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From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nathan Lynch <nathanl@linux.ibm.com>,
	Gautham R Shenoy <ego@linux.vnet.ibm.com>,
	Michael Neuling <mikey@neuling.org>,
	Srikar Dronamraju <srikar@linux.vnet.ibm.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Jordan Niethe <jniethe5@gmail.com>,
	LKML <linux-kernel@vger.kernel.org>,
	Nicholas Piggin <npiggin@gmail.com>,
	Valentin Schneider <valentin.schneider@arm.com>,
	Oliver O'Halloran <oohall@gmail.com>,
	linuxppc-dev <linuxppc-dev@lists.ozlabs.org>,
	Ingo Molnar <mingo@kernel.org>
Subject: [PATCH v4 05/10] powerpc/smp: Dont assume l2-cache to be superset of sibling
Date: Mon, 27 Jul 2020 11:02:25 +0530	[thread overview]
Message-ID: <20200727053230.19753-6-srikar@linux.vnet.ibm.com> (raw)
In-Reply-To: <20200727053230.19753-1-srikar@linux.vnet.ibm.com>

Current code assumes that cpumask of cpus sharing a l2-cache mask will
always be a superset of cpu_sibling_mask.

Lets stop that assumption. cpu_l2_cache_mask is a superset of
cpu_sibling_mask if and only if shared_caches is set.

Cc: linuxppc-dev <linuxppc-dev@lists.ozlabs.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Anton Blanchard <anton@ozlabs.org>
Cc: Oliver O'Halloran <oohall@gmail.com>
Cc: Nathan Lynch <nathanl@linux.ibm.com>
Cc: Michael Neuling <mikey@neuling.org>
Cc: Gautham R Shenoy <ego@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Valentin Schneider <valentin.schneider@arm.com>
Cc: Jordan Niethe <jniethe5@gmail.com>
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---
Changelog v1 -> v2:
	Set cpumask after verifying l2-cache. (Gautham)

 arch/powerpc/kernel/smp.c | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index da27f6909be1..d997c7411664 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -1194,6 +1194,7 @@ static bool update_mask_by_l2(int cpu, struct cpumask *(*mask_fn)(int))
 	if (!l2_cache)
 		return false;
 
+	cpumask_set_cpu(cpu, mask_fn(cpu));
 	for_each_cpu(i, cpu_online_mask) {
 		/*
 		 * when updating the marks the current CPU has not been marked
@@ -1276,29 +1277,30 @@ static void add_cpu_to_masks(int cpu)
 	 * add it to it's own thread sibling mask.
 	 */
 	cpumask_set_cpu(cpu, cpu_sibling_mask(cpu));
+	cpumask_set_cpu(cpu, cpu_core_mask(cpu));
 
 	for (i = first_thread; i < first_thread + threads_per_core; i++)
 		if (cpu_online(i))
 			set_cpus_related(i, cpu, cpu_sibling_mask);
 
 	add_cpu_to_smallcore_masks(cpu);
-	/*
-	 * Copy the thread sibling mask into the cache sibling mask
-	 * and mark any CPUs that share an L2 with this CPU.
-	 */
-	for_each_cpu(i, cpu_sibling_mask(cpu))
-		set_cpus_related(cpu, i, cpu_l2_cache_mask);
 	update_mask_by_l2(cpu, cpu_l2_cache_mask);
 
-	/*
-	 * Copy the cache sibling mask into core sibling mask and mark
-	 * any CPUs on the same chip as this CPU.
-	 */
-	for_each_cpu(i, cpu_l2_cache_mask(cpu))
-		set_cpus_related(cpu, i, cpu_core_mask);
+	if (pkg_id == -1) {
+		struct cpumask *(*mask)(int) = cpu_sibling_mask;
+
+		/*
+		 * Copy the sibling mask into core sibling mask and
+		 * mark any CPUs on the same chip as this CPU.
+		 */
+		if (shared_caches)
+			mask = cpu_l2_cache_mask;
+
+		for_each_cpu(i, mask(cpu))
+			set_cpus_related(cpu, i, cpu_core_mask);
 
-	if (pkg_id == -1)
 		return;
+	}
 
 	for_each_cpu(i, cpu_online_mask)
 		if (get_physical_package_id(i) == pkg_id)
-- 
2.17.1


  parent reply	other threads:[~2020-07-27  5:52 UTC|newest]

Thread overview: 32+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-27  5:32 [PATCH v4 00/10] Coregroup support on Powerpc Srikar Dronamraju
2020-07-27  5:32 ` [PATCH v4 01/10] powerpc/smp: Fix a warning under !NEED_MULTIPLE_NODES Srikar Dronamraju
2020-07-27  5:32 ` [PATCH v4 02/10] powerpc/smp: Merge Power9 topology with Power topology Srikar Dronamraju
2020-07-27  5:32 ` [PATCH v4 03/10] powerpc/smp: Move powerpc_topology above Srikar Dronamraju
2020-07-27  5:32 ` [PATCH v4 04/10] powerpc/smp: Move topology fixups into a new function Srikar Dronamraju
2020-07-27  5:32 ` Srikar Dronamraju [this message]
2020-07-27  5:32 ` [PATCH v4 06/10] powerpc/smp: Generalize 2nd sched domain Srikar Dronamraju
2020-07-30  5:55   ` Gautham R Shenoy
2020-07-31  7:45   ` Michael Ellerman
2020-07-31  9:29     ` Srikar Dronamraju
2020-07-31 12:22       ` Michael Ellerman
2020-07-27  5:32 ` [PATCH v4 07/10] Powerpc/numa: Detect support for coregroup Srikar Dronamraju
2020-07-31  7:49   ` Michael Ellerman
2020-07-31  9:18     ` Srikar Dronamraju
2020-07-31 11:31       ` Michael Ellerman
2020-07-27  5:32 ` [PATCH v4 08/10] powerpc/smp: Allocate cpumask only after searching thread group Srikar Dronamraju
2020-07-31  7:52   ` Michael Ellerman
2020-07-31  9:49     ` Srikar Dronamraju
2020-07-31 12:14       ` Michael Ellerman
2020-07-27  5:32 ` [PATCH v4 09/10] Powerpc/smp: Create coregroup domain Srikar Dronamraju
2020-07-27 18:52   ` Gautham R Shenoy
2020-07-28 15:03   ` Valentin Schneider
2020-07-29  6:13     ` Srikar Dronamraju
2020-07-31  1:05       ` Valentin Schneider
2020-08-03  6:01         ` Srikar Dronamraju
2020-07-31  7:36       ` Gautham R Shenoy
2020-07-27  5:32 ` [PATCH v4 10/10] powerpc/smp: Implement cpu_to_coregroup_id Srikar Dronamraju
2020-07-31  8:02   ` Michael Ellerman
2020-07-31  9:58     ` Srikar Dronamraju
2020-07-31 11:29       ` Michael Ellerman
2020-07-30 17:22 ` [PATCH v4 00/10] Coregroup support on Powerpc Srikar Dronamraju
  -- strict thread matches above, loose matches on Subject: below --
2020-07-27  5:17 Srikar Dronamraju
2020-07-27  5:18 ` [PATCH v4 05/10] powerpc/smp: Dont assume l2-cache to be superset of sibling Srikar Dronamraju

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