Messages in this thread | | | Date | Thu, 28 Jun 2001 16:04:34 +0200 (CEST) | From | Tobias Ringstrom <> | Subject | Re: VM Requirement Document - v0.0 |
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On Thu, 28 Jun 2001, Alan Cox wrote:
> > > That isnt really down to labelling pages, what you are talking qbout is what > > > you get for free when page aging works right (eg 2.0.39) but don't get in > > > 2.2 - and don't yet (although its coming) quite get right in 2.4.6pre. > > > > Correct, but all pages are not equal. > > That is the whole point of page aging done right. The use of a page dictates > how it is aged before being discarded. So pages referenced once are aged > rapidly, but once they get touched a couple of times then you know they arent > streaming I/O. There are other related techniques like punishing pages that > are touched when streaming I/O is done to pages further down the same file - > FreeBSD does this one for example
Are you saying that classification of pages will not be useful?
Only looking at the page access patterns can certainly reveal a lot, but tuning how to punish different pages is useful.
> > The problem with updatedb is that it pushes all applications to the swap, > > and when you get back in the morning, everything has to be paged back from > > swap just because the (stupid) OS is prepared for yet another updatedb > > run. > > Updatedb is a bit odd in that it mostly sucks in metadata and the buffer to > page cache balancing is a bit suspect IMHO.
In 2.4.6-pre, the buffer cache is no longer used for metata, right?
/Tobias
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