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    SubjectRe: [PATCH] memcg: remove unneeded preempt_disable
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    Christoph Lameter <cl@linux.com> wrote:

    >On Thu, 25 Aug 2011, James Bottomley wrote:
    >
    >> >ARM seems to have these LDREX/STREX instructions for that purpose
    >which
    >> >seem to be used for generating atomic instructions without lockes. I
    >> >guess
    >> >other RISC architectures have similar means of doing it?
    >>
    >> Arm isn't really risc. Most don't. However even with ldrex/strex
    >you need two instructions for rmw.
    >
    >Well then what is "really risc"? RISC is an old beaten down marketing
    >term
    >AFAICT and ARM claims it too.

    Reduced Instruction Set Computer. This is why we're unlikely to have complex atomic instructions: the principle of risc is that you build them up from basic ones.

    James
    --
    Sent from my Android phone with K-9 Mail. Please excuse my brevity and top posting.


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