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* [PATCH 0/4 V3] ACPI: Support generic initiator proximity domains
@ 2019-04-15 17:49 Jonathan Cameron
  2019-04-15 17:49 ` [PATCH 1/4 V3] ACPI: Support Generic Initiator only domains Jonathan Cameron
                   ` (4 more replies)
  0 siblings, 5 replies; 7+ messages in thread
From: Jonathan Cameron @ 2019-04-15 17:49 UTC (permalink / raw)
  To: linux-mm, linux-acpi, linux-kernel, linux-arm-kernel
  Cc: Jérôme Glisse, Keith Busch, Rafael J . Wysocki,
	linuxarm, Andrew Morton, Jonathan Cameron

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(-)

-- 
2.19.1


^ permalink raw reply	[flat|nested] 7+ messages in thread

* [PATCH 1/4 V3] ACPI: Support Generic Initiator only domains
  2019-04-15 17:49 [PATCH 0/4 V3] ACPI: Support generic initiator proximity domains Jonathan Cameron
@ 2019-04-15 17:49 ` Jonathan Cameron
  2019-04-15 17:49 ` [PATCH 2/4 V3] arm64: " Jonathan Cameron
                   ` (3 subsequent siblings)
  4 siblings, 0 replies; 7+ messages in thread
From: Jonathan Cameron @ 2019-04-15 17:49 UTC (permalink / raw)
  To: linux-mm, linux-acpi, linux-kernel, linux-arm-kernel
  Cc: Jérôme Glisse, Keith Busch, Rafael J . Wysocki,
	linuxarm, Andrew Morton, Jonathan Cameron

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.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/acpi/numa.c            | 62 +++++++++++++++++++++++++++++++++-
 drivers/base/node.c            |  3 ++
 include/asm-generic/topology.h |  3 ++
 include/linux/nodemask.h       |  1 +
 include/linux/topology.h       |  7 ++++
 5 files changed, 75 insertions(+), 1 deletion(-)

diff --git a/drivers/acpi/numa.c b/drivers/acpi/numa.c
index 867f6e3f2b4f..b08ceea5e546 100644
--- a/drivers/acpi/numa.c
+++ b/drivers/acpi/numa.c
@@ -184,6 +184,38 @@ acpi_table_print_srat_entry(struct acpi_subtable_header *header)
 		}
 		break;
 
+	case ACPI_SRAT_TYPE_GENERIC_AFFINITY:
+	{
+		struct acpi_srat_generic_affinity *p =
+			(struct acpi_srat_generic_affinity *)header;
+		char name[9] = {};
+
+		if (p->device_handle_type == 0) {
+			/*
+			 * For pci devices this may be the only place they
+			 * are assigned a proximity domain
+			 */
+			pr_debug("SRAT Generic Initiator(Seg:%u BDF:%u) in proximity domain %d %s\n",
+				 *(u16 *)(&p->device_handle[0]),
+				 *(u16 *)(&p->device_handle[2]),
+				 p->proximity_domain,
+				 (p->flags & ACPI_SRAT_GENERIC_AFFINITY_ENABLED) ?
+				"enabled" : "disabled");
+		} else {
+			/*
+			 * In this case we can rely on the device having a
+			 * proximity domain reference
+			 */
+			memcpy(name, p->device_handle, 8);
+			pr_info("SRAT Generic Initiator(HID=%.8s UID=%.4s) in proximity domain %d %s\n",
+				(char *)(&p->device_handle[0]),
+				(char *)(&p->device_handle[8]),
+				p->proximity_domain,
+				(p->flags & ACPI_SRAT_GENERIC_AFFINITY_ENABLED) ?
+				"enabled" : "disabled");
+		}
+	}
+	break;
 	default:
 		pr_warn("Found unsupported SRAT entry (type = 0x%x)\n",
 			header->type);
@@ -392,6 +424,32 @@ acpi_parse_gicc_affinity(struct acpi_subtable_header *header,
 	return 0;
 }
 
+static int __init
+acpi_parse_gi_affinity(struct acpi_subtable_header *header,
+		       const unsigned long end)
+{
+	struct acpi_srat_generic_affinity *gi_affinity;
+	int node;
+
+	gi_affinity = (struct acpi_srat_generic_affinity *)header;
+	if (!gi_affinity)
+		return -EINVAL;
+	acpi_table_print_srat_entry(header);
+
+	if (!(gi_affinity->flags & ACPI_SRAT_GENERIC_AFFINITY_ENABLED))
+		return -EINVAL;
+
+	node = acpi_map_pxm_to_node(gi_affinity->proximity_domain);
+	if (node == NUMA_NO_NODE || node >= MAX_NUMNODES) {
+		pr_err("SRAT: Too many proximity domains.\n");
+		return -EINVAL;
+	}
+	node_set(node, numa_nodes_parsed);
+	node_set_state(node, N_GENERIC_INITIATOR);
+
+	return 0;
+}
+
 static int __initdata parsed_numa_memblks;
 
 static int __init
@@ -447,7 +505,7 @@ int __init acpi_numa_init(void)
 
 	/* SRAT: System Resource Affinity Table */
 	if (!acpi_table_parse(ACPI_SIG_SRAT, acpi_parse_srat)) {
-		struct acpi_subtable_proc srat_proc[3];
+		struct acpi_subtable_proc srat_proc[4];
 
 		memset(srat_proc, 0, sizeof(srat_proc));
 		srat_proc[0].id = ACPI_SRAT_TYPE_CPU_AFFINITY;
@@ -456,6 +514,8 @@ int __init acpi_numa_init(void)
 		srat_proc[1].handler = acpi_parse_x2apic_affinity;
 		srat_proc[2].id = ACPI_SRAT_TYPE_GICC_AFFINITY;
 		srat_proc[2].handler = acpi_parse_gicc_affinity;
+		srat_proc[3].id = ACPI_SRAT_TYPE_GENERIC_AFFINITY;
+		srat_proc[3].handler = acpi_parse_gi_affinity;
 
 		acpi_table_parse_entries_array(ACPI_SIG_SRAT,
 					sizeof(struct acpi_table_srat),
diff --git a/drivers/base/node.c b/drivers/base/node.c
index 86d6cd92ce3d..f59b9d4ca5d5 100644
--- a/drivers/base/node.c
+++ b/drivers/base/node.c
@@ -634,6 +634,8 @@ static struct node_attr node_state_attr[] = {
 #endif
 	[N_MEMORY] = _NODE_ATTR(has_memory, N_MEMORY),
 	[N_CPU] = _NODE_ATTR(has_cpu, N_CPU),
+	[N_GENERIC_INITIATOR] = _NODE_ATTR(has_generic_initiator,
+					   N_GENERIC_INITIATOR),
 };
 
 static struct attribute *node_state_attrs[] = {
@@ -645,6 +647,7 @@ static struct attribute *node_state_attrs[] = {
 #endif
 	&node_state_attr[N_MEMORY].attr.attr,
 	&node_state_attr[N_CPU].attr.attr,
+	&node_state_attr[N_GENERIC_INITIATOR].attr.attr,
 	NULL
 };
 
diff --git a/include/asm-generic/topology.h b/include/asm-generic/topology.h
index 238873739550..54d0b4176a45 100644
--- a/include/asm-generic/topology.h
+++ b/include/asm-generic/topology.h
@@ -71,6 +71,9 @@
 #ifndef set_cpu_numa_mem
 #define set_cpu_numa_mem(cpu, node)
 #endif
+#ifndef set_gi_numa_mem
+#define set_gi_numa_mem(gi, node)
+#endif
 
 #endif	/* !CONFIG_NUMA || !CONFIG_HAVE_MEMORYLESS_NODES */
 
diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h
index 27e7fa36f707..1aebf766fb52 100644
--- a/include/linux/nodemask.h
+++ b/include/linux/nodemask.h
@@ -399,6 +399,7 @@ enum node_states {
 #endif
 	N_MEMORY,		/* The node has memory(regular, high, movable) */
 	N_CPU,		/* The node has one or more cpus */
+	N_GENERIC_INITIATOR,	/* The node is a GI only node */
 	NR_NODE_STATES
 };
 
diff --git a/include/linux/topology.h b/include/linux/topology.h
index cb0775e1ee4b..9d5f8501efcf 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -125,6 +125,13 @@ static inline void set_numa_mem(int node)
 }
 #endif
 
+#ifndef set_gi_numa_mem
+static inline void set_gi_numa_mem(int gi, int node)
+{
+	_node_numa_mem_[gi] = node;
+}
+#endif
+
 #ifndef node_to_mem_node
 static inline int node_to_mem_node(int node)
 {
-- 
2.19.1


^ permalink raw reply	[flat|nested] 7+ messages in thread

* [PATCH 2/4 V3] arm64: Support Generic Initiator only domains
  2019-04-15 17:49 [PATCH 0/4 V3] ACPI: Support generic initiator proximity domains Jonathan Cameron
  2019-04-15 17:49 ` [PATCH 1/4 V3] ACPI: Support Generic Initiator only domains Jonathan Cameron
@ 2019-04-15 17:49 ` Jonathan Cameron
  2019-04-15 17:49 ` [PATCH 3/4 V3] x86: Support Generic Initiator only proximity domains Jonathan Cameron
                   ` (2 subsequent siblings)
  4 siblings, 0 replies; 7+ messages in thread
From: Jonathan Cameron @ 2019-04-15 17:49 UTC (permalink / raw)
  To: linux-mm, linux-acpi, linux-kernel, linux-arm-kernel
  Cc: Jérôme Glisse, Keith Busch, Rafael J . Wysocki,
	linuxarm, Andrew Morton, Jonathan Cameron

The one thing that currently needs doing from an architecture
point of view is associating the GI domain with its nearest
memory domain.  This allows all the standard NUMA aware code
to get a 'reasonable' answer.

A clever driver might elect to do load balancing etc
if there are multiple host / memory domains nearby, but
that's a decision for the driver.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 arch/arm64/kernel/smp.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
index 824de7038967..7c419bf92374 100644
--- a/arch/arm64/kernel/smp.c
+++ b/arch/arm64/kernel/smp.c
@@ -731,6 +731,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 {
 	int err;
 	unsigned int cpu;
+	unsigned int node;
 	unsigned int this_cpu;
 
 	init_cpu_topology();
@@ -769,6 +770,13 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 		set_cpu_present(cpu, true);
 		numa_store_cpu_info(cpu);
 	}
+
+	/*
+	 * Walk the numa domains and set the node to numa memory reference
+	 * for any that are Generic Initiator Only.
+	 */
+	for_each_node_state(node, N_GENERIC_INITIATOR)
+		set_gi_numa_mem(node, local_memory_node(node));
 }
 
 void (*__smp_cross_call)(const struct cpumask *, unsigned int);
-- 
2.19.1


^ permalink raw reply	[flat|nested] 7+ messages in thread

* [PATCH 3/4 V3] x86: Support Generic Initiator only proximity domains
  2019-04-15 17:49 [PATCH 0/4 V3] ACPI: Support generic initiator proximity domains Jonathan Cameron
  2019-04-15 17:49 ` [PATCH 1/4 V3] ACPI: Support Generic Initiator only domains Jonathan Cameron
  2019-04-15 17:49 ` [PATCH 2/4 V3] arm64: " Jonathan Cameron
@ 2019-04-15 17:49 ` Jonathan Cameron
  2019-04-15 17:49 ` [PATCH 4/4 V3] ACPI: Let ACPI know we support Generic Initiator Affinity Structures Jonathan Cameron
  2019-05-28 11:31 ` [PATCH 0/4 V3] ACPI: Support generic initiator proximity domains Jonathan Cameron
  4 siblings, 0 replies; 7+ messages in thread
From: Jonathan Cameron @ 2019-04-15 17:49 UTC (permalink / raw)
  To: linux-mm, linux-acpi, linux-kernel, linux-arm-kernel
  Cc: Jérôme Glisse, Keith Busch, Rafael J . Wysocki,
	linuxarm, Andrew Morton, Jonathan Cameron

Done in a somewhat different fashion to arm64.
Here the infrastructure for memoryless domains was already
in place.  That infrastruture applies just as well to
domains that also don't have a CPU, hence it works for
Generic Initiator Domains.

In common with memoryless domains we only register GI domains
if the proximity node is not online. If a domain is already
a memory containing domain, or a memoryless domain there is
nothing to do just because it also contains a Generic Initiator.

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 arch/x86/include/asm/numa.h |  2 ++
 arch/x86/kernel/setup.c     |  1 +
 arch/x86/mm/numa.c          | 14 ++++++++++++++
 3 files changed, 17 insertions(+)

diff --git a/arch/x86/include/asm/numa.h b/arch/x86/include/asm/numa.h
index bbfde3d2662f..f631467272a3 100644
--- a/arch/x86/include/asm/numa.h
+++ b/arch/x86/include/asm/numa.h
@@ -62,12 +62,14 @@ extern void numa_clear_node(int cpu);
 extern void __init init_cpu_to_node(void);
 extern void numa_add_cpu(int cpu);
 extern void numa_remove_cpu(int cpu);
+extern void init_gi_nodes(void);
 #else	/* CONFIG_NUMA */
 static inline void numa_set_node(int cpu, int node)	{ }
 static inline void numa_clear_node(int cpu)		{ }
 static inline void init_cpu_to_node(void)		{ }
 static inline void numa_add_cpu(int cpu)		{ }
 static inline void numa_remove_cpu(int cpu)		{ }
+static inline void init_gi_nodes(void)			{ }
 #endif	/* CONFIG_NUMA */
 
 #ifdef CONFIG_DEBUG_PER_CPU_MAPS
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index 3d872a527cd9..240568c3ac60 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1245,6 +1245,7 @@ void __init setup_arch(char **cmdline_p)
 	prefill_possible_map();
 
 	init_cpu_to_node();
+	init_gi_nodes();
 
 	io_apic_init_mappings();
 
diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index dfb6c4df639a..5770d2dcad29 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -732,6 +732,20 @@ static void __init init_memory_less_node(int nid)
 	 */
 }
 
+/*
+ * Generic Initiator Nodes may have neither CPU nor Memory.
+ * At this stage if either of the others were present we would
+ * already be online.
+ */
+void __init init_gi_nodes(void)
+{
+	int nid;
+
+	for_each_node_state(nid, N_GENERIC_INITIATOR)
+		if (!node_online(nid))
+			init_memory_less_node(nid);
+}
+
 /*
  * Setup early cpu_to_node.
  *
-- 
2.19.1


^ permalink raw reply	[flat|nested] 7+ messages in thread

* [PATCH 4/4 V3] ACPI: Let ACPI know we support Generic Initiator Affinity Structures
  2019-04-15 17:49 [PATCH 0/4 V3] ACPI: Support generic initiator proximity domains Jonathan Cameron
                   ` (2 preceding siblings ...)
  2019-04-15 17:49 ` [PATCH 3/4 V3] x86: Support Generic Initiator only proximity domains Jonathan Cameron
@ 2019-04-15 17:49 ` Jonathan Cameron
  2019-05-28 11:31 ` [PATCH 0/4 V3] ACPI: Support generic initiator proximity domains Jonathan Cameron
  4 siblings, 0 replies; 7+ messages in thread
From: Jonathan Cameron @ 2019-04-15 17:49 UTC (permalink / raw)
  To: linux-mm, linux-acpi, linux-kernel, linux-arm-kernel
  Cc: Jérôme Glisse, Keith Busch, Rafael J . Wysocki,
	linuxarm, Andrew Morton, Jonathan Cameron

Until we tell ACPI that we support generic initiators, it will have
to operate in fall back domain mode and all _PXM entries should
be on existing non GI domains.

This patch sets the relevant OSC bit to make that happen.

Note that this currently doesn't take into account whether we have the relevant
setup code for a given architecture.  Do we want to make this optional, or
should the initial patch set just enable it for all ACPI supporting architectures?

Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/acpi/bus.c   | 1 +
 include/linux/acpi.h | 1 +
 2 files changed, 2 insertions(+)

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
index eec263c9019e..ef251f454a5b 100644
--- a/drivers/acpi/bus.c
+++ b/drivers/acpi/bus.c
@@ -315,6 +315,7 @@ static void acpi_bus_osc_support(void)
 
 	capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_HOTPLUG_OST_SUPPORT;
 	capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_PCLPI_SUPPORT;
+	capbuf[OSC_SUPPORT_DWORD] |= OSC_SB_GENERIC_INITIATOR_SUPPORT;
 
 #ifdef CONFIG_X86
 	if (boot_cpu_has(X86_FEATURE_HWP)) {
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index d5dcebd7aad3..cc68b2ad0630 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -503,6 +503,7 @@ acpi_status acpi_run_osc(acpi_handle handle, struct acpi_osc_context *context);
 #define OSC_SB_PCLPI_SUPPORT			0x00000080
 #define OSC_SB_OSLPI_SUPPORT			0x00000100
 #define OSC_SB_CPC_DIVERSE_HIGH_SUPPORT		0x00001000
+#define OSC_SB_GENERIC_INITIATOR_SUPPORT	0x00002000
 
 extern bool osc_sb_apei_support_acked;
 extern bool osc_pc_lpi_support_confirmed;
-- 
2.19.1


^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH 0/4 V3] ACPI: Support generic initiator proximity domains
  2019-04-15 17:49 [PATCH 0/4 V3] ACPI: Support generic initiator proximity domains Jonathan Cameron
                   ` (3 preceding siblings ...)
  2019-04-15 17:49 ` [PATCH 4/4 V3] ACPI: Let ACPI know we support Generic Initiator Affinity Structures Jonathan Cameron
@ 2019-05-28 11:31 ` Jonathan Cameron
  2019-06-25  9:20   ` Jonathan Cameron
  4 siblings, 1 reply; 7+ messages in thread
From: Jonathan Cameron @ 2019-05-28 11:31 UTC (permalink / raw)
  To: linux-mm, linux-acpi, linux-kernel, linux-arm-kernel
  Cc: Jérôme Glisse, Keith Busch, Rafael J . Wysocki,
	linuxarm, Andrew Morton

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@huawei.com> 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(-)
> 



^ permalink raw reply	[flat|nested] 7+ messages in thread

* Re: [PATCH 0/4 V3] ACPI: Support generic initiator proximity domains
  2019-05-28 11:31 ` [PATCH 0/4 V3] ACPI: Support generic initiator proximity domains Jonathan Cameron
@ 2019-06-25  9:20   ` Jonathan Cameron
  0 siblings, 0 replies; 7+ messages in thread
From: Jonathan Cameron @ 2019-06-25  9:20 UTC (permalink / raw)
  To: linux-mm, linux-acpi, linux-kernel, linux-arm-kernel
  Cc: Keith Busch, Jérôme Glisse, Rafael J . Wysocki,
	linuxarm, Andrew Morton

On Tue, 28 May 2019 12:31:58 +0100
Jonathan Cameron <jonathan.cameron@huawei.com> wrote:
Hi All,

This is your periodic Generic Initiator reminder service.  I'm still looking
for review on all aspects of this series.

* ACPI for the table parsing code.
* ARM64 for the architecture handling
* x86 for the architecture handling.
* Generic MM for the overall approach. In some sense it's not mm related in
  of itself (as otherwise they wouldn't be Generic Initiator domains) but
  it does result in different NUMA policy decisions from the current status
  hence mm input would be great.

Any suggestions on people to add to the CC list to try and make some progress
on this welcome as well.

If I don't hear anything I'll do a rebase post the coming merge window and
resend.

Thanks,

Jonathan

> 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@huawei.com> 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(-)
> >   
> 
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel



^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2019-06-25  9:20 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-04-15 17:49 [PATCH 0/4 V3] ACPI: Support generic initiator proximity domains Jonathan Cameron
2019-04-15 17:49 ` [PATCH 1/4 V3] ACPI: Support Generic Initiator only domains Jonathan Cameron
2019-04-15 17:49 ` [PATCH 2/4 V3] arm64: " Jonathan Cameron
2019-04-15 17:49 ` [PATCH 3/4 V3] x86: Support Generic Initiator only proximity domains Jonathan Cameron
2019-04-15 17:49 ` [PATCH 4/4 V3] ACPI: Let ACPI know we support Generic Initiator Affinity Structures Jonathan Cameron
2019-05-28 11:31 ` [PATCH 0/4 V3] ACPI: Support generic initiator proximity domains Jonathan Cameron
2019-06-25  9:20   ` Jonathan Cameron

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