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From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: Mark Rutland <mark.rutland@arm.com>,
	Valentin Schneider <vschneid@redhat.com>,
	Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	linux-kernel@vger.kernel.org,
	Rohan McLure <rmclure@linux.ibm.com>,
	Nicholas Piggin <npiggin@gmail.com>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
	Josh Poimboeuf <jpoimboe@kernel.org>
Subject: [PATCH v2 4/6] powerpc/smp: Disable MC domain for shared processor
Date: Wed, 18 Oct 2023 22:07:44 +0530	[thread overview]
Message-ID: <20231018163751.2423181-5-srikar@linux.vnet.ibm.com> (raw)
In-Reply-To: <20231018163751.2423181-1-srikar@linux.vnet.ibm.com>

Like L2-cache info, coregroup information which is used to determine MC
sched domains is only present on dedicated LPARs. i.e PowerVM doesn't
export coregroup information for shared processor LPARs. Hence disable
creating MC domains on shared LPAR Systems.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/smp.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 498c2d51fc20..29da9262cb17 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1046,6 +1046,10 @@ static struct cpumask *cpu_coregroup_mask(int cpu)
 
 static bool has_coregroup_support(void)
 {
+	/* Coregroup identification not available on shared systems */
+	if (is_shared_processor())
+		return 0;
+
 	return coregroup_enabled;
 }
 
-- 
2.31.1


  parent reply	other threads:[~2023-10-18 16:43 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-18 16:37 [PATCH v2 0/6] powerpc/smp: Shared processor sched optimizations Srikar Dronamraju
2023-10-18 16:37 ` [PATCH v2 1/6] powerpc/smp: Cache CPU has Asymmetric SMP Srikar Dronamraju
2023-10-19  4:33   ` Michael Ellerman
2023-10-20  9:09     ` Srikar Dronamraju
2023-10-18 16:37 ` [PATCH v2 2/6] powerpc/smp: Enable Asym packing for cores on shared processor Srikar Dronamraju
2023-10-19  4:38   ` Michael Ellerman
2023-10-19  7:48     ` Peter Zijlstra
2023-10-19 11:50       ` Michael Ellerman
2023-10-19 12:54       ` Srikar Dronamraju
2023-10-19 15:56   ` Shrikanth Hegde
2023-10-20  5:44     ` Srikar Dronamraju
2023-10-18 16:37 ` [PATCH v2 3/6] powerpc/smp: Move shared_processor static key to smp.h Srikar Dronamraju
2023-10-19  4:41   ` Michael Ellerman
2023-10-19 13:08     ` Srikar Dronamraju
2023-10-20 10:44       ` Michael Ellerman
2023-10-19 10:30   ` Shrikanth Hegde
2023-10-18 16:37 ` Srikar Dronamraju [this message]
2023-10-19  4:48   ` [PATCH v2 4/6] powerpc/smp: Disable MC domain for shared processor Michael Ellerman
2023-10-19  7:50     ` Peter Zijlstra
2023-10-19 13:23       ` Srikar Dronamraju
2023-10-19 13:16     ` Srikar Dronamraju
2023-10-18 16:37 ` [PATCH v2 5/6] powerpc/smp: Add read_mostly attribute Srikar Dronamraju
2023-10-19  4:49   ` Michael Ellerman
2023-10-19  7:51   ` Peter Zijlstra
2023-10-19 12:56     ` Srikar Dronamraju
2023-10-18 16:37 ` [PATCH v2 6/6] powerpc/smp: Avoid asym packing within thread_group of a core Srikar Dronamraju

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