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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 <namit@vmware.com>
Signed-off-by: Thomas 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
This commit is contained in:
Nadav Amit 2019-06-12 23:48:13 -07:00 committed by Thomas Gleixner
parent 748b170ca1
commit dde3626f81
3 changed files with 4 additions and 4 deletions
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4
arch/x86/kernel/apic/apic_flat_64.c
View File

@ -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);
}

2
arch/x86/kernel/apic/x2apic_cluster.c
View File

@ -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) {

2
arch/x86/kernel/smp.c
View File

@ -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))