linux-kernel - [PATCH v2 04/10] powerpc/smp: Enable small core scheduling sooner

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Date:   Tue, 21 Jul 2020 17:08:08 +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 04/10] powerpc/smp: Enable small core scheduling sooner

Enable small core scheduling as soon as we detect that we are in a
system that supports thread group. Doing so would avoid a redundant
check.

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>
Signed-off-by: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
---
Changelog v1 -> v2:
powerpc/smp: Enable small core scheduling sooner
	Restored the previous info msg (Jordan)
	Moved big core topology fixup to fixup_topology (Gautham)

 arch/powerpc/kernel/smp.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 1ce95da00cb6..72f16dc0cb26 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1370,6 +1370,16 @@ int setup_profiling_timer(unsigned int multiplier)
 	return 0;
 }
 
+static void fixup_topology(void)
+{
+#ifdef CONFIG_SCHED_SMT
+	if (has_big_cores) {
+		pr_info("Big cores detected but using small core scheduling\n");
+		powerpc_topology[0].mask = smallcore_smt_mask;
+	}
+#endif
+}
+
 void __init smp_cpus_done(unsigned int max_cpus)
 {
 	/*
@@ -1383,12 +1393,7 @@ void __init smp_cpus_done(unsigned int max_cpus)
 
 	dump_numa_cpu_topology();
 
-#ifdef CONFIG_SCHED_SMT
-	if (has_big_cores) {
-		pr_info("Big cores detected but using small core scheduling\n");
-		powerpc_topology[0].mask = smallcore_smt_mask;
-	}
-#endif
+	fixup_topology();
 	set_sched_topology(powerpc_topology);
 }
 
-- 
2.17.1