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From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Nicholas Piggin <npiggin@gmail.com>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
	Anton Vorontsov <anton.vorontsov@linaro.org>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] kernel/cpu: add arch override for clear_tasks_mm_cpumask() mm handling
Date: Fri, 20 Nov 2020 12:57:56 +1000	[thread overview]
Message-ID: <20201120025757.325930-2-npiggin@gmail.com> (raw)
In-Reply-To: <20201120025757.325930-1-npiggin@gmail.com>

powerpc keeps a counter in the mm which counts bits set in mm_cpumask as
well as other things. This means it can't use generic code to clear bits
out of the mask and doesn't adjust the arch specific counter.

Add an arch override allowing powerpc to use clear_tasks_mm_cpumask().

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 kernel/cpu.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 6ff2578ecf17..2b8d7a5db383 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -815,6 +815,10 @@ void __init cpuhp_threads_init(void)
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
+#ifndef arch_clear_mm_cpumask_cpu
+#define arch_clear_mm_cpumask_cpu(cpu, mm) cpumask_clear_cpu(cpu, mm_cpumask(mm))
+#endif
+
 /**
  * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU
  * @cpu: a CPU id
@@ -850,7 +854,7 @@ void clear_tasks_mm_cpumask(int cpu)
 		t = find_lock_task_mm(p);
 		if (!t)
 			continue;
-		cpumask_clear_cpu(cpu, mm_cpumask(t->mm));
+		arch_clear_mm_cpumask_cpu(cpu, t->mm);
 		task_unlock(t);
 	}
 	rcu_read_unlock();
-- 
2.23.0


WARNING: multiple messages have this Message-ID (diff)
From: Nicholas Piggin <npiggin@gmail.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>,
	"Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>,
	linux-kernel@vger.kernel.org, Nicholas Piggin <npiggin@gmail.com>,
	Anton Vorontsov <anton.vorontsov@linaro.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: [PATCH 1/2] kernel/cpu: add arch override for clear_tasks_mm_cpumask() mm handling
Date: Fri, 20 Nov 2020 12:57:56 +1000	[thread overview]
Message-ID: <20201120025757.325930-2-npiggin@gmail.com> (raw)
In-Reply-To: <20201120025757.325930-1-npiggin@gmail.com>

powerpc keeps a counter in the mm which counts bits set in mm_cpumask as
well as other things. This means it can't use generic code to clear bits
out of the mask and doesn't adjust the arch specific counter.

Add an arch override allowing powerpc to use clear_tasks_mm_cpumask().

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 kernel/cpu.c | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 6ff2578ecf17..2b8d7a5db383 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -815,6 +815,10 @@ void __init cpuhp_threads_init(void)
 }
 
 #ifdef CONFIG_HOTPLUG_CPU
+#ifndef arch_clear_mm_cpumask_cpu
+#define arch_clear_mm_cpumask_cpu(cpu, mm) cpumask_clear_cpu(cpu, mm_cpumask(mm))
+#endif
+
 /**
  * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU
  * @cpu: a CPU id
@@ -850,7 +854,7 @@ void clear_tasks_mm_cpumask(int cpu)
 		t = find_lock_task_mm(p);
 		if (!t)
 			continue;
-		cpumask_clear_cpu(cpu, mm_cpumask(t->mm));
+		arch_clear_mm_cpumask_cpu(cpu, t->mm);
 		task_unlock(t);
 	}
 	rcu_read_unlock();
-- 
2.23.0


  reply	other threads:[~2020-11-20  2:58 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-20  2:57 [PATCH 0/2] powerpc/64s: fix for CPU hotplug vs mm_cpumask bug Nicholas Piggin
2020-11-20  2:57 ` Nicholas Piggin
2020-11-20  2:57 ` Nicholas Piggin [this message]
2020-11-20  2:57   ` [PATCH 1/2] kernel/cpu: add arch override for clear_tasks_mm_cpumask() mm handling Nicholas Piggin
2020-11-20 10:06   ` Peter Zijlstra
2020-11-20 10:06     ` Peter Zijlstra
2020-11-20  2:57 ` [PATCH 2/2] powerpc/64s: Trim offlined CPUs from mm_cpumasks Nicholas Piggin
2020-11-20  2:57   ` Nicholas Piggin
2020-12-10  9:06   ` Geert Uytterhoeven
2020-12-10  9:06     ` Geert Uytterhoeven
2020-12-14  4:15     ` Nicholas Piggin
2020-12-14  4:15       ` Nicholas Piggin
2020-12-14 10:43       ` Michael Ellerman
2020-12-14 10:43         ` Michael Ellerman
2020-12-14 11:04         ` Nicholas Piggin
2020-12-14 11:04           ` Nicholas Piggin
2020-12-15 10:33           ` Michael Ellerman
2020-12-15 10:33             ` Michael Ellerman

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