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

From: Mathieu Desnoyers
Date: Wed Jan 13 2010 - 14:17:37 EST


* Nicholas Miell (nmiell@xxxxxxxxxxx) wrote:
> On Wed, 2010-01-13 at 13:24 -0500, Mathieu Desnoyers wrote:
> > * Nicholas Miell (nmiell@xxxxxxxxxxx) 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

--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/