Hi All, Anyone had a change to take a look at this? Thanks, Jonathan On Tue, 16 Apr 2019 01:49:03 +0800 Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx> wrote: > Changes since RFC V2. > * RFC dropped as now we have x86 support, so the lack of guards in in the > ACPI code etc should now be fine. > * Added x86 support. Note this has only been tested on QEMU as I don't have > a convenient x86 NUMA machine to play with. Note that this fitted together > rather differently form arm64 so I'm particularly interested in feedback > on the two solutions. > > Since RFC V1. > * Fix incorrect interpretation of the ACPI entry noted by Keith Busch > * Use the acpica headers definitions that are now in mmotm. > > It's worth noting that, to safely put a given device in a GI node, may > require changes to the existing drivers as it's not unusual to assume > you have local memory or processor core. There may be futher constraints > not yet covered by this patch. > > Original cover letter... > > ACPI 6.3 introduced a new entity that can be part of a NUMA proximity domain. > It may share such a domain with the existing options (memory, cpu etc) but it > may also exist on it's own. > > The intent is to allow the description of the NUMA properties (particulary > via HMAT) of accelerators and other initiators of memory activity that are not > the host processor running the operating system. > > This patch set introduces 'just enough' to make them work for arm64 and x86. > It should be trivial to support other architectures, I just don't suitable > NUMA systems readily available to test. > > There are a few quirks that need to be considered. > > 1. Fall back nodes > ****************** > > As pre ACPI 6.3 supporting operating systems do not have Generic Initiator > Proximity Domains it is possible to specify, via _PXM in DSDT that another > device is part of such a GI only node. This currently blows up spectacularly. > > Whilst we can obviously 'now' protect against such a situation (see the related > thread on PCI _PXM support and the threadripper board identified there as > also falling into the problem of using non existent nodes > https://patchwork.kernel.org/patch/10723311/ ), there is no way to be sure > we will never have legacy OSes that are not protected against this. It would > also be 'non ideal' to fallback to a default node as there may be a better > (non GI) node to pick if GI nodes aren't available. > > The work around is that we also have a new system wide OSC bit that allows > an operating system to 'annouce' that it supports Generic Initiators. This > allows, the firmware to us DSDT magic to 'move' devices between the nodes > dependent on whether our new nodes are there or not. > > 2. New ways of assigning a proximity domain for devices > ******************************************************* > > Until now, the only way firmware could indicate that a particular device > (outside the 'special' set of cpus etc) was to be found in a particular > Proximity Domain by the use of _PXM in DSDT. > > That is equally valid with GI domains, but we have new options. The SRAT > affinity structure includes a handle (ACPI or PCI) to identify devices > with the system and specify their proximity domain that way. If both _PXM > and this are provided, they should give the same answer. > > For now this patch set completely ignores that feature as we don't need > it to start the discussion. It will form a follow up set at some point > (if no one else fancies doing it). > > Jonathan Cameron (4): > ACPI: Support Generic Initiator only domains > arm64: Support Generic Initiator only domains > x86: Support Generic Initiator only proximity domains > ACPI: Let ACPI know we support Generic Initiator Affinity Structures > > arch/arm64/kernel/smp.c | 8 +++++ > arch/x86/include/asm/numa.h | 2 ++ > arch/x86/kernel/setup.c | 1 + > arch/x86/mm/numa.c | 14 ++++++++ > drivers/acpi/bus.c | 1 + > drivers/acpi/numa.c | 62 +++++++++++++++++++++++++++++++++- > drivers/base/node.c | 3 ++ > include/asm-generic/topology.h | 3 ++ > include/linux/acpi.h | 1 + > include/linux/nodemask.h | 1 + > include/linux/topology.h | 7 ++++ > 11 files changed, 102 insertions(+), 1 deletion(-) >
