From 4cf04b9e75db0da2c199fa12003433b3d0427fd0 Mon Sep 17 00:00:00 2001 From: Haren Myneni Date: Sat, 16 May 2026 11:34:21 -0700 Subject: [PATCH 07/11] drmgr: Add NUMA configuration update for CPU remove Upstream: merged, expected in v1.3.15 Git-commit: 4cf04b9e75db0da2c199fa12003433b3d0427fd0 This patch adds NUMA node config update for CPU removal. Updates number of LMBs and CPUs for each node and also calculates total number of CPUs from memory less nodes. This node configuration is used to identify the node based on the node ratio from which the CPU is selected to remove Signed-off-by: Haren Myneni Reviewed-by: Dave Marquardt Signed-off-by: Tyrel Datwyler --- src/drmgr/common_numa.h | 1 + src/drmgr/drslot_chrp_cpu.c | 53 +++++++++++++++++++++++++++++++++++++ 2 files changed, 54 insertions(+) diff --git a/src/drmgr/common_numa.h b/src/drmgr/common_numa.h index 7aea026..edf4349 100644 --- a/src/drmgr/common_numa.h +++ b/src/drmgr/common_numa.h @@ -38,6 +38,7 @@ struct ppcnuma_topology { unsigned int lmb_count; unsigned int cpuless_node_count; unsigned int cpuless_lmb_count; + unsigned int memless_cpu_count; unsigned int node_count, node_min, node_max; struct ppcnuma_node *nodes[MAX_NUMNODES]; struct ppcnuma_node *ratio; diff --git a/src/drmgr/drslot_chrp_cpu.c b/src/drmgr/drslot_chrp_cpu.c index 6a21663..e367634 100644 --- a/src/drmgr/drslot_chrp_cpu.c +++ b/src/drmgr/drslot_chrp_cpu.c @@ -26,10 +26,14 @@ #include #include #include +#include #include "dr.h" #include "drcpu.h" #include "drpci.h" #include "ofdt.h" +#include "common_numa.h" + +#define DEFAULT_LMB_SIZE 0x10000000 /* 256MB */ struct cpu_operation; typedef int (cpu_op_func_t) (void); @@ -395,6 +399,43 @@ static int smt_threads_func(struct dr_info *dr_info) return rc; } +/* + * Per node CPUs are defined as part of build_numa_topology(). + * This function calculates number of LMBs per node based on + * node mememory / lmb-size. + * n_cpus and n_lmbs are used to determine node ratio. + */ +static int cpu_update_numa_config(void) +{ + struct ppcnuma_node *node; + unsigned long long node_size; + int rc, nid; + uint64_t lmb_sz; + + rc = get_dynamic_lmb_size(&lmb_sz); + /* + * Use the default value if lmb-size property is not available. + * For CPU removal, node ratio will be calculated based on + * total n_lmbs per CPU. + */ + if (rc) + lmb_sz = DEFAULT_LMB_SIZE; + + ppcnuma_foreach_node(&numa, nid, node) { + node_size = numa_node_size(nid, 0); + /* + * Node has memory + * n_lmbs = Total memory / lmb-size + */ + if (node_size) { + node->n_lmbs = node_size / lmb_sz; + } else + numa.memless_cpu_count += node->n_cpus; + } + + return 0; +} + int valid_cpu_options(void) { /* default to a quantity of 1 */ @@ -442,6 +483,15 @@ int drslot_chrp_cpu(void) return -1; } + /* + * Maintain NUMA aware hotplug only for remove and with count request. + */ + if (usr_drc_count && (usr_action == REMOVE)) { + build_numa_topology(); + if (numa_enabled) + cpu_update_numa_config(); + } + /* If a user specifies a drc name, the quantity to add/remove is * one. Enforce that here so the loops in add/remove code behave * accordingly. @@ -473,6 +523,9 @@ int drslot_chrp_cpu(void) if (usr_action == ADD || usr_action == REMOVE) run_hooks(DRC_TYPE_CPU, usr_action, HOOK_POST, count); + if ((usr_action == REMOVE) && numa_enabled) + free_numa_topology(); + free_cpu_drc_info(&dr_info); return rc; } -- 2.51.0