Re: [PATCH 5.10 105/124] powerpc/pseries: Add support for FORM2 associativity

Hi Greg,

On Tue, Apr 18, 2023 at 02:22:04PM +0200, Greg Kroah-Hartman wrote:

From: Aneesh Kumar K.V aneesh.kumar@linux.ibm.com

[ Upstream commit 1c6b5a7e74052768977855f95d6b8812f6e7772c ]

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 Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20210812132223.225214-6-aneesh.kumar@linux.ibm.com Stable-dep-of: b277fc793daf ("powerpc/papr_scm: Update the NUMA distance table for the target node") Signed-off-by: Sasha Levin sashal@kernel.org

---

Documentation/powerpc/associativity.rst | 104 ++++++++++++ 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 | 187 ++++++++++++++++++---- arch/powerpc/platforms/pseries/firmware.c | 1 + 6 files changed, 262 insertions(+), 37 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 0000000000000..07e7dd3d6c87e --- /dev/null +++ b/Documentation/powerpc/associativity.rst @@ -0,0 +1,104 @@ +============================ +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-distace-table = <9>, /bits/ 8 < 10 20 80

• 			 20  10 160
  

• 			 80 160  10>;
  

• | 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 0cf648d829f15..89a31f1c7b118 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 df9fec9d232cb..5c80152e8f188 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 a3bf3587a4162..6f7ad80763159 100644 --- a/arch/powerpc/kernel/prom_init.c +++ b/arch/powerpc/kernel/prom_init.c @@ -1069,7 +1069,8 @@ 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 010476abec344..cfc170935a58b 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 +171,54 @@ static void unmap_cpu_from_node(unsigned long cpu) } #endif /* CONFIG_HOTPLUG_CPU || CONFIG_PPC_SPLPAR */ +static int __associativity_to_nid(const __be32 *associativity,

• 		  int max_array_sz)
  

+{

• int nid;
• /*

• * primary_domain_index is 1 based array index.
  

• */
  

• int index = primary_domain_index - 1;
• if (!numa_enabled || index >= max_array_sz)

• return NUMA_NO_NODE;
  

• nid = of_read_number(&associativity[index], 1);
• /* POWER4 LPAR uses 0xffff as invalid node */
• if (nid == 0xffff || nid >= nr_node_ids)

• nid = NUMA_NO_NODE;
  

• 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) +{

• 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 +239,9 @@ 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 +255,9 @@ 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++) { @@ -216,37 +272,6 @@ int __node_distance(int a, int b) } EXPORT_SYMBOL(__node_distance); -static int __associativity_to_nid(const __be32 *associativity,

• 		  int max_array_sz)
  

-{

• int nid;
• /*

• * primary_domain_index is 1 based array index.
  

• */
  

• int index = primary_domain_index - 1;
• if (!numa_enabled || index >= max_array_sz)

• return NUMA_NO_NODE;
  

• nid = of_read_number(&associativity[index], 1);
• /* POWER4 LPAR uses 0xffff as invalid node */
• if (nid == 0xffff || nid >= nr_node_ids)

• nid = NUMA_NO_NODE;
  

• 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);

-}

/* Returns the nid associated with the given device tree node,

• or -1 if not found.

*/ @@ -320,6 +345,8 @@ static void initialize_form1_numa_distance(const __be32 *associativity) */ void update_numa_distance(struct device_node *node) {

• int nid;
• if (affinity_form == FORM0_AFFINITY) return; else if (affinity_form == FORM1_AFFINITY) {

@@ -332,6 +359,84 @@ void update_numa_distance(struct device_node *node) initialize_form1_numa_distance(associativity); 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) @@ -344,6 +449,9 @@ 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;

@@ -388,9 +496,12 @@ 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.

@@ -819,6 +930,12 @@ 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 5d4c2bc20bbab..f162156b7b68d 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) -- 2.39.2

This commit causes documentation build to fail:

| Sphinx parallel build error: | docutils.utils.SystemMessage: /build/linux/Documentation/powerpc/associativity.rst:1: (SEVERE/4) Title overline & underline mismatch. | | ============================ | NUMA resource associativity | =============================

This in fact was fixed with upstream f50da6edbf1e ("powerpc/doc: Fix htmldocs errors") but was not applied along with the above changes.

Can you please pick f50da6edbf1e as well for 5.10.y?

#regzbot ^introduced 1c6b5a7e7405 #regzbot ^introduced 453b3188be89 #regzbot fixed-by: f50da6edbf1e

Regards, Salvatore