[lkml]   [2008]   [Apr]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: Does process need to have a kernel-side stack all the time?
    On Monday 14 April 2008 19:44, Andi Kleen wrote:
    > > A lot of effort went into minimizing of stack usage.
    > > If I understand it correctly, one of the reasons for this
    > > was to be efficient and not have lots of pages
    > > used for stacks when we have a lot of threads
    > > (tens of thousands).
    > Actually the real reason the 4K stacks were introduced IIRC was that
    > the VM is not very good at allocation of order > 0 pages and that only
    > using order 0 and not order 1 in normal operation prevented some stalls.
    > This rationale also goes back to 2.4 (especially some of the early 2.4
    > VMs were not very good) and the 2.6 VM is generally better and on
    > x86-64 I don't see much evidence that these stalls are a big problem
    > (but then x86-64 also has more lowmem).
    > Note that your proposal doesn't change this at all.

    Actually, it does, because if you have only N*no_of_CPUs stacks,
    you can allocate them upfront, making fragmentation a non-issue.

    However, the proposal doesn't look viable anyway.

     \ /
      Last update: 2008-04-14 20:49    [W:0.025 / U:1.008 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site