Messages in this thread | | | Date | Wed, 21 Feb 2018 09:34:57 +0100 (CET) | From | Thomas Gleixner <> | Subject | Re: [RFC PATCH V2 13/22] x86/intel_rdt: Support schemata write - pseudo-locking core |
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On Tue, 20 Feb 2018, Mike Kravetz wrote: > On 02/20/2018 03:21 PM, Thomas Gleixner wrote: > > The other problem is that we'd need to have MAP_CONTIG first so you > > actually can allocate physically contigous memory from user space. Mike is > > working on that, but it's not available today. The only way to do so today > > (with lots of waste) would be MAP_HUGETLB, which might be an acceptable > > constraint up to the point where MAP_CONTIG is available. > > Just to clarify, there is not any activity on exposing a general purpose > MAP_CONTIG interface to user space. When initially proposed, MAP_CONTIG > was shot down and the suggestion was to create a new in kernel interface > to make allocation of contiguous pages easier. The initial use case was > a driver which could use the new internal interface as part of it's > mmap() routine to give contiguous regions to user space.
Thanks for the clarification.
> Reinette is using this new interface, but that must be for the ?immediate > allocation? case you are trying to move away from. Sorry, I have not been > following development of this feature. > > If you would have to create a device to accept a user buffer, could you > perhaps use the same device to create/hand out a contiguous mapping?
Yes, that's straight forward.
Thanks,
tglx
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