smp, cpumask: Use non-atomic cpumask_{set,clear}_cpu()

The cpumasks in smp_call_function_many() are private and not subject
to concurrency, atomic bitops are pointless and expensive.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index a21b1fb9a9689fdf1bf8157c8b5457bd053784e2..4bf4479a3a800c435ccec039f7e5da4089910f87 100644 (file)
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -293,6 +293,12 @@ static inline void cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp)
        set_bit(cpumask_check(cpu), cpumask_bits(dstp));
 }
 
+static inline void __cpumask_set_cpu(unsigned int cpu, struct cpumask *dstp)
+{
+       __set_bit(cpumask_check(cpu), cpumask_bits(dstp));
+}
+
+
 /**
  * cpumask_clear_cpu - clear a cpu in a cpumask
  * @cpu: cpu number (< nr_cpu_ids)
@@ -303,6 +309,11 @@ static inline void cpumask_clear_cpu(int cpu, struct cpumask *dstp)
        clear_bit(cpumask_check(cpu), cpumask_bits(dstp));
 }
 
+static inline void __cpumask_clear_cpu(int cpu, struct cpumask *dstp)
+{
+       __clear_bit(cpumask_check(cpu), cpumask_bits(dstp));
+}
+
 /**
  * cpumask_test_cpu - test for a cpu in a cpumask
  * @cpu: cpu number (< nr_cpu_ids)

diff --git a/kernel/smp.c b/kernel/smp.c
index 76d16fe3c427d19c2ec534e887894ba38692bdfa..3061483cb3ad3eac437046eda0634f8a152e07f2 100644 (file)
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -436,7 +436,7 @@ void smp_call_function_many(const struct cpumask *mask,
        cfd = this_cpu_ptr(&cfd_data);
 
        cpumask_and(cfd->cpumask, mask, cpu_online_mask);
-       cpumask_clear_cpu(this_cpu, cfd->cpumask);
+       __cpumask_clear_cpu(this_cpu, cfd->cpumask);
 
        /* Some callers race with other cpus changing the passed mask */
        if (unlikely(!cpumask_weight(cfd->cpumask)))
@@ -452,7 +452,7 @@ void smp_call_function_many(const struct cpumask *mask,
                csd->func = func;
                csd->info = info;
                if (llist_add(&csd->llist, &per_cpu(call_single_queue, cpu)))
-                       cpumask_set_cpu(cpu, cfd->cpumask_ipi);
+                       __cpumask_set_cpu(cpu, cfd->cpumask_ipi);
        }
 
        /* Send a message to all CPUs in the map */