lkml.org 
[lkml]   [2010]   [Aug]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [PATCH tip/core/rcu 08/10] rcu: Add a TINY_PREEMPT_RCU
    From
    Date
    On Tue, 2010-08-17 at 11:55 -0400, Mathieu Desnoyers wrote:

    > > Heck, this is too much micro optimization. We could just be safe and do
    > > the:
    > > --t->rcu_read_lock_nesting;
    > > barrier();
    > > if (ACCESS_ONCE(t->rcu_read_lock_nesting) == 0 &&
    > > unlikely((ACCESS_ONCE(t->rcu_read_unlock_special)))
    > >
    > > And be done with it.
    >
    > Then we could go for the simpler:
    >
    > --t->rcu_read_lock_nesting;
    > barrier();
    > if (t->rcu_read_lock_nesting == 0 &&
    > unlikely((t->rcu_read_unlock_special))

    Yeah, that's what I meant, I was too lazy to remove the ACCESS_ONCE()
    from the cut and paste I did.

    >
    > Which puts a constraint across all memory accesses. I'd be fine with
    > that if you are afraid of too much micro-optimization (e.g. my
    > barrier2(a, b) proposal).

    Not afraid, but just too much code for a simple solution.

    -- Steve




    \
     
     \ /
      Last update: 2010-08-17 18:07    [W:0.034 / U:0.220 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site