Re: VM working much better in 2.4.8 than before

[Daniel Phillips]

On August 13, 2001 05:52 pm, Rik van Riel wrote:
> On Mon, 13 Aug 2001, Alan Cox wrote:
> > > Yes, those would be the expected effects of use-once, in fact it was
> > > "morning after updatedb" question that got me started on it.
> >
> > updatedb is also absolutely fine if you just work with the existing VM
> > and up the inode pressure a little. I'm still very unconvinced by
> > use-once.
> 
> Use-once has a number of theoretical disadvantages too:
> 
> 1) newly read in pages are evicted earlier, this means
>    readahead pages will either evict each other or the
>    amount of readahead done might need to be shrunk
>    -- the current readahead code is not prepared for this,
>       use-once could lead to more disk seeks being done

Have you actually seen this happening?
 
> 2) since we add new pages to the inactive list, VM
>    balancing is faced with a really strange situation ;)
> 
> Yes, these things are solvable, but not without redesigning
> major parts of the VM balancing to do things which have never
> been done before. I'm not sure 2.4 is the time to do that.

--
Daniel