Subject: [PATCH v5 02/10] powerpc/smp: Merge Power9 topology with Power topology

From: Srikar Dronamraju <[email-masked]>
Date: Mon, 10 Aug 2020 12:48:26 +0530

A new sched_domain_topology_level was added just for Power9. However the
same can be achieved by merging powerpc_topology with power9_topology
and makes the code more simpler especially when adding a new sched
domain.

Cc: linuxppc-dev <[email-masked]>
Cc: LKML <[email-masked]>
Cc: Michael Ellerman <[email-masked]>
Cc: Nicholas Piggin <[email-masked]>
Cc: Anton Blanchard <[email-masked]>
Cc: Oliver O'Halloran <[email-masked]>
Cc: Nathan Lynch <[email-masked]>
Cc: Michael Neuling <[email-masked]>
Cc: Gautham R Shenoy <[email-masked]>
Cc: Ingo Molnar <[email-masked]>
Cc: Peter Zijlstra <[email-masked]>
Cc: Valentin Schneider <[email-masked]>
Cc: Jordan Niethe <[email-masked]>
Cc: Vaidyanathan Srinivasan <[email-masked]>
Reviewed-by: Gautham R. Shenoy <[email-masked]>
Signed-off-by: Srikar Dronamraju <[email-masked]>
---
Changelog v1 -> v2:
	Replaced a reference to cpu_smt_mask with per_cpu(cpu_sibling_map, cpu)
	since cpu_smt_mask is only defined under CONFIG_SCHED_SMT

 arch/powerpc/kernel/smp.c | 25 +++----------------------
 1 file changed, 3 insertions(+), 22 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index edf94ca64eea..08da765b91f1 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1313,7 +1313,7 @@ int setup_profiling_timer(unsigned int multiplier)
 }
 
 #ifdef CONFIG_SCHED_SMT
-/* cpumask of CPUs with asymetric SMT dependancy */
+/* cpumask of CPUs with asymmetric SMT dependency */
 static int powerpc_smt_flags(void)
 {
 	int flags = SD_SHARE_CPUCAPACITY | SD_SHARE_PKG_RESOURCES;
@@ -1326,14 +1326,6 @@ static int powerpc_smt_flags(void)
 }
 #endif
 
-static struct sched_domain_topology_level powerpc_topology[] = {
-#ifdef CONFIG_SCHED_SMT
-	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
-#endif
-	{ cpu_cpu_mask, SD_INIT_NAME(DIE) },
-	{ NULL, },
-};
-
 /*
  * P9 has a slightly odd architecture where pairs of cores share an L2 cache.
  * This topology makes it *much* cheaper to migrate tasks between adjacent cores
@@ -1361,7 +1353,7 @@ static const struct cpumask *smallcore_smt_mask(int cpu)
 }
 #endif
 
-static struct sched_domain_topology_level power9_topology[] = {
+static struct sched_domain_topology_level powerpc_topology[] = {
 #ifdef CONFIG_SCHED_SMT
 	{ cpu_smt_mask, powerpc_smt_flags, SD_INIT_NAME(SMT) },
 #endif
@@ -1386,21 +1378,10 @@ void __init smp_cpus_done(unsigned int max_cpus)
 #ifdef CONFIG_SCHED_SMT
 	if (has_big_cores) {
 		pr_info("Big cores detected but using small core scheduling\n");
-		power9_topology[0].mask = smallcore_smt_mask;
 		powerpc_topology[0].mask = smallcore_smt_mask;
 	}
 #endif
-	/*
-	 * If any CPU detects that it's sharing a cache with another CPU then
-	 * use the deeper topology that is aware of this sharing.
-	 */
-	if (shared_caches) {
-		pr_info("Using shared cache scheduler topology\n");
-		set_sched_topology(power9_topology);
-	} else {
-		pr_info("Using standard scheduler topology\n");
-		set_sched_topology(powerpc_topology);
-	}
+	set_sched_topology(powerpc_topology);
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
-- 
2.18.2