[PATCH v6 0/6] Add support for FORM2 associativity

[PATCH v6 0/6] Add support for FORM2 associativity

[Aneesh Kumar K.V]

Form2 associativity adds a much more flexible NUMA topology layout
than what is provided by Form1. More details can be found in patch 7.

$ numactl -H
...
node distances:
node   0   1   2   3 
  0:  10  11  222  33 
  1:  44  10  55  66 
  2:  77  88  10  99 
  3:  101  121  132  10 
$

After DAX kmem memory add
# numactl -H
available: 5 nodes (0-4)
...
node distances:
node   0   1   2   3   4 
  0:  10  11  222  33  240 
  1:  44  10  55  66  255 
  2:  77  88  10  99  255 
  3:  101  121  132  10  230 
  4:  255  255  255  230  10 


PAPR SCM now use the numa distance details to find the numa_node and target_node
for the device.

kvaneesh@ubuntu-guest:~$ ndctl  list -N -v 
[
  {
    "dev":"namespace0.0",
    "mode":"devdax",
    "map":"dev",
    "size":1071644672,
    "uuid":"d333d867-3f57-44c8-b386-d4d3abdc2bf2",
    "raw_uuid":"915361ad-fe6a-42dd-848f-d6dc9f5af362",
    "daxregion":{
      "id":0,
      "size":1071644672,
      "devices":[
        {
          "chardev":"dax0.0",
          "size":1071644672,
          "target_node":4,
          "mode":"devdax"
        }
      ]
    },
    "align":2097152,
    "numa_node":3
  }
]
kvaneesh@ubuntu-guest:~$ 


The above output is with a Qemu command line

-numa node,nodeid=4 \
-numa dist,src=0,dst=1,val=11 -numa dist,src=0,dst=2,val=222 -numa dist,src=0,dst=3,val=33 -numa dist,src=0,dst=4,val=240 \
-numa dist,src=1,dst=0,val=44 -numa dist,src=1,dst=2,val=55 -numa dist,src=1,dst=3,val=66 -numa dist,src=1,dst=4,val=255 \
-numa dist,src=2,dst=0,val=77 -numa dist,src=2,dst=1,val=88 -numa dist,src=2,dst=3,val=99 -numa dist,src=2,dst=4,val=255 \
-numa dist,src=3,dst=0,val=101 -numa dist,src=3,dst=1,val=121 -numa dist,src=3,dst=2,val=132 -numa dist,src=3,dst=4,val=230 \
-numa dist,src=4,dst=0,val=255 -numa dist,src=4,dst=1,val=255 -numa dist,src=4,dst=2,val=255 -numa dist,src=4,dst=3,val=230 \
-object memory-backend-file,id=memnvdimm1,prealloc=yes,mem-path=$PMEM_DISK,share=yes,size=${PMEM_SIZE}  \
-device nvdimm,label-size=128K,memdev=memnvdimm1,id=nvdimm1,slot=4,uuid=72511b67-0b3b-42fd-8d1d-5be3cae8bcaa,node=4

Qemu changes can be found at https://lore.kernel.org/qemu-devel/20210616011944.2996399-1-danielhb413@gmail.com/

Changes from v5:
* Fix build error reported by kernel test robot
* Address review feedback 

Changes from v4:
* Drop DLPAR related device tree property for now because both Qemu nor PowerVM
  will provide the distance details of all possible NUMA nodes during boot.
* Rework numa distance code based on review feedback.

Changes from v3:
* Drop PAPR SCM specific changes and depend completely on NUMA distance information.

Changes from v2:
* Add nvdimm list to Cc:
* update PATCH 8 commit message.

Changes from v1:
* Update FORM2 documentation.
* rename max_domain_index to max_associativity_domain_index


Aneesh Kumar K.V (6):
  powerpc/pseries: rename min_common_depth to primary_domain_index
  powerpc/pseries: Rename TYPE1_AFFINITY to FORM1_AFFINITY
  powerpc/pseries: Consolidate different NUMA distance update code paths
  powerpc/pseries: Add a helper for form1 cpu distance
  powerpc/pseries: Add support for FORM2 associativity
  powerpc/pseries: Consolidate form1 distance initialization into a
    helper

 Documentation/powerpc/associativity.rst       | 103 ++++
 arch/powerpc/include/asm/firmware.h           |   7 +-
 arch/powerpc/include/asm/prom.h               |   3 +-
 arch/powerpc/include/asm/topology.h           |   6 +-
 arch/powerpc/kernel/prom_init.c               |   3 +-
 arch/powerpc/mm/numa.c                        | 440 ++++++++++++++----
 arch/powerpc/platforms/pseries/firmware.c     |   3 +-
 arch/powerpc/platforms/pseries/hotplug-cpu.c  |   2 +
 .../platforms/pseries/hotplug-memory.c        |   2 +
 arch/powerpc/platforms/pseries/lpar.c         |   4 +-
 10 files changed, 462 insertions(+), 111 deletions(-)
 create mode 100644 Documentation/powerpc/associativity.rst

-- 
2.31.1

[PATCH v6 1/6] powerpc/pseries: rename min_common_depth to primary_domain_index

[Aneesh Kumar K.V]

No functional change in this patch.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 arch/powerpc/mm/numa.c | 38 +++++++++++++++++++-------------------
 1 file changed, 19 insertions(+), 19 deletions(-)

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index f2bf98bdcea2..8365b298ec48 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -51,7 +51,7 @@ EXPORT_SYMBOL(numa_cpu_lookup_table);
 EXPORT_SYMBOL(node_to_cpumask_map);
 EXPORT_SYMBOL(node_data);
 
-static int min_common_depth;
+static int primary_domain_index;
 static int n_mem_addr_cells, n_mem_size_cells;
 static int form1_affinity;
 
@@ -232,8 +232,8 @@ static int associativity_to_nid(const __be32 *associativity)
 	if (!numa_enabled)
 		goto out;
 
-	if (of_read_number(associativity, 1) >= min_common_depth)
-		nid = of_read_number(&associativity[min_common_depth], 1);
+	if (of_read_number(associativity, 1) >= primary_domain_index)
+		nid = of_read_number(&associativity[primary_domain_index], 1);
 
 	/* POWER4 LPAR uses 0xffff as invalid node */
 	if (nid == 0xffff || nid >= nr_node_ids)
@@ -284,9 +284,9 @@ int of_node_to_nid(struct device_node *device)
 }
 EXPORT_SYMBOL(of_node_to_nid);
 
-static int __init find_min_common_depth(void)
+static int __init find_primary_domain_index(void)
 {
-	int depth;
+	int index;
 	struct device_node *root;
 
 	if (firmware_has_feature(FW_FEATURE_OPAL))
@@ -326,7 +326,7 @@ static int __init find_min_common_depth(void)
 	}
 
 	if (form1_affinity) {
-		depth = of_read_number(distance_ref_points, 1);
+		index = of_read_number(distance_ref_points, 1);
 	} else {
 		if (distance_ref_points_depth < 2) {
 			printk(KERN_WARNING "NUMA: "
@@ -334,7 +334,7 @@ static int __init find_min_common_depth(void)
 			goto err;
 		}
 
-		depth = of_read_number(&distance_ref_points[1], 1);
+		index = of_read_number(&distance_ref_points[1], 1);
 	}
 
 	/*
@@ -348,7 +348,7 @@ static int __init find_min_common_depth(void)
 	}
 
 	of_node_put(root);
-	return depth;
+	return index;
 
 err:
 	of_node_put(root);
@@ -437,16 +437,16 @@ int of_drconf_to_nid_single(struct drmem_lmb *lmb)
 	int nid = default_nid;
 	int rc, index;
 
-	if ((min_common_depth < 0) || !numa_enabled)
+	if ((primary_domain_index < 0) || !numa_enabled)
 		return default_nid;
 
 	rc = of_get_assoc_arrays(&aa);
 	if (rc)
 		return default_nid;
 
-	if (min_common_depth <= aa.array_sz &&
+	if (primary_domain_index <= aa.array_sz &&
 	    !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) {
-		index = lmb->aa_index * aa.array_sz + min_common_depth - 1;
+		index = lmb->aa_index * aa.array_sz + primary_domain_index - 1;
 		nid = of_read_number(&aa.arrays[index], 1);
 
 		if (nid == 0xffff || nid >= nr_node_ids)
@@ -708,18 +708,18 @@ static int __init parse_numa_properties(void)
 		return -1;
 	}
 
-	min_common_depth = find_min_common_depth();
+	primary_domain_index = find_primary_domain_index();
 
-	if (min_common_depth < 0) {
+	if (primary_domain_index < 0) {
 		/*
-		 * if we fail to parse min_common_depth from device tree
+		 * if we fail to parse primary_domain_index from device tree
 		 * mark the numa disabled, boot with numa disabled.
 		 */
 		numa_enabled = false;
-		return min_common_depth;
+		return primary_domain_index;
 	}
 
-	dbg("NUMA associativity depth for CPU/Memory: %d\n", min_common_depth);
+	dbg("NUMA associativity depth for CPU/Memory: %d\n", primary_domain_index);
 
 	/*
 	 * Even though we connect cpus to numa domains later in SMP
@@ -919,14 +919,14 @@ static void __init find_possible_nodes(void)
 			goto out;
 	}
 
-	max_nodes = of_read_number(&domains[min_common_depth], 1);
+	max_nodes = of_read_number(&domains[primary_domain_index], 1);
 	for (i = 0; i < max_nodes; i++) {
 		if (!node_possible(i))
 			node_set(i, node_possible_map);
 	}
 
 	prop_length /= sizeof(int);
-	if (prop_length > min_common_depth + 2)
+	if (prop_length > primary_domain_index + 2)
 		coregroup_enabled = 1;
 
 out:
@@ -1259,7 +1259,7 @@ int cpu_to_coregroup_id(int cpu)
 		goto out;
 
 	index = of_read_number(associativity, 1);
-	if (index > min_common_depth + 1)
+	if (index > primary_domain_index + 1)
 		return of_read_number(&associativity[index - 1], 1);
 
 out:
-- 
2.31.1

[PATCH v6 2/6] powerpc/pseries: Rename TYPE1_AFFINITY to FORM1_AFFINITY

[Aneesh Kumar K.V]

Also make related code cleanup that will allow adding FORM2_AFFINITY in
later patches. No functional change in this patch.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 arch/powerpc/include/asm/firmware.h       |  4 +--
 arch/powerpc/include/asm/prom.h           |  2 +-
 arch/powerpc/kernel/prom_init.c           |  2 +-
 arch/powerpc/mm/numa.c                    | 35 ++++++++++++++---------
 arch/powerpc/platforms/pseries/firmware.c |  2 +-
 5 files changed, 26 insertions(+), 19 deletions(-)

diff --git a/arch/powerpc/include/asm/firmware.h b/arch/powerpc/include/asm/firmware.h
index 7604673787d6..60b631161360 100644
--- a/arch/powerpc/include/asm/firmware.h
+++ b/arch/powerpc/include/asm/firmware.h
@@ -44,7 +44,7 @@
 #define FW_FEATURE_OPAL		ASM_CONST(0x0000000010000000)
 #define FW_FEATURE_SET_MODE	ASM_CONST(0x0000000040000000)
 #define FW_FEATURE_BEST_ENERGY	ASM_CONST(0x0000000080000000)
-#define FW_FEATURE_TYPE1_AFFINITY ASM_CONST(0x0000000100000000)
+#define FW_FEATURE_FORM1_AFFINITY ASM_CONST(0x0000000100000000)
 #define FW_FEATURE_PRRN		ASM_CONST(0x0000000200000000)
 #define FW_FEATURE_DRMEM_V2	ASM_CONST(0x0000000400000000)
 #define FW_FEATURE_DRC_INFO	ASM_CONST(0x0000000800000000)
@@ -69,7 +69,7 @@ enum {
 		FW_FEATURE_SPLPAR | FW_FEATURE_LPAR |
 		FW_FEATURE_CMO | FW_FEATURE_VPHN | FW_FEATURE_XCMO |
 		FW_FEATURE_SET_MODE | FW_FEATURE_BEST_ENERGY |
-		FW_FEATURE_TYPE1_AFFINITY | FW_FEATURE_PRRN |
+		FW_FEATURE_FORM1_AFFINITY | FW_FEATURE_PRRN |
 		FW_FEATURE_HPT_RESIZE | FW_FEATURE_DRMEM_V2 |
 		FW_FEATURE_DRC_INFO | FW_FEATURE_BLOCK_REMOVE |
 		FW_FEATURE_PAPR_SCM | FW_FEATURE_ULTRAVISOR |
diff --git a/arch/powerpc/include/asm/prom.h b/arch/powerpc/include/asm/prom.h
index 324a13351749..df9fec9d232c 100644
--- a/arch/powerpc/include/asm/prom.h
+++ b/arch/powerpc/include/asm/prom.h
@@ -147,7 +147,7 @@ extern int of_read_drc_info_cell(struct property **prop,
 #define OV5_MSI			0x0201	/* PCIe/MSI support */
 #define OV5_CMO			0x0480	/* Cooperative Memory Overcommitment */
 #define OV5_XCMO		0x0440	/* Page Coalescing */
-#define OV5_TYPE1_AFFINITY	0x0580	/* Type 1 NUMA affinity */
+#define OV5_FORM1_AFFINITY	0x0580	/* FORM1 NUMA affinity */
 #define OV5_PRRN		0x0540	/* Platform Resource Reassignment */
 #define OV5_HP_EVT		0x0604	/* Hot Plug Event support */
 #define OV5_RESIZE_HPT		0x0601	/* Hash Page Table resizing */
diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index a5bf355ce1d6..57db605ad33a 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -1096,7 +1096,7 @@ static const struct ibm_arch_vec ibm_architecture_vec_template __initconst = {
 #else
 		0,
 #endif
-		.associativity = OV5_FEAT(OV5_TYPE1_AFFINITY) | OV5_FEAT(OV5_PRRN),
+		.associativity = OV5_FEAT(OV5_FORM1_AFFINITY) | OV5_FEAT(OV5_PRRN),
 		.bin_opts = OV5_FEAT(OV5_RESIZE_HPT) | OV5_FEAT(OV5_HP_EVT),
 		.micro_checkpoint = 0,
 		.reserved0 = 0,
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index 8365b298ec48..368719b14dcc 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -53,7 +53,10 @@ EXPORT_SYMBOL(node_data);
 
 static int primary_domain_index;
 static int n_mem_addr_cells, n_mem_size_cells;
-static int form1_affinity;
+
+#define FORM0_AFFINITY 0
+#define FORM1_AFFINITY 1
+static int affinity_form;
 
 #define MAX_DISTANCE_REF_POINTS 4
 static int distance_ref_points_depth;
@@ -190,7 +193,7 @@ int __node_distance(int a, int b)
 	int i;
 	int distance = LOCAL_DISTANCE;
 
-	if (!form1_affinity)
+	if (affinity_form == FORM0_AFFINITY)
 		return ((a == b) ? LOCAL_DISTANCE : REMOTE_DISTANCE);
 
 	for (i = 0; i < distance_ref_points_depth; i++) {
@@ -210,7 +213,7 @@ static void initialize_distance_lookup_table(int nid,
 {
 	int i;
 
-	if (!form1_affinity)
+	if (affinity_form != FORM1_AFFINITY)
 		return;
 
 	for (i = 0; i < distance_ref_points_depth; i++) {
@@ -289,6 +292,17 @@ static int __init find_primary_domain_index(void)
 	int index;
 	struct device_node *root;
 
+	/*
+	 * Check for which form of affinity.
+	 */
+	if (firmware_has_feature(FW_FEATURE_OPAL)) {
+		affinity_form = FORM1_AFFINITY;
+	} else if (firmware_has_feature(FW_FEATURE_FORM1_AFFINITY)) {
+		dbg("Using form 1 affinity\n");
+		affinity_form = FORM1_AFFINITY;
+	} else
+		affinity_form = FORM0_AFFINITY;
+
 	if (firmware_has_feature(FW_FEATURE_OPAL))
 		root = of_find_node_by_path("/ibm,opal");
 	else
@@ -318,23 +332,16 @@ static int __init find_primary_domain_index(void)
 	}
 
 	distance_ref_points_depth /= sizeof(int);
-
-	if (firmware_has_feature(FW_FEATURE_OPAL) ||
-	    firmware_has_feature(FW_FEATURE_TYPE1_AFFINITY)) {
-		dbg("Using form 1 affinity\n");
-		form1_affinity = 1;
-	}
-
-	if (form1_affinity) {
-		index = of_read_number(distance_ref_points, 1);
-	} else {
+	if (affinity_form == FORM0_AFFINITY) {
 		if (distance_ref_points_depth < 2) {
 			printk(KERN_WARNING "NUMA: "
-				"short ibm,associativity-reference-points\n");
+			       "short ibm,associativity-reference-points\n");
 			goto err;
 		}
 
 		index = of_read_number(&distance_ref_points[1], 1);
+	} else {
+		index = of_read_number(distance_ref_points, 1);
 	}
 
 	/*
diff --git a/arch/powerpc/platforms/pseries/firmware.c b/arch/powerpc/platforms/pseries/firmware.c
index 4c7b7f5a2ebc..5d4c2bc20bba 100644
--- a/arch/powerpc/platforms/pseries/firmware.c
+++ b/arch/powerpc/platforms/pseries/firmware.c
@@ -119,7 +119,7 @@ struct vec5_fw_feature {
 
 static __initdata struct vec5_fw_feature
 vec5_fw_features_table[] = {
-	{FW_FEATURE_TYPE1_AFFINITY,	OV5_TYPE1_AFFINITY},
+	{FW_FEATURE_FORM1_AFFINITY,	OV5_FORM1_AFFINITY},
 	{FW_FEATURE_PRRN,		OV5_PRRN},
 	{FW_FEATURE_DRMEM_V2,		OV5_DRMEM_V2},
 	{FW_FEATURE_DRC_INFO,		OV5_DRC_INFO},
-- 
2.31.1

[PATCH v6 3/6] powerpc/pseries: Consolidate different NUMA distance update code paths

[Aneesh Kumar K.V]

The associativity details of the newly added resourced are collected from
the hypervisor via "ibm,configure-connector" rtas call. Update the numa
distance details of the newly added numa node after the above call.

Instead of updating NUMA distance every time we lookup a node id
from the associativity property, add helpers that can be used
during boot which does this only once. Also remove the distance
update from node id lookup helpers.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 arch/powerpc/include/asm/topology.h           |   2 +
 arch/powerpc/mm/numa.c                        | 178 +++++++++++++-----
 arch/powerpc/platforms/pseries/hotplug-cpu.c  |   2 +
 .../platforms/pseries/hotplug-memory.c        |   2 +
 4 files changed, 138 insertions(+), 46 deletions(-)

diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index e4db64c0e184..a6425a70c37b 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h
@@ -64,6 +64,7 @@ static inline int early_cpu_to_node(int cpu)
 }
 
 int of_drconf_to_nid_single(struct drmem_lmb *lmb);
+void update_numa_distance(struct device_node *node);
 
 #else
 
@@ -93,6 +94,7 @@ static inline int of_drconf_to_nid_single(struct drmem_lmb *lmb)
 	return first_online_node;
 }
 
+static inline void update_numa_distance(struct device_node *node) {}
 #endif /* CONFIG_NUMA */
 
 #if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR)
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index 368719b14dcc..c695faf67d68 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -208,22 +208,6 @@ int __node_distance(int a, int b)
 }
 EXPORT_SYMBOL(__node_distance);
 
-static void initialize_distance_lookup_table(int nid,
-		const __be32 *associativity)
-{
-	int i;
-
-	if (affinity_form != FORM1_AFFINITY)
-		return;
-
-	for (i = 0; i < distance_ref_points_depth; i++) {
-		const __be32 *entry;
-
-		entry = &associativity[be32_to_cpu(distance_ref_points[i]) - 1];
-		distance_lookup_table[nid][i] = of_read_number(entry, 1);
-	}
-}
-
 /*
  * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA
  * info is found.
@@ -241,15 +225,6 @@ static int associativity_to_nid(const __be32 *associativity)
 	/* POWER4 LPAR uses 0xffff as invalid node */
 	if (nid == 0xffff || nid >= nr_node_ids)
 		nid = NUMA_NO_NODE;
-
-	if (nid > 0 &&
-		of_read_number(associativity, 1) >= distance_ref_points_depth) {
-		/*
-		 * Skip the length field and send start of associativity array
-		 */
-		initialize_distance_lookup_table(nid, associativity + 1);
-	}
-
 out:
 	return nid;
 }
@@ -287,6 +262,48 @@ int of_node_to_nid(struct device_node *device)
 }
 EXPORT_SYMBOL(of_node_to_nid);
 
+static void __initialize_form1_numa_distance(const __be32 *associativity)
+{
+	int i, nid;
+
+	if (affinity_form != FORM1_AFFINITY)
+		return;
+
+	nid = associativity_to_nid(associativity);
+	if (nid != NUMA_NO_NODE) {
+		for (i = 0; i < distance_ref_points_depth; i++) {
+			const __be32 *entry;
+
+			entry = &associativity[be32_to_cpu(distance_ref_points[i])];
+			distance_lookup_table[nid][i] = of_read_number(entry, 1);
+		}
+	}
+}
+
+static void initialize_form1_numa_distance(struct device_node *node)
+{
+	const __be32 *associativity;
+
+	associativity = of_get_associativity(node);
+	if (!associativity)
+		return;
+
+	__initialize_form1_numa_distance(associativity);
+}
+
+/*
+ * Used to update distance information w.r.t newly added node.
+ */
+void update_numa_distance(struct device_node *node)
+{
+	if (affinity_form == FORM0_AFFINITY)
+		return;
+	else if (affinity_form == FORM1_AFFINITY) {
+		initialize_form1_numa_distance(node);
+		return;
+	}
+}
+
 static int __init find_primary_domain_index(void)
 {
 	int index;
@@ -433,6 +450,48 @@ static int of_get_assoc_arrays(struct assoc_arrays *aa)
 	return 0;
 }
 
+static int get_nid_and_numa_distance(struct drmem_lmb *lmb)
+{
+	struct assoc_arrays aa = { .arrays = NULL };
+	int default_nid = NUMA_NO_NODE;
+	int nid = default_nid;
+	int rc, index;
+
+	if ((primary_domain_index < 0) || !numa_enabled)
+		return default_nid;
+
+	rc = of_get_assoc_arrays(&aa);
+	if (rc)
+		return default_nid;
+
+	if (primary_domain_index <= aa.array_sz &&
+	    !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) {
+		index = lmb->aa_index * aa.array_sz + primary_domain_index - 1;
+		nid = of_read_number(&aa.arrays[index], 1);
+
+		if (nid == 0xffff || nid >= nr_node_ids)
+			nid = default_nid;
+		if (nid > 0 && affinity_form == FORM1_AFFINITY) {
+			int i;
+			const __be32 *associativity;
+
+			index = lmb->aa_index * aa.array_sz;
+			associativity = &aa.arrays[index];
+			/*
+			 * lookup array associativity entries have different format
+			 * There is no length of the array as the first element.
+			 */
+			for (i = 0; i < distance_ref_points_depth; i++) {
+				const __be32 *entry;
+
+				entry = &associativity[be32_to_cpu(distance_ref_points[i]) - 1];
+				distance_lookup_table[nid][i] = of_read_number(entry, 1);
+			}
+		}
+	}
+	return nid;
+}
+
 /*
  * This is like of_node_to_nid_single() for memory represented in the
  * ibm,dynamic-reconfiguration-memory node.
@@ -458,21 +517,14 @@ int of_drconf_to_nid_single(struct drmem_lmb *lmb)
 
 		if (nid == 0xffff || nid >= nr_node_ids)
 			nid = default_nid;
-
-		if (nid > 0) {
-			index = lmb->aa_index * aa.array_sz;
-			initialize_distance_lookup_table(nid,
-							&aa.arrays[index]);
-		}
 	}
-
 	return nid;
 }
 
 #ifdef CONFIG_PPC_SPLPAR
-static int vphn_get_nid(long lcpu)
+
+static int __vphn_get_associativity(long lcpu, __be32 *associativity)
 {
-	__be32 associativity[VPHN_ASSOC_BUFSIZE] = {0};
 	long rc, hwid;
 
 	/*
@@ -492,12 +544,30 @@ static int vphn_get_nid(long lcpu)
 
 		rc = hcall_vphn(hwid, VPHN_FLAG_VCPU, associativity);
 		if (rc == H_SUCCESS)
-			return associativity_to_nid(associativity);
+			return 0;
 	}
 
+	return -1;
+}
+
+static int vphn_get_nid(long lcpu)
+{
+	__be32 associativity[VPHN_ASSOC_BUFSIZE] = {0};
+
+
+	if (!__vphn_get_associativity(lcpu, associativity))
+		return associativity_to_nid(associativity);
+
 	return NUMA_NO_NODE;
+
 }
 #else
+
+static int __vphn_get_associativity(long lcpu, __be32 *associativity)
+{
+	return -1;
+}
+
 static int vphn_get_nid(long unused)
 {
 	return NUMA_NO_NODE;
@@ -692,7 +762,7 @@ static int __init numa_setup_drmem_lmb(struct drmem_lmb *lmb,
 			size = read_n_cells(n_mem_size_cells, usm);
 		}
 
-		nid = of_drconf_to_nid_single(lmb);
+		nid = get_nid_and_numa_distance(lmb);
 		fake_numa_create_new_node(((base + size) >> PAGE_SHIFT),
 					  &nid);
 		node_set_online(nid);
@@ -709,6 +779,7 @@ static int __init parse_numa_properties(void)
 	struct device_node *memory;
 	int default_nid = 0;
 	unsigned long i;
+	const __be32 *associativity;
 
 	if (numa_enabled == 0) {
 		printk(KERN_WARNING "NUMA disabled by user\n");
@@ -734,18 +805,30 @@ static int __init parse_numa_properties(void)
 	 * each node to be onlined must have NODE_DATA etc backing it.
 	 */
 	for_each_present_cpu(i) {
+		__be32 vphn_assoc[VPHN_ASSOC_BUFSIZE];
 		struct device_node *cpu;
-		int nid = vphn_get_nid(i);
+		int nid = NUMA_NO_NODE;
 
-		/*
-		 * Don't fall back to default_nid yet -- we will plug
-		 * cpus into nodes once the memory scan has discovered
-		 * the topology.
-		 */
-		if (nid == NUMA_NO_NODE) {
+		memset(vphn_assoc, 0, VPHN_ASSOC_BUFSIZE * sizeof(__be32));
+
+		if (__vphn_get_associativity(i, vphn_assoc) == 0) {
+			nid = associativity_to_nid(vphn_assoc);
+			__initialize_form1_numa_distance(vphn_assoc);
+		} else {
+
+			/*
+			 * Don't fall back to default_nid yet -- we will plug
+			 * cpus into nodes once the memory scan has discovered
+			 * the topology.
+			 */
 			cpu = of_get_cpu_node(i, NULL);
 			BUG_ON(!cpu);
-			nid = of_node_to_nid_single(cpu);
+
+			associativity = of_get_associativity(cpu);
+			if (associativity) {
+				nid = associativity_to_nid(associativity);
+				__initialize_form1_numa_distance(associativity);
+			}
 			of_node_put(cpu);
 		}
 
@@ -781,8 +864,11 @@ static int __init parse_numa_properties(void)
 		 * have associativity properties.  If none, then
 		 * everything goes to default_nid.
 		 */
-		nid = of_node_to_nid_single(memory);
-		if (nid < 0)
+		associativity = of_get_associativity(memory);
+		if (associativity) {
+			nid = associativity_to_nid(associativity);
+			__initialize_form1_numa_distance(associativity);
+		} else
 			nid = default_nid;
 
 		fake_numa_create_new_node(((start + size) >> PAGE_SHIFT), &nid);
diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
index 7e970f81d8ff..778b6ab35f0d 100644
--- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
+++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
@@ -498,6 +498,8 @@ static ssize_t dlpar_cpu_add(u32 drc_index)
 		return saved_rc;
 	}
 
+	update_numa_distance(dn);
+
 	rc = dlpar_online_cpu(dn);
 	if (rc) {
 		saved_rc = rc;
diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
index 377d852f5a9a..ee1d81d7e54a 100644
--- a/arch/powerpc/platforms/pseries/hotplug-memory.c
+++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
@@ -180,6 +180,8 @@ static int update_lmb_associativity_index(struct drmem_lmb *lmb)
 		return -ENODEV;
 	}
 
+	update_numa_distance(lmb_node);
+
 	dr_node = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
 	if (!dr_node) {
 		dlpar_free_cc_nodes(lmb_node);
-- 
2.31.1

[PATCH v6 4/6] powerpc/pseries: Add a helper for form1 cpu distance

[Aneesh Kumar K.V]

This helper is only used with the dispatch trace log collection.
A later patch will add Form2 affinity support and this change helps
in keeping that simpler. Also add a comment explaining we don't expect
the code to be called with FORM0

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 arch/powerpc/include/asm/topology.h   |  4 ++--
 arch/powerpc/mm/numa.c                | 10 +++++++++-
 arch/powerpc/platforms/pseries/lpar.c |  4 ++--
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
index a6425a70c37b..a4712ecad3e9 100644
--- a/arch/powerpc/include/asm/topology.h
+++ b/arch/powerpc/include/asm/topology.h
@@ -36,7 +36,7 @@ static inline int pcibus_to_node(struct pci_bus *bus)
 				 cpu_all_mask :				\
 				 cpumask_of_node(pcibus_to_node(bus)))
 
-extern int cpu_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc);
+int cpu_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc);
 extern int __node_distance(int, int);
 #define node_distance(a, b) __node_distance(a, b)
 
@@ -84,7 +84,7 @@ static inline void sysfs_remove_device_from_node(struct device *dev,
 
 static inline void update_numa_cpu_lookup_table(unsigned int cpu, int node) {}
 
-static inline int cpu_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
+static inline int cpu_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
 {
 	return 0;
 }
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index c695faf67d68..a244398a7766 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -166,7 +166,7 @@ static void unmap_cpu_from_node(unsigned long cpu)
 }
 #endif /* CONFIG_HOTPLUG_CPU || CONFIG_PPC_SPLPAR */
 
-int cpu_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
+static int __cpu_form1_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
 {
 	int dist = 0;
 
@@ -182,6 +182,14 @@ int cpu_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
 	return dist;
 }
 
+int cpu_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
+{
+	/* We should not get called with FORM0 */
+	VM_WARN_ON(affinity_form == FORM0_AFFINITY);
+
+	return __cpu_form1_relative_distance(cpu1_assoc, cpu2_assoc);
+}
+
 /* must hold reference to node during call */
 static const __be32 *of_get_associativity(struct device_node *dev)
 {
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index dab356e3ff87..afefbdfe768d 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -261,7 +261,7 @@ static int cpu_relative_dispatch_distance(int last_disp_cpu, int cur_disp_cpu)
 	if (!last_disp_cpu_assoc || !cur_disp_cpu_assoc)
 		return -EIO;
 
-	return cpu_distance(last_disp_cpu_assoc, cur_disp_cpu_assoc);
+	return cpu_relative_distance(last_disp_cpu_assoc, cur_disp_cpu_assoc);
 }
 
 static int cpu_home_node_dispatch_distance(int disp_cpu)
@@ -281,7 +281,7 @@ static int cpu_home_node_dispatch_distance(int disp_cpu)
 	if (!disp_cpu_assoc || !vcpu_assoc)
 		return -EIO;
 
-	return cpu_distance(disp_cpu_assoc, vcpu_assoc);
+	return cpu_relative_distance(disp_cpu_assoc, vcpu_assoc);
 }
 
 static void update_vcpu_disp_stat(int disp_cpu)
-- 
2.31.1

[PATCH v6 5/6] powerpc/pseries: Add support for FORM2 associativity

[Aneesh Kumar K.V]

PAPR interface currently supports two different ways of communicating resource
grouping details to the OS. These are referred to as Form 0 and Form 1
associativity grouping. Form 0 is the older format and is now considered
deprecated. This patch adds another resource grouping named FORM2.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 Documentation/powerpc/associativity.rst   | 103 +++++++++++++
 arch/powerpc/include/asm/firmware.h       |   3 +-
 arch/powerpc/include/asm/prom.h           |   1 +
 arch/powerpc/kernel/prom_init.c           |   3 +-
 arch/powerpc/mm/numa.c                    | 168 ++++++++++++++++++----
 arch/powerpc/platforms/pseries/firmware.c |   1 +
 6 files changed, 252 insertions(+), 27 deletions(-)
 create mode 100644 Documentation/powerpc/associativity.rst

diff --git a/Documentation/powerpc/associativity.rst b/Documentation/powerpc/associativity.rst
new file mode 100644
index 000000000000..b6c89706ca03
--- /dev/null
+++ b/Documentation/powerpc/associativity.rst
@@ -0,0 +1,103 @@
+============================
+NUMA resource associativity
+=============================
+
+Associativity represents the groupings of the various platform resources into
+domains of substantially similar mean performance relative to resources outside
+of that domain. Resources subsets of a given domain that exhibit better
+performance relative to each other than relative to other resources subsets
+are represented as being members of a sub-grouping domain. This performance
+characteristic is presented in terms of NUMA node distance within the Linux kernel.
+From the platform view, these groups are also referred to as domains.
+
+PAPR interface currently supports different ways of communicating these resource
+grouping details to the OS. These are referred to as Form 0, Form 1 and Form2
+associativity grouping. Form 0 is the oldest format and is now considered deprecated.
+
+Hypervisor indicates the type/form of associativity used via "ibm,architecture-vec-5 property".
+Bit 0 of byte 5 in the "ibm,architecture-vec-5" property indicates usage of Form 0 or Form 1.
+A value of 1 indicates the usage of Form 1 associativity. For Form 2 associativity
+bit 2 of byte 5 in the "ibm,architecture-vec-5" property is used.
+
+Form 0
+-----
+Form 0 associativity supports only two NUMA distances (LOCAL and REMOTE).
+
+Form 1
+-----
+With Form 1 a combination of ibm,associativity-reference-points, and ibm,associativity
+device tree properties are used to determine the NUMA distance between resource groups/domains.
+
+The “ibm,associativity” property contains a list of one or more numbers (domainID)
+representing the resource’s platform grouping domains.
+
+The “ibm,associativity-reference-points” property contains a list of one or more numbers
+(domainID index) that represents the 1 based ordinal in the associativity lists.
+The list of domainID indexes represents an increasing hierarchy of resource grouping.
+
+ex:
+{ primary domainID index, secondary domainID index, tertiary domainID index.. }
+
+Linux kernel uses the domainID at the primary domainID index as the NUMA node id.
+Linux kernel computes NUMA distance between two domains by recursively comparing
+if they belong to the same higher-level domains. For mismatch at every higher
+level of the resource group, the kernel doubles the NUMA distance between the
+comparing domains.
+
+Form 2
+-------
+Form 2 associativity format adds separate device tree properties representing NUMA node distance
+thereby making the node distance computation flexible. Form 2 also allows flexible primary
+domain numbering. With numa distance computation now detached from the index value in
+"ibm,associativity-reference-points" property, Form 2 allows a large number of primary domain
+ids at the same domainID index representing resource groups of different performance/latency
+characteristics.
+
+Hypervisor indicates the usage of FORM2 associativity using bit 2 of byte 5 in the
+"ibm,architecture-vec-5" property.
+
+"ibm,numa-lookup-index-table" property contains a list of one or more numbers representing
+the domainIDs present in the system. The offset of the domainID in this property is
+used as an index while computing numa distance information via "ibm,numa-distance-table".
+
+prop-encoded-array: The number N of the domainIDs encoded as with encode-int, followed by
+N domainID encoded as with encode-int
+
+For ex:
+"ibm,numa-lookup-index-table" =  {4, 0, 8, 250, 252}. The offset of domainID 8 (2) is used when
+computing the distance of domain 8 from other domains present in the system. For the rest of
+this document, this offset will be referred to as domain distance offset.
+
+"ibm,numa-distance-table" property contains a list of one or more numbers representing the NUMA
+distance between resource groups/domains present in the system.
+
+prop-encoded-array: The number N of the distance values encoded as with encode-int, followed by
+N distance values encoded as with encode-bytes. The max distance value we could encode is 255.
+The number N must be equal to the square of m where m is the number of domainIDs in the
+numa-lookup-index-table.
+
+For ex:
+ibm,numa-lookup-index-table =  {3, 0, 8, 40}
+ibm,numa-distance-table     =  {9:u32, 10:u8, 20:u8, 80:u8, 20:u8, 10:u8, 160:u8, 80:u8, 160:u8, 10:u8}
+
+  | 0    8   40
+--|------------
+  |
+0 | 10   20  80
+  |
+8 | 20   10  160
+  |
+40| 80   160  10
+
+A possible "ibm,associativity" property for resources in node 0, 8 and 40
+
+{ 3, 6, 7, 0 }
+{ 3, 6, 9, 8 }
+{ 3, 6, 7, 40}
+
+With "ibm,associativity-reference-points"  { 0x3 }
+
+"ibm,lookup-index-table" helps in having a compact representation of distance matrix.
+Since domainID can be sparse, the matrix of distances can also be effectively sparse.
+With "ibm,lookup-index-table" we can achieve a compact representation of
+distance information.
diff --git a/arch/powerpc/include/asm/firmware.h b/arch/powerpc/include/asm/firmware.h
index 60b631161360..97a3bd9ffeb9 100644
--- a/arch/powerpc/include/asm/firmware.h
+++ b/arch/powerpc/include/asm/firmware.h
@@ -53,6 +53,7 @@
 #define FW_FEATURE_ULTRAVISOR	ASM_CONST(0x0000004000000000)
 #define FW_FEATURE_STUFF_TCE	ASM_CONST(0x0000008000000000)
 #define FW_FEATURE_RPT_INVALIDATE ASM_CONST(0x0000010000000000)
+#define FW_FEATURE_FORM2_AFFINITY ASM_CONST(0x0000020000000000)
 
 #ifndef __ASSEMBLY__
 
@@ -73,7 +74,7 @@ enum {
 		FW_FEATURE_HPT_RESIZE | FW_FEATURE_DRMEM_V2 |
 		FW_FEATURE_DRC_INFO | FW_FEATURE_BLOCK_REMOVE |
 		FW_FEATURE_PAPR_SCM | FW_FEATURE_ULTRAVISOR |
-		FW_FEATURE_RPT_INVALIDATE,
+		FW_FEATURE_RPT_INVALIDATE | FW_FEATURE_FORM2_AFFINITY,
 	FW_FEATURE_PSERIES_ALWAYS = 0,
 	FW_FEATURE_POWERNV_POSSIBLE = FW_FEATURE_OPAL | FW_FEATURE_ULTRAVISOR,
 	FW_FEATURE_POWERNV_ALWAYS = 0,
diff --git a/arch/powerpc/include/asm/prom.h b/arch/powerpc/include/asm/prom.h
index df9fec9d232c..5c80152e8f18 100644
--- a/arch/powerpc/include/asm/prom.h
+++ b/arch/powerpc/include/asm/prom.h
@@ -149,6 +149,7 @@ extern int of_read_drc_info_cell(struct property **prop,
 #define OV5_XCMO		0x0440	/* Page Coalescing */
 #define OV5_FORM1_AFFINITY	0x0580	/* FORM1 NUMA affinity */
 #define OV5_PRRN		0x0540	/* Platform Resource Reassignment */
+#define OV5_FORM2_AFFINITY	0x0520	/* Form2 NUMA affinity */
 #define OV5_HP_EVT		0x0604	/* Hot Plug Event support */
 #define OV5_RESIZE_HPT		0x0601	/* Hash Page Table resizing */
 #define OV5_PFO_HW_RNG		0x1180	/* PFO Random Number Generator */
diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index 57db605ad33a..95a42d49e291 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -1096,7 +1096,8 @@ static const struct ibm_arch_vec ibm_architecture_vec_template __initconst = {
 #else
 		0,
 #endif
-		.associativity = OV5_FEAT(OV5_FORM1_AFFINITY) | OV5_FEAT(OV5_PRRN),
+		.associativity = OV5_FEAT(OV5_FORM1_AFFINITY) | OV5_FEAT(OV5_PRRN) |
+		OV5_FEAT(OV5_FORM2_AFFINITY),
 		.bin_opts = OV5_FEAT(OV5_RESIZE_HPT) | OV5_FEAT(OV5_HP_EVT),
 		.micro_checkpoint = 0,
 		.reserved0 = 0,
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index a244398a7766..fffb3c40f595 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -56,12 +56,17 @@ static int n_mem_addr_cells, n_mem_size_cells;
 
 #define FORM0_AFFINITY 0
 #define FORM1_AFFINITY 1
+#define FORM2_AFFINITY 2
 static int affinity_form;
 
 #define MAX_DISTANCE_REF_POINTS 4
 static int distance_ref_points_depth;
 static const __be32 *distance_ref_points;
 static int distance_lookup_table[MAX_NUMNODES][MAX_DISTANCE_REF_POINTS];
+static int numa_distance_table[MAX_NUMNODES][MAX_NUMNODES] = {
+	[0 ... MAX_NUMNODES - 1] = { [0 ... MAX_NUMNODES - 1] = -1 }
+};
+static int numa_id_index_table[MAX_NUMNODES] = { [0 ... MAX_NUMNODES - 1] = NUMA_NO_NODE };
 
 /*
  * Allocate node_to_cpumask_map based on number of available nodes
@@ -166,6 +171,44 @@ static void unmap_cpu_from_node(unsigned long cpu)
 }
 #endif /* CONFIG_HOTPLUG_CPU || CONFIG_PPC_SPLPAR */
 
+/*
+ * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA
+ * info is found.
+ */
+static int associativity_to_nid(const __be32 *associativity)
+{
+	int nid = NUMA_NO_NODE;
+
+	if (!numa_enabled)
+		goto out;
+
+	if (of_read_number(associativity, 1) >= primary_domain_index)
+		nid = of_read_number(&associativity[primary_domain_index], 1);
+
+	/* POWER4 LPAR uses 0xffff as invalid node */
+	if (nid == 0xffff || nid >= nr_node_ids)
+		nid = NUMA_NO_NODE;
+out:
+	return nid;
+}
+
+static int __cpu_form2_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
+{
+	int dist;
+	int node1, node2;
+
+	node1 = associativity_to_nid(cpu1_assoc);
+	node2 = associativity_to_nid(cpu2_assoc);
+
+	dist = numa_distance_table[node1][node2];
+	if (dist <= LOCAL_DISTANCE)
+		return 0;
+	else if (dist <= REMOTE_DISTANCE)
+		return 1;
+	else
+		return 2;
+}
+
 static int __cpu_form1_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
 {
 	int dist = 0;
@@ -186,8 +229,9 @@ int cpu_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
 {
 	/* We should not get called with FORM0 */
 	VM_WARN_ON(affinity_form == FORM0_AFFINITY);
-
-	return __cpu_form1_relative_distance(cpu1_assoc, cpu2_assoc);
+	if (affinity_form == FORM1_AFFINITY)
+		return __cpu_form1_relative_distance(cpu1_assoc, cpu2_assoc);
+	return __cpu_form2_relative_distance(cpu1_assoc, cpu2_assoc);
 }
 
 /* must hold reference to node during call */
@@ -201,7 +245,9 @@ int __node_distance(int a, int b)
 	int i;
 	int distance = LOCAL_DISTANCE;
 
-	if (affinity_form == FORM0_AFFINITY)
+	if (affinity_form == FORM2_AFFINITY)
+		return numa_distance_table[a][b];
+	else if (affinity_form == FORM0_AFFINITY)
 		return ((a == b) ? LOCAL_DISTANCE : REMOTE_DISTANCE);
 
 	for (i = 0; i < distance_ref_points_depth; i++) {
@@ -216,27 +262,6 @@ int __node_distance(int a, int b)
 }
 EXPORT_SYMBOL(__node_distance);
 
-/*
- * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA
- * info is found.
- */
-static int associativity_to_nid(const __be32 *associativity)
-{
-	int nid = NUMA_NO_NODE;
-
-	if (!numa_enabled)
-		goto out;
-
-	if (of_read_number(associativity, 1) >= primary_domain_index)
-		nid = of_read_number(&associativity[primary_domain_index], 1);
-
-	/* POWER4 LPAR uses 0xffff as invalid node */
-	if (nid == 0xffff || nid >= nr_node_ids)
-		nid = NUMA_NO_NODE;
-out:
-	return nid;
-}
-
 /* Returns the nid associated with the given device tree node,
  * or -1 if not found.
  */
@@ -304,12 +329,93 @@ static void initialize_form1_numa_distance(struct device_node *node)
  */
 void update_numa_distance(struct device_node *node)
 {
+	int nid;
+
 	if (affinity_form == FORM0_AFFINITY)
 		return;
 	else if (affinity_form == FORM1_AFFINITY) {
 		initialize_form1_numa_distance(node);
 		return;
 	}
+
+	/* FORM2 affinity  */
+	nid = of_node_to_nid_single(node);
+	if (nid == NUMA_NO_NODE)
+		return;
+
+	/*
+	 * With FORM2 we expect NUMA distance of all possible NUMA
+	 * nodes to be provided during boot.
+	 */
+	WARN(numa_distance_table[nid][nid] == -1,
+	     "NUMA distance details for node %d not provided\n", nid);
+}
+
+/*
+ * ibm,numa-lookup-index-table= {N, domainid1, domainid2, ..... domainidN}
+ * ibm,numa-distance-table = { N, 1, 2, 4, 5, 1, 6, .... N elements}
+ */
+static void initialize_form2_numa_distance_lookup_table(void)
+{
+	int i, j;
+	struct device_node *root;
+	const __u8 *numa_dist_table;
+	const __be32 *numa_lookup_index;
+	int numa_dist_table_length;
+	int max_numa_index, distance_index;
+
+	if (firmware_has_feature(FW_FEATURE_OPAL))
+		root = of_find_node_by_path("/ibm,opal");
+	else
+		root = of_find_node_by_path("/rtas");
+	if (!root)
+		root = of_find_node_by_path("/");
+
+	numa_lookup_index = of_get_property(root, "ibm,numa-lookup-index-table", NULL);
+	max_numa_index = of_read_number(&numa_lookup_index[0], 1);
+
+	/* first element of the array is the size and is encode-int */
+	numa_dist_table = of_get_property(root, "ibm,numa-distance-table", NULL);
+	numa_dist_table_length = of_read_number((const __be32 *)&numa_dist_table[0], 1);
+	/* Skip the size which is encoded int */
+	numa_dist_table += sizeof(__be32);
+
+	pr_debug("numa_dist_table_len = %d, numa_dist_indexes_len = %d\n",
+		 numa_dist_table_length, max_numa_index);
+
+	for (i = 0; i < max_numa_index; i++)
+		/* +1 skip the max_numa_index in the property */
+		numa_id_index_table[i] = of_read_number(&numa_lookup_index[i + 1], 1);
+
+
+	if (numa_dist_table_length != max_numa_index * max_numa_index) {
+
+		WARN(1, "Wrong NUMA distance information\n");
+		/* consider everybody else just remote. */
+		for (i = 0;  i < max_numa_index; i++) {
+			for (j = 0; j < max_numa_index; j++) {
+				int nodeA = numa_id_index_table[i];
+				int nodeB = numa_id_index_table[j];
+
+				if (nodeA == nodeB)
+					numa_distance_table[nodeA][nodeB] = LOCAL_DISTANCE;
+				else
+					numa_distance_table[nodeA][nodeB] = REMOTE_DISTANCE;
+			}
+		}
+	}
+
+	distance_index = 0;
+	for (i = 0;  i < max_numa_index; i++) {
+		for (j = 0; j < max_numa_index; j++) {
+			int nodeA = numa_id_index_table[i];
+			int nodeB = numa_id_index_table[j];
+
+			numa_distance_table[nodeA][nodeB] = numa_dist_table[distance_index++];
+			pr_debug("dist[%d][%d]=%d ", nodeA, nodeB, numa_distance_table[nodeA][nodeB]);
+		}
+	}
+	of_node_put(root);
 }
 
 static int __init find_primary_domain_index(void)
@@ -322,6 +428,9 @@ static int __init find_primary_domain_index(void)
 	 */
 	if (firmware_has_feature(FW_FEATURE_OPAL)) {
 		affinity_form = FORM1_AFFINITY;
+	} else if (firmware_has_feature(FW_FEATURE_FORM2_AFFINITY)) {
+		dbg("Using form 2 affinity\n");
+		affinity_form = FORM2_AFFINITY;
 	} else if (firmware_has_feature(FW_FEATURE_FORM1_AFFINITY)) {
 		dbg("Using form 1 affinity\n");
 		affinity_form = FORM1_AFFINITY;
@@ -366,9 +475,12 @@ static int __init find_primary_domain_index(void)
 
 		index = of_read_number(&distance_ref_points[1], 1);
 	} else {
+		/*
+		 * Both FORM1 and FORM2 affinity find the primary domain details
+		 * at the same offset.
+		 */
 		index = of_read_number(distance_ref_points, 1);
 	}
-
 	/*
 	 * Warn and cap if the hardware supports more than
 	 * MAX_DISTANCE_REF_POINTS domains.
@@ -807,6 +919,12 @@ static int __init parse_numa_properties(void)
 
 	dbg("NUMA associativity depth for CPU/Memory: %d\n", primary_domain_index);
 
+	/*
+	 * If it is FORM2 initialize the distance table here.
+	 */
+	if (affinity_form == FORM2_AFFINITY)
+		initialize_form2_numa_distance_lookup_table();
+
 	/*
 	 * Even though we connect cpus to numa domains later in SMP
 	 * init, we need to know the node ids now. This is because
diff --git a/arch/powerpc/platforms/pseries/firmware.c b/arch/powerpc/platforms/pseries/firmware.c
index 5d4c2bc20bba..f162156b7b68 100644
--- a/arch/powerpc/platforms/pseries/firmware.c
+++ b/arch/powerpc/platforms/pseries/firmware.c
@@ -123,6 +123,7 @@ vec5_fw_features_table[] = {
 	{FW_FEATURE_PRRN,		OV5_PRRN},
 	{FW_FEATURE_DRMEM_V2,		OV5_DRMEM_V2},
 	{FW_FEATURE_DRC_INFO,		OV5_DRC_INFO},
+	{FW_FEATURE_FORM2_AFFINITY,	OV5_FORM2_AFFINITY},
 };
 
 static void __init fw_vec5_feature_init(const char *vec5, unsigned long len)
-- 
2.31.1

[PATCH v6 6/6] powerpc/pseries: Consolidate form1 distance initialization into a helper

[Aneesh Kumar K.V]

Currently, we duplicate parsing code for ibm,associativity and
ibm,associativity-lookup-arrays in the kernel. The associativity array provided
by these device tree properties are very similar and hence can use
a helper to parse the node id and numa distance details.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
---
 arch/powerpc/mm/numa.c | 83 ++++++++++++++++++++++++++----------------
 1 file changed, 51 insertions(+), 32 deletions(-)

diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index fffb3c40f595..7506251e17f2 100644
--- a/arch/powerpc/mm/numa.c
+++ b/arch/powerpc/mm/numa.c
@@ -171,19 +171,19 @@ static void unmap_cpu_from_node(unsigned long cpu)
 }
 #endif /* CONFIG_HOTPLUG_CPU || CONFIG_PPC_SPLPAR */
 
-/*
- * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA
- * info is found.
- */
-static int associativity_to_nid(const __be32 *associativity)
+static int __associativity_to_nid(const __be32 *associativity,
+				  int max_array_sz)
 {
 	int nid = NUMA_NO_NODE;
+	/*
+	 * primary_domain_index is 1 based array index.
+	 */
+	int index = primary_domain_index  - 1;
 
-	if (!numa_enabled)
+	if (!numa_enabled || index >= max_array_sz)
 		goto out;
 
-	if (of_read_number(associativity, 1) >= primary_domain_index)
-		nid = of_read_number(&associativity[primary_domain_index], 1);
+	nid = of_read_number(&associativity[index], 1);
 
 	/* POWER4 LPAR uses 0xffff as invalid node */
 	if (nid == 0xffff || nid >= nr_node_ids)
@@ -191,6 +191,17 @@ static int associativity_to_nid(const __be32 *associativity)
 out:
 	return nid;
 }
+/*
+ * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA
+ * info is found.
+ */
+static int associativity_to_nid(const __be32 *associativity)
+{
+	int array_sz = of_read_number(associativity, 1);
+
+	/* Skip the first element in the associativity array */
+	return __associativity_to_nid((associativity + 1), array_sz);
+}
 
 static int __cpu_form2_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
 {
@@ -295,24 +306,41 @@ int of_node_to_nid(struct device_node *device)
 }
 EXPORT_SYMBOL(of_node_to_nid);
 
-static void __initialize_form1_numa_distance(const __be32 *associativity)
+static void ___initialize_form1_numa_distance(const __be32 *associativity,
+					     int max_array_sz)
 {
 	int i, nid;
 
 	if (affinity_form != FORM1_AFFINITY)
 		return;
 
-	nid = associativity_to_nid(associativity);
+	nid = __associativity_to_nid(associativity, max_array_sz);
 	if (nid != NUMA_NO_NODE) {
 		for (i = 0; i < distance_ref_points_depth; i++) {
 			const __be32 *entry;
+			int index = be32_to_cpu(distance_ref_points[i]) - 1;
+
+			/*
+			 * broken hierarchy, return with broken distance table
+			 */
+			if (index >= max_array_sz)
+				return;
 
-			entry = &associativity[be32_to_cpu(distance_ref_points[i])];
+			entry = &associativity[index];
 			distance_lookup_table[nid][i] = of_read_number(entry, 1);
 		}
 	}
 }
 
+static void __initialize_form1_numa_distance(const __be32 *associativity)
+{
+	int array_sz;
+
+	array_sz = of_read_number(associativity, 1);
+	/* Skip the first element in the associativity array */
+	___initialize_form1_numa_distance(associativity + 1, array_sz);
+}
+
 static void initialize_form1_numa_distance(struct device_node *node)
 {
 	const __be32 *associativity;
@@ -586,27 +614,18 @@ static int get_nid_and_numa_distance(struct drmem_lmb *lmb)
 
 	if (primary_domain_index <= aa.array_sz &&
 	    !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) {
-		index = lmb->aa_index * aa.array_sz + primary_domain_index - 1;
-		nid = of_read_number(&aa.arrays[index], 1);
+		const __be32 *associativity;
 
-		if (nid == 0xffff || nid >= nr_node_ids)
-			nid = default_nid;
+		index = lmb->aa_index * aa.array_sz;
+		associativity = &aa.arrays[index];
+		nid = __associativity_to_nid(associativity, aa.array_sz);
 		if (nid > 0 && affinity_form == FORM1_AFFINITY) {
-			int i;
-			const __be32 *associativity;
-
-			index = lmb->aa_index * aa.array_sz;
-			associativity = &aa.arrays[index];
 			/*
-			 * lookup array associativity entries have different format
-			 * There is no length of the array as the first element.
+			 * lookup array associativity entries have
+			 * no length of the array as the first element.
 			 */
-			for (i = 0; i < distance_ref_points_depth; i++) {
-				const __be32 *entry;
-
-				entry = &associativity[be32_to_cpu(distance_ref_points[i]) - 1];
-				distance_lookup_table[nid][i] = of_read_number(entry, 1);
-			}
+			___initialize_form1_numa_distance(associativity,
+							  aa.array_sz);
 		}
 	}
 	return nid;
@@ -632,11 +651,11 @@ int of_drconf_to_nid_single(struct drmem_lmb *lmb)
 
 	if (primary_domain_index <= aa.array_sz &&
 	    !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) {
-		index = lmb->aa_index * aa.array_sz + primary_domain_index - 1;
-		nid = of_read_number(&aa.arrays[index], 1);
+		const __be32 *associativity;
 
-		if (nid == 0xffff || nid >= nr_node_ids)
-			nid = default_nid;
+		index = lmb->aa_index * aa.array_sz;
+		associativity = &aa.arrays[index];
+		nid = __associativity_to_nid(associativity, aa.array_sz);
 	}
 	return nid;
 }
-- 
2.31.1

Re: [PATCH v6 3/6] powerpc/pseries: Consolidate different NUMA distance update code paths

[David Gibson]

[-- Attachment #1: Type: text/plain, Size: 11361 bytes --]

On Tue, Jul 27, 2021 at 03:33:08PM +0530, Aneesh Kumar K.V wrote:
> The associativity details of the newly added resourced are collected from
> the hypervisor via "ibm,configure-connector" rtas call. Update the numa
> distance details of the newly added numa node after the above call.
> 
> Instead of updating NUMA distance every time we lookup a node id
> from the associativity property, add helpers that can be used
> during boot which does this only once. Also remove the distance
> update from node id lookup helpers.
> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> ---
>  arch/powerpc/include/asm/topology.h           |   2 +
>  arch/powerpc/mm/numa.c                        | 178 +++++++++++++-----
>  arch/powerpc/platforms/pseries/hotplug-cpu.c  |   2 +
>  .../platforms/pseries/hotplug-memory.c        |   2 +
>  4 files changed, 138 insertions(+), 46 deletions(-)
> 
> diff --git a/arch/powerpc/include/asm/topology.h b/arch/powerpc/include/asm/topology.h
> index e4db64c0e184..a6425a70c37b 100644
> --- a/arch/powerpc/include/asm/topology.h
> +++ b/arch/powerpc/include/asm/topology.h
> @@ -64,6 +64,7 @@ static inline int early_cpu_to_node(int cpu)
>  }
>  
>  int of_drconf_to_nid_single(struct drmem_lmb *lmb);
> +void update_numa_distance(struct device_node *node);
>  
>  #else
>  
> @@ -93,6 +94,7 @@ static inline int of_drconf_to_nid_single(struct drmem_lmb *lmb)
>  	return first_online_node;
>  }
>  
> +static inline void update_numa_distance(struct device_node *node) {}
>  #endif /* CONFIG_NUMA */
>  
>  #if defined(CONFIG_NUMA) && defined(CONFIG_PPC_SPLPAR)
> diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
> index 368719b14dcc..c695faf67d68 100644
> --- a/arch/powerpc/mm/numa.c
> +++ b/arch/powerpc/mm/numa.c
> @@ -208,22 +208,6 @@ int __node_distance(int a, int b)
>  }
>  EXPORT_SYMBOL(__node_distance);
>  
> -static void initialize_distance_lookup_table(int nid,
> -		const __be32 *associativity)
> -{
> -	int i;
> -
> -	if (affinity_form != FORM1_AFFINITY)
> -		return;
> -
> -	for (i = 0; i < distance_ref_points_depth; i++) {
> -		const __be32 *entry;
> -
> -		entry = &associativity[be32_to_cpu(distance_ref_points[i]) - 1];
> -		distance_lookup_table[nid][i] = of_read_number(entry, 1);
> -	}
> -}
> -
>  /*
>   * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA
>   * info is found.
> @@ -241,15 +225,6 @@ static int associativity_to_nid(const __be32 *associativity)
>  	/* POWER4 LPAR uses 0xffff as invalid node */
>  	if (nid == 0xffff || nid >= nr_node_ids)
>  		nid = NUMA_NO_NODE;
> -
> -	if (nid > 0 &&
> -		of_read_number(associativity, 1) >= distance_ref_points_depth) {
> -		/*
> -		 * Skip the length field and send start of associativity array
> -		 */
> -		initialize_distance_lookup_table(nid, associativity + 1);
> -	}
> -
>  out:
>  	return nid;
>  }
> @@ -287,6 +262,48 @@ int of_node_to_nid(struct device_node *device)
>  }
>  EXPORT_SYMBOL(of_node_to_nid);
>  
> +static void __initialize_form1_numa_distance(const __be32 *associativity)
> +{
> +	int i, nid;
> +
> +	if (affinity_form != FORM1_AFFINITY)
> +		return;
> +
> +	nid = associativity_to_nid(associativity);
> +	if (nid != NUMA_NO_NODE) {
> +		for (i = 0; i < distance_ref_points_depth; i++) {
> +			const __be32 *entry;
> +
> +			entry = &associativity[be32_to_cpu(distance_ref_points[i])];
> +			distance_lookup_table[nid][i] = of_read_number(entry, 1);

So, in the conversion from the old initialize_distance_lookup_table()
you change this from accepting a bare associativity list, to requiring
the length on the front.  [*]

> +		}
> +	}
> +}
> +
> +static void initialize_form1_numa_distance(struct device_node *node)
> +{
> +	const __be32 *associativity;
> +
> +	associativity = of_get_associativity(node);
> +	if (!associativity)
> +		return;
> +
> +	__initialize_form1_numa_distance(associativity);
> +}
> +
> +/*
> + * Used to update distance information w.r.t newly added node.
> + */
> +void update_numa_distance(struct device_node *node)
> +{
> +	if (affinity_form == FORM0_AFFINITY)
> +		return;
> +	else if (affinity_form == FORM1_AFFINITY) {
> +		initialize_form1_numa_distance(node);
> +		return;
> +	}
> +}
> +
>  static int __init find_primary_domain_index(void)
>  {
>  	int index;
> @@ -433,6 +450,48 @@ static int of_get_assoc_arrays(struct assoc_arrays *aa)
>  	return 0;
>  }
>  
> +static int get_nid_and_numa_distance(struct drmem_lmb *lmb)
> +{
> +	struct assoc_arrays aa = { .arrays = NULL };
> +	int default_nid = NUMA_NO_NODE;

You never change default_nid, so it seems like it would be clearer to
get rid of this and just use NUMA_NO_NODE inline everywhere below.

> +	int nid = default_nid;
> +	int rc, index;
> +
> +	if ((primary_domain_index < 0) || !numa_enabled)
> +		return default_nid;
> +
> +	rc = of_get_assoc_arrays(&aa);
> +	if (rc)
> +		return default_nid;
> +
> +	if (primary_domain_index <= aa.array_sz &&
> +	    !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) {
> +		index = lmb->aa_index * aa.array_sz + primary_domain_index - 1;
> +		nid = of_read_number(&aa.arrays[index], 1);
> +
> +		if (nid == 0xffff || nid >= nr_node_ids)
> +			nid = default_nid;
> +		if (nid > 0 && affinity_form == FORM1_AFFINITY) {

Is the nid > 0 test assuming something about what are and aren't valid
nids?  Should it be nid != NUMA_NO_NODE instead?

> +			int i;
> +			const __be32 *associativity;
> +
> +			index = lmb->aa_index * aa.array_sz;
> +			associativity = &aa.arrays[index];

Again, you can reuse form1_numa_distance() here if it weren't for the
fact that you broke it at [*] above to no longer accept bare
associativity lists.

> +			/*
> +			 * lookup array associativity entries have different format
> +			 * There is no length of the array as the first element.
> +			 */
> +			for (i = 0; i < distance_ref_points_depth; i++) {
> +				const __be32 *entry;
> +
> +				entry = &associativity[be32_to_cpu(distance_ref_points[i]) - 1];
> +				distance_lookup_table[nid][i] = of_read_number(entry, 1);
> +			}
> +		}
> +	}
> +	return nid;
> +}
> +
>  /*
>   * This is like of_node_to_nid_single() for memory represented in the
>   * ibm,dynamic-reconfiguration-memory node.
> @@ -458,21 +517,14 @@ int of_drconf_to_nid_single(struct drmem_lmb *lmb)
>  
>  		if (nid == 0xffff || nid >= nr_node_ids)
>  			nid = default_nid;
> -
> -		if (nid > 0) {
> -			index = lmb->aa_index * aa.array_sz;
> -			initialize_distance_lookup_table(nid,
> -							&aa.arrays[index]);
> -		}
>  	}
> -
>  	return nid;
>  }
>  
>  #ifdef CONFIG_PPC_SPLPAR
> -static int vphn_get_nid(long lcpu)
> +
> +static int __vphn_get_associativity(long lcpu, __be32 *associativity)
>  {
> -	__be32 associativity[VPHN_ASSOC_BUFSIZE] = {0};
>  	long rc, hwid;
>  
>  	/*
> @@ -492,12 +544,30 @@ static int vphn_get_nid(long lcpu)
>  
>  		rc = hcall_vphn(hwid, VPHN_FLAG_VCPU, associativity);
>  		if (rc == H_SUCCESS)
> -			return associativity_to_nid(associativity);
> +			return 0;
>  	}
>  
> +	return -1;
> +}
> +
> +static int vphn_get_nid(long lcpu)
> +{
> +	__be32 associativity[VPHN_ASSOC_BUFSIZE] = {0};
> +
> +
> +	if (!__vphn_get_associativity(lcpu, associativity))
> +		return associativity_to_nid(associativity);
> +
>  	return NUMA_NO_NODE;
> +
>  }
>  #else
> +
> +static int __vphn_get_associativity(long lcpu, __be32 *associativity)
> +{
> +	return -1;
> +}
> +
>  static int vphn_get_nid(long unused)
>  {
>  	return NUMA_NO_NODE;
> @@ -692,7 +762,7 @@ static int __init numa_setup_drmem_lmb(struct drmem_lmb *lmb,
>  			size = read_n_cells(n_mem_size_cells, usm);
>  		}
>  
> -		nid = of_drconf_to_nid_single(lmb);
> +		nid = get_nid_and_numa_distance(lmb);
>  		fake_numa_create_new_node(((base + size) >> PAGE_SHIFT),
>  					  &nid);
>  		node_set_online(nid);
> @@ -709,6 +779,7 @@ static int __init parse_numa_properties(void)
>  	struct device_node *memory;
>  	int default_nid = 0;
>  	unsigned long i;
> +	const __be32 *associativity;
>  
>  	if (numa_enabled == 0) {
>  		printk(KERN_WARNING "NUMA disabled by user\n");
> @@ -734,18 +805,30 @@ static int __init parse_numa_properties(void)
>  	 * each node to be onlined must have NODE_DATA etc backing it.
>  	 */
>  	for_each_present_cpu(i) {
> +		__be32 vphn_assoc[VPHN_ASSOC_BUFSIZE];
>  		struct device_node *cpu;
> -		int nid = vphn_get_nid(i);
> +		int nid = NUMA_NO_NODE;
>  
> -		/*
> -		 * Don't fall back to default_nid yet -- we will plug
> -		 * cpus into nodes once the memory scan has discovered
> -		 * the topology.
> -		 */
> -		if (nid == NUMA_NO_NODE) {
> +		memset(vphn_assoc, 0, VPHN_ASSOC_BUFSIZE * sizeof(__be32));
> +
> +		if (__vphn_get_associativity(i, vphn_assoc) == 0) {
> +			nid = associativity_to_nid(vphn_assoc);
> +			__initialize_form1_numa_distance(vphn_assoc);
> +		} else {
> +
> +			/*
> +			 * Don't fall back to default_nid yet -- we will plug
> +			 * cpus into nodes once the memory scan has discovered
> +			 * the topology.
> +			 */
>  			cpu = of_get_cpu_node(i, NULL);
>  			BUG_ON(!cpu);
> -			nid = of_node_to_nid_single(cpu);
> +
> +			associativity = of_get_associativity(cpu);
> +			if (associativity) {
> +				nid = associativity_to_nid(associativity);
> +				__initialize_form1_numa_distance(associativity);
> +			}
>  			of_node_put(cpu);
>  		}
>  
> @@ -781,8 +864,11 @@ static int __init parse_numa_properties(void)
>  		 * have associativity properties.  If none, then
>  		 * everything goes to default_nid.
>  		 */
> -		nid = of_node_to_nid_single(memory);
> -		if (nid < 0)
> +		associativity = of_get_associativity(memory);
> +		if (associativity) {
> +			nid = associativity_to_nid(associativity);
> +			__initialize_form1_numa_distance(associativity);
> +		} else
>  			nid = default_nid;
>  
>  		fake_numa_create_new_node(((start + size) >> PAGE_SHIFT), &nid);
> diff --git a/arch/powerpc/platforms/pseries/hotplug-cpu.c b/arch/powerpc/platforms/pseries/hotplug-cpu.c
> index 7e970f81d8ff..778b6ab35f0d 100644
> --- a/arch/powerpc/platforms/pseries/hotplug-cpu.c
> +++ b/arch/powerpc/platforms/pseries/hotplug-cpu.c
> @@ -498,6 +498,8 @@ static ssize_t dlpar_cpu_add(u32 drc_index)
>  		return saved_rc;
>  	}
>  
> +	update_numa_distance(dn);
> +
>  	rc = dlpar_online_cpu(dn);
>  	if (rc) {
>  		saved_rc = rc;
> diff --git a/arch/powerpc/platforms/pseries/hotplug-memory.c b/arch/powerpc/platforms/pseries/hotplug-memory.c
> index 377d852f5a9a..ee1d81d7e54a 100644
> --- a/arch/powerpc/platforms/pseries/hotplug-memory.c
> +++ b/arch/powerpc/platforms/pseries/hotplug-memory.c
> @@ -180,6 +180,8 @@ static int update_lmb_associativity_index(struct drmem_lmb *lmb)
>  		return -ENODEV;
>  	}
>  
> +	update_numa_distance(lmb_node);
> +
>  	dr_node = of_find_node_by_path("/ibm,dynamic-reconfiguration-memory");
>  	if (!dr_node) {
>  		dlpar_free_cc_nodes(lmb_node);

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

Re: [PATCH v6 6/6] powerpc/pseries: Consolidate form1 distance initialization into a helper

[David Gibson]

[-- Attachment #1: Type: text/plain, Size: 6190 bytes --]

On Tue, Jul 27, 2021 at 03:33:11PM +0530, Aneesh Kumar K.V wrote:
> Currently, we duplicate parsing code for ibm,associativity and
> ibm,associativity-lookup-arrays in the kernel. The associativity array provided
> by these device tree properties are very similar and hence can use
> a helper to parse the node id and numa distance details.

Oh... sorry.. comments on the earlier patch were from before I read
and saw you adjusted things here.

> 
> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> ---
>  arch/powerpc/mm/numa.c | 83 ++++++++++++++++++++++++++----------------
>  1 file changed, 51 insertions(+), 32 deletions(-)
> 
> diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
> index fffb3c40f595..7506251e17f2 100644
> --- a/arch/powerpc/mm/numa.c
> +++ b/arch/powerpc/mm/numa.c
> @@ -171,19 +171,19 @@ static void unmap_cpu_from_node(unsigned long cpu)
>  }
>  #endif /* CONFIG_HOTPLUG_CPU || CONFIG_PPC_SPLPAR */
>  
> -/*
> - * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA
> - * info is found.
> - */
> -static int associativity_to_nid(const __be32 *associativity)
> +static int __associativity_to_nid(const __be32 *associativity,
> +				  int max_array_sz)
>  {
>  	int nid = NUMA_NO_NODE;
> +	/*
> +	 * primary_domain_index is 1 based array index.
> +	 */
> +	int index = primary_domain_index  - 1;
>  
> -	if (!numa_enabled)
> +	if (!numa_enabled || index >= max_array_sz)
>  		goto out;

You don't need a goto, you can just return NUMA_NO_NODE.

>  
> -	if (of_read_number(associativity, 1) >= primary_domain_index)
> -		nid = of_read_number(&associativity[primary_domain_index], 1);
> +	nid = of_read_number(&associativity[index], 1);
>  
>  	/* POWER4 LPAR uses 0xffff as invalid node */
>  	if (nid == 0xffff || nid >= nr_node_ids)
> @@ -191,6 +191,17 @@ static int associativity_to_nid(const __be32 *associativity)
>  out:
>  	return nid;
>  }
> +/*
> + * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA
> + * info is found.
> + */
> +static int associativity_to_nid(const __be32 *associativity)
> +{
> +	int array_sz = of_read_number(associativity, 1);
> +
> +	/* Skip the first element in the associativity array */
> +	return __associativity_to_nid((associativity + 1), array_sz);
> +}
>  
>  static int __cpu_form2_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
>  {
> @@ -295,24 +306,41 @@ int of_node_to_nid(struct device_node *device)
>  }
>  EXPORT_SYMBOL(of_node_to_nid);
>  
> -static void __initialize_form1_numa_distance(const __be32 *associativity)
> +static void ___initialize_form1_numa_distance(const __be32 *associativity,
> +					     int max_array_sz)
>  {
>  	int i, nid;
>  
>  	if (affinity_form != FORM1_AFFINITY)
>  		return;
>  
> -	nid = associativity_to_nid(associativity);
> +	nid = __associativity_to_nid(associativity, max_array_sz);
>  	if (nid != NUMA_NO_NODE) {
>  		for (i = 0; i < distance_ref_points_depth; i++) {
>  			const __be32 *entry;
> +			int index = be32_to_cpu(distance_ref_points[i]) - 1;
> +
> +			/*
> +			 * broken hierarchy, return with broken distance table

WARN_ON, maybe?

> +			 */
> +			if (index >= max_array_sz)
> +				return;
>  
> -			entry = &associativity[be32_to_cpu(distance_ref_points[i])];
> +			entry = &associativity[index];
>  			distance_lookup_table[nid][i] = of_read_number(entry, 1);
>  		}
>  	}
>  }
>  
> +static void __initialize_form1_numa_distance(const __be32 *associativity)

Do you actually use this in-between wrapper?

> +{
> +	int array_sz;
> +
> +	array_sz = of_read_number(associativity, 1);
> +	/* Skip the first element in the associativity array */
> +	___initialize_form1_numa_distance(associativity + 1, array_sz);
> +}
> +
>  static void initialize_form1_numa_distance(struct device_node *node)
>  {
>  	const __be32 *associativity;
> @@ -586,27 +614,18 @@ static int get_nid_and_numa_distance(struct drmem_lmb *lmb)
>  
>  	if (primary_domain_index <= aa.array_sz &&
>  	    !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) {
> -		index = lmb->aa_index * aa.array_sz + primary_domain_index - 1;
> -		nid = of_read_number(&aa.arrays[index], 1);
> +		const __be32 *associativity;
>  
> -		if (nid == 0xffff || nid >= nr_node_ids)
> -			nid = default_nid;
> +		index = lmb->aa_index * aa.array_sz;
> +		associativity = &aa.arrays[index];
> +		nid = __associativity_to_nid(associativity, aa.array_sz);
>  		if (nid > 0 && affinity_form == FORM1_AFFINITY) {
> -			int i;
> -			const __be32 *associativity;
> -
> -			index = lmb->aa_index * aa.array_sz;
> -			associativity = &aa.arrays[index];
>  			/*
> -			 * lookup array associativity entries have different format
> -			 * There is no length of the array as the first element.
> +			 * lookup array associativity entries have
> +			 * no length of the array as the first element.
>  			 */
> -			for (i = 0; i < distance_ref_points_depth; i++) {
> -				const __be32 *entry;
> -
> -				entry = &associativity[be32_to_cpu(distance_ref_points[i]) - 1];
> -				distance_lookup_table[nid][i] = of_read_number(entry, 1);
> -			}
> +			___initialize_form1_numa_distance(associativity,
> +							  aa.array_sz);

Better, thanks.

>  		}
>  	}
>  	return nid;
> @@ -632,11 +651,11 @@ int of_drconf_to_nid_single(struct drmem_lmb *lmb)
>  
>  	if (primary_domain_index <= aa.array_sz &&
>  	    !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) {
> -		index = lmb->aa_index * aa.array_sz + primary_domain_index - 1;
> -		nid = of_read_number(&aa.arrays[index], 1);
> +		const __be32 *associativity;
>  
> -		if (nid == 0xffff || nid >= nr_node_ids)
> -			nid = default_nid;
> +		index = lmb->aa_index * aa.array_sz;
> +		associativity = &aa.arrays[index];
> +		nid = __associativity_to_nid(associativity, aa.array_sz);
>  	}
>  	return nid;
>  }

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]

Re: [PATCH v6 6/6] powerpc/pseries: Consolidate form1 distance initialization into a helper

[Aneesh Kumar K.V]

On 8/6/21 12:17 PM, David Gibson wrote:
> On Tue, Jul 27, 2021 at 03:33:11PM +0530, Aneesh Kumar K.V wrote:
>> Currently, we duplicate parsing code for ibm,associativity and
>> ibm,associativity-lookup-arrays in the kernel. The associativity array provided
>> by these device tree properties are very similar and hence can use
>> a helper to parse the node id and numa distance details.
> 
> Oh... sorry.. comments on the earlier patch were from before I read
> and saw you adjusted things here.
> 
>>
>> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
>> ---
>>   arch/powerpc/mm/numa.c | 83 ++++++++++++++++++++++++++----------------
>>   1 file changed, 51 insertions(+), 32 deletions(-)
>>
>> diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
>> index fffb3c40f595..7506251e17f2 100644
>> --- a/arch/powerpc/mm/numa.c
>> +++ b/arch/powerpc/mm/numa.c
>> @@ -171,19 +171,19 @@ static void unmap_cpu_from_node(unsigned long cpu)
>>   }
>>   #endif /* CONFIG_HOTPLUG_CPU || CONFIG_PPC_SPLPAR */
>>   
>> -/*
>> - * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA
>> - * info is found.
>> - */
>> -static int associativity_to_nid(const __be32 *associativity)
>> +static int __associativity_to_nid(const __be32 *associativity,
>> +				  int max_array_sz)
>>   {
>>   	int nid = NUMA_NO_NODE;
>> +	/*
>> +	 * primary_domain_index is 1 based array index.
>> +	 */
>> +	int index = primary_domain_index  - 1;
>>   
>> -	if (!numa_enabled)
>> +	if (!numa_enabled || index >= max_array_sz)
>>   		goto out;
> 
> You don't need a goto, you can just return NUMA_NO_NODE.

updated

> 
>>   
>> -	if (of_read_number(associativity, 1) >= primary_domain_index)
>> -		nid = of_read_number(&associativity[primary_domain_index], 1);
>> +	nid = of_read_number(&associativity[index], 1);
>>   
>>   	/* POWER4 LPAR uses 0xffff as invalid node */
>>   	if (nid == 0xffff || nid >= nr_node_ids)
>> @@ -191,6 +191,17 @@ static int associativity_to_nid(const __be32 *associativity)
>>   out:
>>   	return nid;
>>   }
>> +/*
>> + * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA
>> + * info is found.
>> + */
>> +static int associativity_to_nid(const __be32 *associativity)
>> +{
>> +	int array_sz = of_read_number(associativity, 1);
>> +
>> +	/* Skip the first element in the associativity array */
>> +	return __associativity_to_nid((associativity + 1), array_sz);
>> +}
>>   
>>   static int __cpu_form2_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
>>   {
>> @@ -295,24 +306,41 @@ int of_node_to_nid(struct device_node *device)
>>   }
>>   EXPORT_SYMBOL(of_node_to_nid);
>>   
>> -static void __initialize_form1_numa_distance(const __be32 *associativity)
>> +static void ___initialize_form1_numa_distance(const __be32 *associativity,
>> +					     int max_array_sz)
>>   {
>>   	int i, nid;
>>   
>>   	if (affinity_form != FORM1_AFFINITY)
>>   		return;
>>   
>> -	nid = associativity_to_nid(associativity);
>> +	nid = __associativity_to_nid(associativity, max_array_sz);
>>   	if (nid != NUMA_NO_NODE) {
>>   		for (i = 0; i < distance_ref_points_depth; i++) {
>>   			const __be32 *entry;
>> +			int index = be32_to_cpu(distance_ref_points[i]) - 1;
>> +
>> +			/*
>> +			 * broken hierarchy, return with broken distance table
> 
> WARN_ON, maybe?


updated

> 
>> +			 */
>> +			if (index >= max_array_sz)
>> +				return;
>>   
>> -			entry = &associativity[be32_to_cpu(distance_ref_points[i])];
>> +			entry = &associativity[index];
>>   			distance_lookup_table[nid][i] = of_read_number(entry, 1);
>>   		}
>>   	}
>>   }
>>   
>> +static void __initialize_form1_numa_distance(const __be32 *associativity)
> 
> Do you actually use this in-between wrapper?

yes used in

static void initialize_form1_numa_distance(struct device_node *node)
{
	const __be32 *associativity;

	associativity = of_get_associativity(node);
	if (!associativity)
		return;

	__initialize_form1_numa_distance(associativity);
}



> 
>> +{
>> +	int array_sz;
>> +
>> +	array_sz = of_read_number(associativity, 1);
>> +	/* Skip the first element in the associativity array */
>> +	___initialize_form1_numa_distance(associativity + 1, array_sz);
>> +}
>> +
>>   static void initialize_form1_numa_distance(struct device_node *node)
>>   {
>>   	const __be32 *associativity;
>> @@ -586,27 +614,18 @@ static int get_nid_and_numa_distance(struct drmem_lmb *lmb)
>>   
>>   	if (primary_domain_index <= aa.array_sz &&
>>   	    !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) {
>> -		index = lmb->aa_index * aa.array_sz + primary_domain_index - 1;
>> -		nid = of_read_number(&aa.arrays[index], 1);
>> +		const __be32 *associativity;
>>   
>> -		if (nid == 0xffff || nid >= nr_node_ids)
>> -			nid = default_nid;
>> +		index = lmb->aa_index * aa.array_sz;
>> +		associativity = &aa.arrays[index];
>> +		nid = __associativity_to_nid(associativity, aa.array_sz);
>>   		if (nid > 0 && affinity_form == FORM1_AFFINITY) {
>> -			int i;
>> -			const __be32 *associativity;
>> -
>> -			index = lmb->aa_index * aa.array_sz;
>> -			associativity = &aa.arrays[index];
>>   			/*
>> -			 * lookup array associativity entries have different format
>> -			 * There is no length of the array as the first element.
>> +			 * lookup array associativity entries have
>> +			 * no length of the array as the first element.
>>   			 */
>> -			for (i = 0; i < distance_ref_points_depth; i++) {
>> -				const __be32 *entry;
>> -
>> -				entry = &associativity[be32_to_cpu(distance_ref_points[i]) - 1];
>> -				distance_lookup_table[nid][i] = of_read_number(entry, 1);
>> -			}
>> +			___initialize_form1_numa_distance(associativity,
>> +							  aa.array_sz);
> 
> Better, thanks.
> 
>>   		}
>>   	}
>>   	return nid;
>> @@ -632,11 +651,11 @@ int of_drconf_to_nid_single(struct drmem_lmb *lmb)
>>   
>>   	if (primary_domain_index <= aa.array_sz &&
>>   	    !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) {
>> -		index = lmb->aa_index * aa.array_sz + primary_domain_index - 1;
>> -		nid = of_read_number(&aa.arrays[index], 1);
>> +		const __be32 *associativity;
>>   
>> -		if (nid == 0xffff || nid >= nr_node_ids)
>> -			nid = default_nid;
>> +		index = lmb->aa_index * aa.array_sz;
>> +		associativity = &aa.arrays[index];
>> +		nid = __associativity_to_nid(associativity, aa.array_sz);
>>   	}
>>   	return nid;
>>   }
> 


-aneesh

Re: [PATCH v6 6/6] powerpc/pseries: Consolidate form1 distance initialization into a helper

[David Gibson]

[-- Attachment #1: Type: text/plain, Size: 7396 bytes --]

On Fri, Aug 06, 2021 at 09:53:59PM +0530, Aneesh Kumar K.V wrote:
> On 8/6/21 12:17 PM, David Gibson wrote:
> > On Tue, Jul 27, 2021 at 03:33:11PM +0530, Aneesh Kumar K.V wrote:
> > > Currently, we duplicate parsing code for ibm,associativity and
> > > ibm,associativity-lookup-arrays in the kernel. The associativity array provided
> > > by these device tree properties are very similar and hence can use
> > > a helper to parse the node id and numa distance details.
> > 
> > Oh... sorry.. comments on the earlier patch were from before I read
> > and saw you adjusted things here.
> > 
> > > 
> > > Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
> > > ---
> > >   arch/powerpc/mm/numa.c | 83 ++++++++++++++++++++++++++----------------
> > >   1 file changed, 51 insertions(+), 32 deletions(-)
> > > 
> > > diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
> > > index fffb3c40f595..7506251e17f2 100644
> > > --- a/arch/powerpc/mm/numa.c
> > > +++ b/arch/powerpc/mm/numa.c
> > > @@ -171,19 +171,19 @@ static void unmap_cpu_from_node(unsigned long cpu)
> > >   }
> > >   #endif /* CONFIG_HOTPLUG_CPU || CONFIG_PPC_SPLPAR */
> > > -/*
> > > - * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA
> > > - * info is found.
> > > - */
> > > -static int associativity_to_nid(const __be32 *associativity)
> > > +static int __associativity_to_nid(const __be32 *associativity,
> > > +				  int max_array_sz)
> > >   {
> > >   	int nid = NUMA_NO_NODE;
> > > +	/*
> > > +	 * primary_domain_index is 1 based array index.
> > > +	 */
> > > +	int index = primary_domain_index  - 1;
> > > -	if (!numa_enabled)
> > > +	if (!numa_enabled || index >= max_array_sz)
> > >   		goto out;
> > 
> > You don't need a goto, you can just return NUMA_NO_NODE.
> 
> updated
> 
> > 
> > > -	if (of_read_number(associativity, 1) >= primary_domain_index)
> > > -		nid = of_read_number(&associativity[primary_domain_index], 1);
> > > +	nid = of_read_number(&associativity[index], 1);
> > >   	/* POWER4 LPAR uses 0xffff as invalid node */
> > >   	if (nid == 0xffff || nid >= nr_node_ids)
> > > @@ -191,6 +191,17 @@ static int associativity_to_nid(const __be32 *associativity)
> > >   out:
> > >   	return nid;
> > >   }
> > > +/*
> > > + * Returns nid in the range [0..nr_node_ids], or -1 if no useful NUMA
> > > + * info is found.
> > > + */
> > > +static int associativity_to_nid(const __be32 *associativity)
> > > +{
> > > +	int array_sz = of_read_number(associativity, 1);
> > > +
> > > +	/* Skip the first element in the associativity array */
> > > +	return __associativity_to_nid((associativity + 1), array_sz);
> > > +}
> > >   static int __cpu_form2_relative_distance(__be32 *cpu1_assoc, __be32 *cpu2_assoc)
> > >   {
> > > @@ -295,24 +306,41 @@ int of_node_to_nid(struct device_node *device)
> > >   }
> > >   EXPORT_SYMBOL(of_node_to_nid);
> > > -static void __initialize_form1_numa_distance(const __be32 *associativity)
> > > +static void ___initialize_form1_numa_distance(const __be32 *associativity,
> > > +					     int max_array_sz)
> > >   {
> > >   	int i, nid;
> > >   	if (affinity_form != FORM1_AFFINITY)
> > >   		return;
> > > -	nid = associativity_to_nid(associativity);
> > > +	nid = __associativity_to_nid(associativity, max_array_sz);
> > >   	if (nid != NUMA_NO_NODE) {
> > >   		for (i = 0; i < distance_ref_points_depth; i++) {
> > >   			const __be32 *entry;
> > > +			int index = be32_to_cpu(distance_ref_points[i]) - 1;
> > > +
> > > +			/*
> > > +			 * broken hierarchy, return with broken distance table
> > 
> > WARN_ON, maybe?
> 
> 
> updated
> 
> > 
> > > +			 */
> > > +			if (index >= max_array_sz)
> > > +				return;
> > > -			entry = &associativity[be32_to_cpu(distance_ref_points[i])];
> > > +			entry = &associativity[index];
> > >   			distance_lookup_table[nid][i] = of_read_number(entry, 1);
> > >   		}
> > >   	}
> > >   }
> > > +static void __initialize_form1_numa_distance(const __be32 *associativity)
> > 
> > Do you actually use this in-between wrapper?
> 
> yes used in
> 
> static void initialize_form1_numa_distance(struct device_node *node)
> {
> 	const __be32 *associativity;
> 
> 	associativity = of_get_associativity(node);
> 	if (!associativity)
> 		return;
> 
> 	__initialize_form1_numa_distance(associativity);

Right, but I mean in more than one place.  If this is the only user,
you might as well expand it inline here.

> }
> 
> 
> 
> > 
> > > +{
> > > +	int array_sz;
> > > +
> > > +	array_sz = of_read_number(associativity, 1);
> > > +	/* Skip the first element in the associativity array */
> > > +	___initialize_form1_numa_distance(associativity + 1, array_sz);
> > > +}
> > > +
> > >   static void initialize_form1_numa_distance(struct device_node *node)
> > >   {
> > >   	const __be32 *associativity;
> > > @@ -586,27 +614,18 @@ static int get_nid_and_numa_distance(struct drmem_lmb *lmb)
> > >   	if (primary_domain_index <= aa.array_sz &&
> > >   	    !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) {
> > > -		index = lmb->aa_index * aa.array_sz + primary_domain_index - 1;
> > > -		nid = of_read_number(&aa.arrays[index], 1);
> > > +		const __be32 *associativity;
> > > -		if (nid == 0xffff || nid >= nr_node_ids)
> > > -			nid = default_nid;
> > > +		index = lmb->aa_index * aa.array_sz;
> > > +		associativity = &aa.arrays[index];
> > > +		nid = __associativity_to_nid(associativity, aa.array_sz);
> > >   		if (nid > 0 && affinity_form == FORM1_AFFINITY) {
> > > -			int i;
> > > -			const __be32 *associativity;
> > > -
> > > -			index = lmb->aa_index * aa.array_sz;
> > > -			associativity = &aa.arrays[index];
> > >   			/*
> > > -			 * lookup array associativity entries have different format
> > > -			 * There is no length of the array as the first element.
> > > +			 * lookup array associativity entries have
> > > +			 * no length of the array as the first element.
> > >   			 */
> > > -			for (i = 0; i < distance_ref_points_depth; i++) {
> > > -				const __be32 *entry;
> > > -
> > > -				entry = &associativity[be32_to_cpu(distance_ref_points[i]) - 1];
> > > -				distance_lookup_table[nid][i] = of_read_number(entry, 1);
> > > -			}
> > > +			___initialize_form1_numa_distance(associativity,
> > > +							  aa.array_sz);
> > 
> > Better, thanks.
> > 
> > >   		}
> > >   	}
> > >   	return nid;
> > > @@ -632,11 +651,11 @@ int of_drconf_to_nid_single(struct drmem_lmb *lmb)
> > >   	if (primary_domain_index <= aa.array_sz &&
> > >   	    !(lmb->flags & DRCONF_MEM_AI_INVALID) && lmb->aa_index < aa.n_arrays) {
> > > -		index = lmb->aa_index * aa.array_sz + primary_domain_index - 1;
> > > -		nid = of_read_number(&aa.arrays[index], 1);
> > > +		const __be32 *associativity;
> > > -		if (nid == 0xffff || nid >= nr_node_ids)
> > > -			nid = default_nid;
> > > +		index = lmb->aa_index * aa.array_sz;
> > > +		associativity = &aa.arrays[index];
> > > +		nid = __associativity_to_nid(associativity, aa.array_sz);
> > >   	}
> > >   	return nid;
> > >   }
> > 
> 
> 
> -aneesh
> 

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]