Commit dde3626f authored by Nadav Amit's avatar Nadav Amit Committed by Thomas Gleixner
Browse files

x86/apic: Use non-atomic operations when possible 



Using __clear_bit() and __cpumask_clear_cpu() is more efficient than using
their atomic counterparts.

Use them when atomicity is not needed, such as when manipulating bitmasks
that are on the stack.

Signed-off-by: default avatarNadav Amit <namit@vmware.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Link: https://lkml.kernel.org/r/20190613064813.8102-10-namit@vmware.com
parent 748b170c

arch/x86/kernel/apic/apic_flat_64.c

+2 −2
Original line number Diff line number Diff line
@@ -78,7 +78,7 @@ flat_send_IPI_mask_allbutself(const struct cpumask *cpumask, int vector) 
	int cpu = smp_processor_id();



	if (cpu < BITS_PER_LONG)

		clear_bit(cpu, &mask);

		__clear_bit(cpu, &mask);



	_flat_send_IPI_mask(mask, vector);

}
@@ -92,7 +92,7 @@ static void flat_send_IPI_allbutself(int vector) 
			unsigned long mask = cpumask_bits(cpu_online_mask)[0];



			if (cpu < BITS_PER_LONG)

				clear_bit(cpu, &mask);

				__clear_bit(cpu, &mask);



			_flat_send_IPI_mask(mask, vector);

		}

arch/x86/kernel/apic/x2apic_cluster.c

+1 −1
Original line number Diff line number Diff line
@@ -50,7 +50,7 @@ __x2apic_send_IPI_mask(const struct cpumask *mask, int vector, int apic_dest) 
	cpumask_copy(tmpmsk, mask);

	/* If IPI should not be sent to self, clear current CPU */

	if (apic_dest != APIC_DEST_ALLINC)

		cpumask_clear_cpu(smp_processor_id(), tmpmsk);

		__cpumask_clear_cpu(smp_processor_id(), tmpmsk);



	/* Collapse cpus in a cluster so a single IPI per cluster is sent */

	for_each_cpu(cpu, tmpmsk) {

arch/x86/kernel/smp.c

+1 −1
Original line number Diff line number Diff line
@@ -146,7 +146,7 @@ void native_send_call_func_ipi(const struct cpumask *mask) 
	}



	cpumask_copy(allbutself, cpu_online_mask);

	cpumask_clear_cpu(smp_processor_id(), allbutself);

	__cpumask_clear_cpu(smp_processor_id(), allbutself);



	if (cpumask_equal(mask, allbutself) &&

	    cpumask_equal(cpu_online_mask, cpu_callout_mask))

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