 16 Jun 2010 09:46:52 -0400
Subject: [ltt-dev] [PATCH RFC] Force build failure on unknown
	architectures
In-Reply-To: <4C18C236.3030100@redhat.com>
References: <20100615231423.GA16064@linux.vnet.ibm.com>
	<4C1812E1.5080103@redhat.com>
	<20100616001228.GM2304@linux.vnet.ibm.com>
	<4C18C236.3030100@redhat.com>
Message-ID: <20100616134651.GC25401@Krystal>

* Paolo Bonzini (pbonzini at redhat.com) wrote:
> On 06/16/2010 02:12 AM, Paul E. McKenney wrote:
>> On Wed, Jun 16, 2010 at 01:55:13AM +0200, Paolo Bonzini wrote:
>>> On 06/16/2010 01:14 AM, Paul E. McKenney wrote:
>>>> Create urcu/arch_unknown.h and urcu/uatomic_arch_unknown.h, which
>>>> contain only #error statements and explanatory comments.  This forces
>>>> build failures on unrecognized architectures in preference to trying
>>>> to guess at what operations might be safe on such architectures.
>>>>
>>>> One other semi-feasible alternative is to use hashed arrays of locks
>>>> that are acquired with signals disabled.  However, this seems a bit
>>>> too ornate, especially for architectures for which the gcc __sync_
>>>> primitives work correctly.
>>>
>>> ia64 is one.
>>
>> Does ia64 work with the current code?  (My guess is "no" -- I believe
>> that you would get build errors.  But I have been surprised before!)
>
> I don't know. :)
>
>> If my guess is correct, my thought would be to create urcu/arch_gcc.h
>> and urcu/uatomic_arch_gcc.h files with the appropriate definitions
>> based on __sync_ primitives.  If you can test on IA64, I would also
>> be happy to add support for it based on these new files.
>
> Sure, thanks!

So given the #error on unknown removes ia64 support, I'll wait for a patch
resend before I merge this patch along with the "gcc-based" ia64 support. Is
that OK ? So Paul, could you resend this patch along with the ia64 support based
on gcc ?

Thanks,

Mathieu

>
> Paolo

-- 
Mathieu Desnoyers
Operating System Efficiency R&D Consultant
EfficiOS Inc.
http://www.efficios.com