Re: VM patches in 2.6.4-rc1-mm2

[Nick Piggin <piggin@cyberone.com.au>]

Mike Fedyk wrote:

> Nick Piggin wrote:
>
>>
>>
>> Mike Fedyk wrote:
>>
>>> Nick Piggin wrote:
>>>
>>>> Mainline doesn't put enough pressure on slab with highmem systems. 
>>>> This
>>>> creates a lot more ZONE_NORMAL pressure and that causes swapping.
>>>>
>>>
>>> Yep, saw that.  Especially with 128MB Highmem (eg, 1G RAM)
>>>
>>>> Now with the 2.6 VM, you don't do any mapped memory scaning at all
>>>
>>>
>>>
>>>
>>> You mean 2.6-mm?
>>>
>>
>> Yes, either mm or linus.
>>
>
> Have there been any VM patches merged into mainline?  Or are you 
> saying that the imbalance in mainline would be enough to overcome to 
> lack of scanning of mapped pages?
>

There have been no VM patches merged into mainline. I just mean that
neither mm or mainline does any mapped memory scanning when memory
pressure is low.

>>
>> If you get a lot of pressure at one time it should push out your
>> inactive mapped pages. Will get most of the really inactive ones,
>> but it won't help pages becoming inactive in future.
>>
>
> Ok, I see.  This might be happening, since it is steadily getting more 
> into swap.
>


For the one that is swapping, yes this would be happening.


>>
>> Hasn't looked at it much. Probably not until some of the more basic
>> VM patches can get merged into -linus.
>
>
> Yes, I wonder if the VM patches helped -mm in the reaim tests...
>
> Let's get the fsfaz (free slab for all zones) into mainline asap! :-D
>


Well all the ones in -mm now are probably right to go to 2.6.5
I hope.