Re: [PATCH net-2.6] Re: rib_trie / Fix inflate_threshold_root. Now=15 size=11 bits

[Jarek Poplawski <jarkao2@gmail.com>]

On Thu, Jul 02, 2009 at 07:43:25AM +0200, Paweł Staszewski wrote:
> Jarek Poplawski pisze:
>> On Thu, Jul 02, 2009 at 12:17:19AM +0200, Paweł Staszewski wrote:
>>   
>>> Jarek Poplawski pisze:
>>>     
>> ...
>>   
>>>> So, after your findings I'm about to recommend sending to -stable
>>>> 3 patches from net-2.6, with additional lowering of threshold_root
>>>> settings, but it would be nice if you could give it a try with
>>>> CONFIG_PREEMPT instead of CONFIG_PREEMPT_NONE (if it doesn't break
>>>> your other apps!) It is expected to work this time...;-) Maybe a
>>>> bit slower.
>>>>
>>>>         
>>> Patch applied to 2.6.29.5 with CONFIG_PREEMPT_NONE
>>> And working :)
>>>     
>>
>> Hmm... It should, because you tested very similar patch already;-)
>> Sorry if I didn't make it clear.
>>
>>   
> Yes i know there was almost identical one.
> And i see this was without sync rcu :)

Yes, it looks like we can't free memory so simple because of such huge
latencies.  

>
>>> fib_triestats in attached file
>>>
>>> I think I can test it with PREEMPT enabled but first i must make some 
>>>  other tests of my apps that are on server.
>>>     
>>
>> It could probably matter only if you're using some broken out-of-tree
>> patches. Otherwise the kernel is expected to work OK.
>>
>>   
> Im a little confused about using of PREEMPT kernel because of past
> there was many oopses / lockups :) but yes that was a little long time ago.
> I will try to make this test today.
>
>> Btw., it would be also interesting to check if there is any difference
>> wrt. these route cache problems while PREEMPT is enabled.

And you're very right! The place we're fixing is the best example. On
the other hand, I hope there is not many such places yet. But if we
test/fix it there will be one less...

Jarek P.