lkml.org 
[lkml]   [2015]   [Feb]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/2] [PATCH] sched: Add smp_rmb() in task rq locking cycles
On Wed, Feb 18, 2015 at 05:32:56PM +0100, Oleg Nesterov wrote:
> On 02/18, Peter Zijlstra wrote:
> >
> > On Wed, Feb 18, 2015 at 04:53:34PM +0100, Oleg Nesterov wrote:
> > > On 02/17, Paul E. McKenney wrote:
> > > >
> > > > | mb | wmb | rmb | rbd | acq | rel | ctl |
> > > > -----+-------+-------+-------+-------+-------+-------+-------+
> > > > mb | Y | | Y | y | Y | | Y +
> > > > -----+-------+-------+-------+-------+-------+-------+-------+
> > > > wmb | Y | | Y | y | Y | | Y +
> > > > -----+-------+-------+-------+-------+-------+-------+-------+
> > > > rmb | | | | | | | +
> > > > -----+-------+-------+-------+-------+-------+-------+-------+
> > > > rbd | | | | | | | +
> > > > -----+-------+-------+-------+-------+-------+-------+-------+
> > > > acq | | | | | | | +
> > > > -----+-------+-------+-------+-------+-------+-------+-------+
> > > > rel | Y | | Y | y | Y | | Y +
> > > > -----+-------+-------+-------+-------+-------+-------+-------+
> > > > ctl | | | | | | | +
> > > > -----+-------+-------+-------+-------+-------+-------+-------+
> > >
> > > OK, so "acq" can't pair with "acq", and I am not sure I understand.
> >
> > Please consider the table in the context of message passing; that is
> > what Paul proposed. Your example from sysvsems, while interesting, would
> > not fit the general scenario of message passing.
>
> Ah, yeeees, sorry. Somehow I completely missed that part of Paul's email.
>
> > This too illustrates a problem with that approach, people can't read, so
> > they'll pick the wrong table to look at.
>
> At least we know that I certainly can't ;)

Nobody can! ;-)

Thanx, Paul



\
 
 \ /
  Last update: 2015-02-18 20:41    [W:0.157 / U:0.044 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site