Commit 8ff00399 authored Nov 26, 2020 by Nicholas Piggin Committed by Michael Ellerman Nov 27, 2020

kernel/cpu: add arch override for clear_tasks_mm_cpumask() mm handling



powerpc/64s 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 that allows powerpc/64s to use
clear_tasks_mm_cpumask().

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201126102530.691335-4-npiggin@gmail.com

parent c0b27c51

kernel/cpu.c

+5 −1

Original line number	Diff line number	Diff line
		@@ -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();

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