linux-kernel - [PATCH v2 01/10] powerpc/smp: Cache node for reuse

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Date:   Tue, 21 Jul 2020 17:08:05 +0530
From:   Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
To:     Michael Ellerman <michaele@....ibm.com>
Cc:     Srikar Dronamraju <srikar@...ux.vnet.ibm.com>,
        linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Valentin Schneider <valentin.schneider@....com>,
        Nick Piggin <npiggin@....ibm.com>,
        Oliver OHalloran <oliveroh@....ibm.com>,
        Nathan Lynch <nathanl@...ux.ibm.com>,
        Michael Neuling <mikey@...ux.ibm.com>,
        Anton Blanchard <anton@....ibm.com>,
        Gautham R Shenoy <ego@...ux.vnet.ibm.com>,
        Vaidyanathan Srinivasan <svaidy@...ux.ibm.com>,
        Jordan Niethe <jniethe5@...il.com>
Subject: [PATCH v2 01/10] powerpc/smp: Cache node for reuse

While cpu_to_node is inline function with access to per_cpu variable.
However when using repeatedly, it may be cleaner to cache it in a local
variable.

Also fix a build error in a some weird config.
"error: _numa_cpu_lookup_table_ undeclared"

No functional change

Cc: linuxppc-dev <linuxppc-dev@...ts.ozlabs.org>
Cc: LKML <linux-kernel@...r.kernel.org>
Cc: Michael Ellerman <michaele@....ibm.com>
Cc: Ingo Molnar <mingo@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Valentin Schneider <valentin.schneider@....com>
Cc: Nick Piggin <npiggin@....ibm.com>
Cc: Oliver OHalloran <oliveroh@....ibm.com>
Cc: Nathan Lynch <nathanl@...ux.ibm.com>
Cc: Michael Neuling <mikey@...ux.ibm.com>
Cc: Anton Blanchard <anton@....ibm.com>
Cc: Gautham R Shenoy <ego@...ux.vnet.ibm.com>
Cc: Vaidyanathan Srinivasan <svaidy@...ux.ibm.com>
Cc: Jordan Niethe <jniethe5@...il.com>
Reviewed-by: Gautham R. Shenoy <ego@...ux.vnet.ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
---
 arch/powerpc/kernel/smp.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 73199470c265..680c0edcc59d 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -843,7 +843,7 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 
 	DBG("smp_prepare_cpus\n");
 
-	/* 
+	/*
 	 * setup_cpu may need to be called on the boot cpu. We havent
 	 * spun any cpus up but lets be paranoid.
 	 */
@@ -854,20 +854,24 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
 	cpu_callin_map[boot_cpuid] = 1;
 
 	for_each_possible_cpu(cpu) {
+		int node = cpu_to_node(cpu);
+
 		zalloc_cpumask_var_node(&per_cpu(cpu_sibling_map, cpu),
-					GFP_KERNEL, cpu_to_node(cpu));
+					GFP_KERNEL, node);
 		zalloc_cpumask_var_node(&per_cpu(cpu_l2_cache_map, cpu),
-					GFP_KERNEL, cpu_to_node(cpu));
+					GFP_KERNEL, node);
 		zalloc_cpumask_var_node(&per_cpu(cpu_core_map, cpu),
-					GFP_KERNEL, cpu_to_node(cpu));
+					GFP_KERNEL, node);
+#ifdef CONFIG_NEED_MULTIPLE_NODES
 		/*
 		 * numa_node_id() works after this.
 		 */
 		if (cpu_present(cpu)) {
-			set_cpu_numa_node(cpu, numa_cpu_lookup_table[cpu]);
-			set_cpu_numa_mem(cpu,
-				local_memory_node(numa_cpu_lookup_table[cpu]));
+			node = numa_cpu_lookup_table[cpu];
+			set_cpu_numa_node(cpu, node);
+			set_cpu_numa_mem(cpu, local_memory_node(node));
 		}
+#endif
 	}
 
 	/* Init the cpumasks so the boot CPU is related to itself */
-- 
2.17.1