Re: [RFC PATCH] introduce sys_membarrier(): process-wide memory barrier (v5)

Mathieu Desnoyers
2010-01-13T19:17:32Z

* Nicholas Miell (nmiell@comcast.net) wrote:
> On Wed, 2010-01-13 at 13:24 -0500, Mathieu Desnoyers wrote:
> > * Nicholas Miell (nmiell@comcast.net) wrote:
> >
> > > The whole point of compat and incompat flags is that it allows new
> > > applications to run on old kernels and either work or fail as
> > > appropriate, depending on whether the new features they're using must be
> > > implemented or can be silently ignored.
> >
> > I see. Thanks for the explanation. Then the expedited flag should
> > clearly be part of the mandatory flags.
> >
> > Can you point me to other system calls that are doing this ?
> >
> > Thanks,
> >
> > Mathieu
>
> Not off the top of my head, but I did steal the idea from the ext2/3/4
> disk format.

Sounds a bit over-engineered to me for system calls, but who knows if we
eventually have to extend sys_membarrier(). This involves that, right
now, I'd have to add a header to include/linux to define these flags.
Also, "int expedited" is a bit clearer, but less flexible, than "int
flags". Anyone else have comments about this ?

Thanks,

Mathieu

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Mathieu Desnoyers
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