lkml.org 
[lkml]   [2008]   [Feb]   [8]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [git pull] more SLUB updates for 2.6.25
    Nick Piggin a écrit :
    > On Friday 08 February 2008 13:13, Christoph Lameter wrote:
    >> are available in the git repository at:
    >>
    >> git://git.kernel.org/pub/scm/linux/kernel/git/christoph/vm.git slub-linus
    >>
    >> (includes the cmpxchg_local fastpath since the cmpxchg_local work
    >> by Matheiu is in now, and the non atomic unlock by Nick. Verified that
    >> this is not doing any harm after some other patches had been removed.
    >
    > Ah, good. I think it is always a good thing to be able to remove atomics.
    > They place quite a bit of burden on the CPU, especially x86 where it also
    > has implicit memory ordering semantics (although x86 can speculatively
    > get around much of the problem, it's obviously worse than no restriction)
    >
    > Even if perhaps some cache coherency or timing quirk makes the non-atomic
    > version slower (all else being equal), then I'd still say that the non
    > atomic version should be preferred.
    >

    What about IRQ masking then ?

    Many CPU pay high cost for cli/sti pair...

    And SLAB/SLUB allocators, even if only used from process context, want to
    disable/re-enable interrupts...

    I understand kmalloc() want generic pools, but dedicated pools could avoid
    this cli/sti

    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2008-02-08 08:33    [W:3.008 / U:0.056 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site