Messages in this thread |  | | Date | Wed, 20 Feb 2008 03:00:36 -0600 | | From | Robin Holt <> | | Subject | Re: [patch 5/6] mmu_notifier: Support for drivers with revers maps (f.e. for XPmem) |
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On Wed, Feb 20, 2008 at 02:51:45PM +1100, Nick Piggin wrote: > On Wednesday 20 February 2008 14:12, Robin Holt wrote: > > For XPMEM, we do not currently allow file backed > > mapping pages from being exported so we should never reach this condition. > > It has been an issue since day 1. We have operated with that assumption > > for 6 years and have not had issues with that assumption. The user of > > xpmem is MPT and it controls the communication buffers so it is reasonable > > to expect this type of behavior. > > OK, that makes things simpler. > > So why can't you export a device from your xpmem driver, which > can be mmap()ed to give out "anonymous" memory pages to be used > for these communication buffers?
Because we need to have heap and stack available as well. MPT does not control all the communication buffer areas. I haven't checked, but this is the same problem that IB will have. I believe they are actually allowing any memory region be accessible, but I am not sure of that.
Thanks, Robin
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