Re: [PATCH] - Improve SN2 TLB flushing algorithms

From: Peter Chubb <>
Date: 2004-01-29 10:57:49
>>>>> "Jack" == Jack Steiner <> writes:

Jack> On Wed, Jan 28, 2004 at 09:17:59PM +0000, Christoph Hellwig
Jack> wrote:
>> On Wed, Jan 28, 2004 at 02:59:12PM -0600, Jack Steiner wrote: >
>> +#ifdef CONFIG_NUMA > + cpus_clear(mm->cpu_vm_mask); > +#endif
>> I really hate this ifdefs all over the place.  Does this really
>> hurt that much on non-NUMA systems?  Also SN2 seems to use this
>> code always so CONFIG_NUMA looks like the wrong ifdef to me.

Jack> Are you suggesting that we remove the #ifdef OR hide the code in
Jack> a function that, depending on config options, may or may not do
Jack> anything?

Jack> The code is needed on kernels built for SN2. That includes both
Jack> CONFIG_IA64_GENERIC & CONFIG_IA64_SGI_SN2. I agree that
Jack> CONFIG_NUMA is not a great choice but nothing else seemed
Jack> appropriate.

As CONFIG_IA64_GENERIC is a superset of CONFIG_IA64_SGI_SN2
why not make CONFIG_IA64_GENERIC turn on CONFIG_IA64_SGI_SN2   and
then only test for the latter.

And yes, using a function that disappears or does nothing on platforms
for which it is inappropriate is a better approach than littering
#ifdefs though the code.

Dr Peter Chubb  peterc AT
The technical we do immediately,  the political takes *forever*
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Received on Wed Jan 28 19:01:26 2004

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