Re: [PATCH] Optimize out pte_chain take three

Rik van Riel
2002-07-11T20:54:22Z

On Thu, 11 Jul 2002, Andrew Morton wrote:
> Rik van Riel wrote:
> > ...
> > > useful pagecache and swapping everything out. Our kernels have
> > > O_STREAMING because of this. It simply removes as much pagecache
> > > as it can, each time ->nrpages reaches 256. It's rather effective.
> >
> > Now why does that remind me of drop-behind ? ;)
>
> I looked at 2.4-ac as well. Seems that the dropbehind there only
> addresses reads?

It should also work on linear writes.

> I suspect the best fix here is to not have dirty or writeback
> pagecache pages on the LRU at all. Throttle on memory coming
> reclaimable, put the pages back on the LRU when they're clean,
> etc. As we have often discussed. Big change.

That just doesn't make sense, if you don't put the dirty pages
on the LRU then what incentive _do_ you have to write them out ?

Will you start writing them out once you run out of clean pages ?

Will you reclaim all glibc mapped pages before writing out dirty
pages ?

If the throttling is wrong, I propose we fix the trottling.

regards,

Rik
--
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