Messages in this thread | | | Date | Wed, 23 Oct 2002 04:05:34 +0200 | From | Andrea Arcangeli <> | Subject | Re: [patch] generic nonlinear mappings, 2.5.44-mm2-D0 |
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On Tue, Oct 22, 2002 at 10:19:37PM +0200, Ingo Molnar wrote: > protection bits. It has been clearly established in the past few years > empirically that the vma tree approach itself sucks performance-wise for > applications that have many different mappings.
if you're talking about get_unmapped_area showing up heavy on the profiling then you're on the wrong track with this, if nobody beats me I will fix that one soon right, I discussed that some month ago with Claus Fisher and it's going to be optimized away completely from all profilings out there (at least as much as mmap). The vma ram overhead will be still there though, just the cpu overhead will go away, but I never heard anybody complaining about finishing ram because of vmas yet (while I know several cases where the lack of O(log(N)) in get_unmapped_area is a showstopper, the GUI as well suffers badly with the hundred of librarians but the guis are otherwise idle so it doesn't matter much for them if the cpu is wasted but they will get a bit lower latency).
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