Re: Large slab cache in 2.6.1

Ed Tomlinson
2004-02-23T03:33:25Z

On February 22, 2004 09:28 pm, Mike Fedyk wrote:
> Ed Tomlinson wrote:
> > On February 21, 2004 10:28 pm, Linus Torvalds wrote:
> >>On Sat, 21 Feb 2004, Chris Wedgwood wrote:
> >>>Maybe gradual page-cache pressure could shirnk the slab?
> >>
> >>What happened to the experiment of having slab pages on the (in)active
> >>lists and letting them be free'd that way? Didn't somebody already do
> >>that? Ed Tomlinson and Craig Kulesa?
> >
> > You have a good memory.
> >
> > We dropped this experiment since there was a lot of latency between the
> > time a slab page became freeable and when it was actually freed. The
> > current call back scheme was designed to balance slab preasure and
> > vmscaning.
>
> Does it really matter if there is a lot of latency? How does this
> affect real-world results? IOW, if it's not at the end of the LRU, then
> there's probably something better to free instead...

It mattered. People noticed and complained. In any case, as Andrew
pointed out, we get the same effect, without long latencies, in a simplier
manner with the current scheme.

Ed