Messages in this thread | | | Subject | Re: Question on the five-level page table support patches | From | John Paul Adrian Glaubitz <> | Date | Mon, 24 Apr 2017 22:33:22 +0200 |
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On 04/24/2017 03:03 PM, Andi Kleen wrote: > In old Linux hint was a search hint, so if there isn't a hole > at the hinted area it will search starting from there for a hole > instead of giving up immediately.
Yep, that's what I meant. It used to work like that and it still works like that on NetBSD, for example. Although it has apparently been a long time since it changed [1].
> Now it just gives up, which means every user has to implement > their own search.
Correct. And the resulting code is usually ugly and inefficient [2].
> Yes I ran into the same problem and it's annoying. It broke > originally when top down mmap was added I believe > > Before the augmented rbtree it was potentially very expensive, but now > it should be cheap.
I'm not sure whether I understand what that means.
Thanks, Adrian
> [1] http://lkml.iu.edu/hypermail/linux/kernel/0305.2/0828.html > [2] https://hg.mozilla.org/mozilla-central/rev/dfaafbaaa291
-- .''`. John Paul Adrian Glaubitz : :' : Debian Developer - glaubitz@debian.org `. `' Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de `- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913
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