Messages in this thread | | | Subject | Re: [PATCH V5 1/4] ACPI: Support Generic Initiator only domains | From | Tao Xu <> | Date | Wed, 13 Nov 2019 21:57:24 +0800 |
| |
On 11/13/2019 5:47 PM, Jonathan Cameron wrote: > On Tue, 12 Nov 2019 09:55:17 -0800 > Dan Williams <dan.j.williams@intel.com> wrote: > >> [ add Tao Xu ] >> >> On Fri, Oct 4, 2019 at 4:45 AM Jonathan Cameron >> <Jonathan.Cameron@huawei.com> wrote: >>> >>> Generic Initiators are a new ACPI concept that allows for the >>> description of proximity domains that contain a device which >>> performs memory access (such as a network card) but neither >>> host CPU nor Memory. >>> >>> This patch has the parsing code and provides the infrastructure >>> for an architecture to associate these new domains with their >>> nearest memory processing node. >> >> Thanks for this Jonathan. May I ask how this was tested? Tao has been >> working on qemu support for HMAT [1]. I have not checked if it already >> supports generic initiator entries, but it would be helpful to include >> an example of how the kernel sees these configurations in practice. >> >> [1]: http://patchwork.ozlabs.org/cover/1096737/ > > Tested against qemu with SRAT and SLIT table overrides from an > initrd to actually create the node and give it distances > (those all turn up correctly in the normal places). DSDT override > used to move an emulated network card into the GI numa node. That > currently requires the PCI patch referred to in the cover letter. > On arm64 tested both on qemu and real hardware (overrides on tables > even for real hardware as I can't persuade our BIOS team to implement > Generic Initiators until an OS is actually using them.) > > Main real requirement is memory allocations then occur from one of > the nodes at the minimal distance when you are do a devm_ allocation > from a device assigned. Also need to be able to query the distances > to allow load balancing etc. All that works as expected. > > It only has a fairly tangential connection to HMAT in that HMAT > can provide information on GI nodes. Given HMAT code is quite happy > with memoryless nodes anyway it should work. QEMU doesn't currently > have support to create GI SRAT entries let alone HMAT using them. > > Whilst I could look at adding such support to QEMU, it's not > exactly high priority to emulate something we can test easily > by overriding the tables before the kernel reads them. > > I'll look at how hard it is to build an HMAT tables for my test > configs based on the ones I used to test your HMAT patches a while > back. Should be easy if tedious. > > Jonathan > Indeed, HMAT can support Generic Initiator, but as far as I know, QEMU only can emulate a node with cpu and memory, or memory-only. Even if we assign a node with cpu only, qemu will raise error. Considering compatibility, there are lots of work to do for QEMU if we change NUMA or SRAT table.
| |