[PATCH V5 3/4] x86: Support Generic Initiator only proximity domains

From: Jonathan Cameron
Date: Fri Oct 04 2019 - 07:44:29 EST


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

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

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

diff --git a/arch/x86/include/asm/numa.h b/arch/x86/include/asm/numa.h
index bbfde3d2662f..f631467272a3 100644
--- a/arch/x86/include/asm/numa.h
+++ b/arch/x86/include/asm/numa.h
@@ -62,12 +62,14 @@ extern void numa_clear_node(int cpu);
extern void __init init_cpu_to_node(void);
extern void numa_add_cpu(int cpu);
extern void numa_remove_cpu(int cpu);
+extern void init_gi_nodes(void);
#else /* CONFIG_NUMA */
static inline void numa_set_node(int cpu, int node) { }
static inline void numa_clear_node(int cpu) { }
static inline void init_cpu_to_node(void) { }
static inline void numa_add_cpu(int cpu) { }
static inline void numa_remove_cpu(int cpu) { }
+static inline void init_gi_nodes(void) { }
#endif /* CONFIG_NUMA */

#ifdef CONFIG_DEBUG_PER_CPU_MAPS
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index cfb533d42371..b6c977907ea5 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -1264,6 +1264,7 @@ void __init setup_arch(char **cmdline_p)
prefill_possible_map();

init_cpu_to_node();
+ init_gi_nodes();

io_apic_init_mappings();

diff --git a/arch/x86/mm/numa.c b/arch/x86/mm/numa.c
index 4123100e0eaf..50bf724a425e 100644
--- a/arch/x86/mm/numa.c
+++ b/arch/x86/mm/numa.c
@@ -733,6 +733,20 @@ static void __init init_memory_less_node(int nid)
*/
}

+/*
+ * Generic Initiator Nodes may have neither CPU nor Memory.
+ * At this stage if either of the others were present we would
+ * already be online.
+ */
+void __init init_gi_nodes(void)
+{
+ int nid;
+
+ for_each_node_state(nid, N_GENERIC_INITIATOR)
+ if (!node_online(nid))
+ init_memory_less_node(nid);
+}
+
/*
* Setup early cpu_to_node.
*
--
2.20.1