Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1629994

Re: Question on the five-level page table support patches

Show all headers | View raw

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

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

Question on the five-level page table support patches John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> - 2017-04-23 13:00 +0200
  Re: Question on the five-level page table support patches Andy Lutomirski <luto@kernel.org> - 2017-04-24 07:20 +0200
    Re: Question on the five-level page table support patches Andi Kleen <ak@linux.intel.com> - 2017-04-24 15:10 +0200
      Re: Question on the five-level page table support patches John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> - 2017-04-24 22:40 +0200
  Re: Question on the five-level page table support patches "Kirill A. Shutemov" <kirill@shutemov.name> - 2017-04-24 18:30 +0200
    Re: Question on the five-level page table support patches John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> - 2017-04-24 22:40 +0200
      Re: Question on the five-level page table support patches "Kirill A. Shutemov" <kirill@shutemov.name> - 2017-04-25 00:10 +0200
      Re: Question on the five-level page table support patches David Miller <davem@davemloft.net> - 2017-04-25 00:20 +0200
        Re: Question on the five-level page table support patches Jon Masters <jcm@jonmasters.org> - 2017-04-25 09:30 +0200

csiph-web