Messages in this thread | | | From | Daniel Phillips <> | Subject | Re: 2.4.8/2.4.9 VM problems | Date | Tue, 21 Aug 2001 00:54:32 +0200 |
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On August 20, 2001 10:16 pm, Marcelo Tosatti wrote: > On Mon, 20 Aug 2001, Marcelo Tosatti wrote: > > On Mon, 20 Aug 2001, Daniel Phillips wrote: > > > On Mon, 20 Aug 2001, Marcelo Tosatti wrote: > > > > Find riel's message with topic "VM tuning" to linux-mm, then take a look > > > > at the 4th aging option. > > > > > > > > That one _should_ be able to make us remove all kinds of "hacks" to do > > > > drop behind, and also it should keep hot/warm active memory _in cache_ > > > > for more time. > > > > > > I looked at it yesterday. The problem is, it loses the information about *how* > > > a page is used: pagecache lookup via readahead has different implications than > > > actual usage. > > And ah, I forgot something here. > > Your statement which says "pagecache lookup via readahead has different > implications than actual usage" is not really correct. > > If you only consider "hot" pages as "pages which have been touched", > you're going to (potentially) fuck heavy streaming IO workloads.
"Hot" pages are pages that have been touched more than once. The idea of use-once (on the read side) is to retain the readahead pages just long enough to use them, and not a lot longer. If you've seen streaming IO pages getting evicted before being used, I'd like to know about it because something is broken in that case.
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