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: Nadav Amit <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Dave Hansen <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
kmaincent · Jun 23, 2019 · dde3626 · dde3626
1 parent 748b170
commit dde3626
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Showing 3 changed files with 4 additions and 4 deletions.
diff --git a/arch/x86/kernel/apic/apic_flat_64.c b/arch/x86/kernel/apic/apic_flat_64.c
@@ -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);
 		}

diff --git a/arch/x86/kernel/apic/x2apic_cluster.c b/arch/x86/kernel/apic/x2apic_cluster.c
@@ -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) {

diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
@@ -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))