Re: ~500 megs cached yet 2.6.5 goes into swap hell

Nick Piggin
2004-04-30T06:34:59Z

Tim Connors wrote:
> Horst von Brand <vonbrand@inf.utfsm.cl> said on Thu, 29 Apr 2004 16:01:11 -0400:
>
>>Nick Piggin <nickpiggin@yahoo.com.au> said:
>>
>>[...]
>>
>>
>>>I don't know. What if you have some huge application that only
>>>runs once per day for 10 minutes? Do you want it to be consuming
>>>100MB of your memory for the other 23 hours and 50 minutes for
>>>no good reason?
>>
>>How on earth is the kernel supposed to know that for this one particular
>>job you don't care if it takes 3 hours instead of 10 minutes, just because
>>you don't want to spare enough preciousss RAM?
>
>
> Note that we are not talking about having insufficient memory. In my
> case (2.4 kernel - ie, 2.6 with swapiness 0%) there is more than
> enough memory to contain all my working set - it's only because cache
> is too eager to claim memory that is otherwise in use that
> non-optimalities occur.
>

Well depends on what you mean by working set.

In our memory manager, there is a point where often used
"file cache" (ie. unmapped cache) is considered preferable
to unused or little used "application memory" (mapped
memory).

There will be a point where even the most swap phobic desktop
users will want to start swapping.

I missed the description of your exact problem... was it in
this thread somewhere? Testing 2.6 would be appreciated if
possible too.