Messages in this thread | | | Date | Tue, 17 Jun 2014 11:28:19 -0500 (CDT) | From | Christoph Lameter <> | Subject | Re: [PATCH RFC] percpu: add data dependency barrier in percpu accessors and operations |
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On Tue, 17 Jun 2014, Tejun Heo wrote:
> On Tue, Jun 17, 2014 at 12:00:40PM -0400, Tejun Heo wrote: > > Hello, Christoph. > > > > On Tue, Jun 17, 2014 at 10:56:10AM -0500, Christoph Lameter wrote: > > > Uhhh no. The percpu stuff and the associated per cpu atomics are to be > > > used for stuff that is per cpu specific and runs at the fastest speed > > > doable at that level. Introducing implicit barriers is not that good an > > > idea. > > > > Hmmm? Read barriers are noops on all archs except for alpha and > > Oops, data dependency barriers, not read barrier.
Even alpha maintains the illusion of changes becoming visible in the proper order for the currently executing thread. No barriers are needed.
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