Messages in this thread |  | | | Date | Tue, 24 Feb 2009 16:01:03 -0800 | | From | Andrew Morton <> | | Subject | Re: [PATCH 20/20] Get rid of the concept of hot/cold page freeing |
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On Tue, 24 Feb 2009 11:51:26 +0000 Mel Gorman <mel@csn.ul.ie> wrote: > > > Almost the opposite with steady improvements almost all the way through. > > > > > > With the patch applied, we are still using hot/cold information on the > > > allocation side so I'm somewhat surprised the patch even makes much of a > > > difference. I'd have expected the pages being freed to be mostly hot. > > > > Oh yeah. Back in the ancient days, hot-cold-pages was using separate > > magazines for hot and cold pages. Then Christoph went and mucked with > > it, using a single queue. That might have affected things. > > > > It might have. The impact is that requests for cold pages can get hot pages > if there are not enough cold pages in the queue so readahead could prevent > an active process getting cache hot pages. I don't think that would have > showed up in the microbenchmark though.
We switched to doing non-temporal stores in copy_from_user(), didn't we? That would rub out the benefit which that microbenchmark demonstrated?
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