Messages in this thread | | | Date | Tue, 26 Feb 2008 06:28:50 -0600 | From | Robin Holt <> | Subject | Re: [ofa-general] Re: [patch 5/6] mmu_notifier: Support for drivers with revers maps (f.e. for XPmem) |
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On Tue, Feb 26, 2008 at 07:52:41PM +1100, Nick Piggin wrote: > On Tuesday 26 February 2008 18:21, Gleb Natapov wrote: > > On Tue, Feb 26, 2008 at 05:11:32PM +1100, Nick Piggin wrote: > > > > You are missing one point here. The MPI specifications that have > > > > been out there for decades do not require the process use a library > > > > for allocating the buffer. I realize that is a horrible shortcoming, > > > > but that is the world we live in. Even if we could change that spec, > > > > > > Can you change the spec? > > > > Not really. It will break all existing codes. > > I meant as in eg. submit changes to MPI-3 > > > > MPI-2 provides a call for > > memory allocation (and it's beneficial to use this call for some > > interconnects), but many (most?) applications are still written for MPI-1 > > and those that are written for MPI-2 mostly uses the old habit of > > allocating memory by malloc(), or even use stack or BSS memory for > > communication buffer purposes. > > OK, so MPI-2 already has some way to do that... I'm not saying that we > can now completely dismiss the idea of using notifiers for this, but it > is just a good data point to know.
It is in MPI-2, but MPI-2 does not prohibit communication from regions not allocated by the MPI call.
Thanks, Robin
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