Messages in this thread | | | Date | Fri, 4 Jan 2002 15:24:09 +0100 | From | Stephan von Krawczynski <> | Subject | Re: [2.4.17/18pre] VM and swap - it's really unusable |
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On Fri, 4 Jan 2002 15:14:38 +0100 Andrea Arcangeli <andrea@suse.de> wrote:
> On Fri, Jan 04, 2002 at 01:33:21PM +0100, Stephan von Krawczynski wrote: > > On Thu, 03 Jan 2002 20:14:42 -0600 > > "M.H.VanLeeuwen" <vanl@megsinet.net> wrote: > > > > And there is another difference here: > > > > + if (max_mapped <= 0 && nr_pages > 0) > > + swap_out(priority, gfp_mask, classzone); > > + > > > > It sounds reasonable _not_ to swap in case of success (nr_pages == 0). > > To me this looks pretty interesting. Is something like this already in -aa? > > This patch may be worth applying in 2.4. It is small and looks like the right> > thing to do. > > -aa swapout as soon as max_mapped hits zero. So it basically does it > internally (i.e. way more times) and so it will most certainly be able > to sustain an higher swap transfer rate. You can check with the mtest01 > -w test from ltp.
Hm, but do you think this is really good in overall performance, especially the frequent cases where no swap should be needed _at all_ to do a successful shrinking? And - as can be viewed in Martins tests - if you have no swap at all, you seem to trigger OOM earlier through the short path exit in shrink, which is a obvious nono. I would state it wrong to fix the oom-killer for this case, because it should not be reached at all.
?
Regards, Stephan
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