Commit-ID: 6c8557bdb28df3ae97476c5e2aed6373cd235aab
Gitweb: http://git.kernel.org/tip/6c8557bdb28df3ae97476c5e2aed6373cd235aab
Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate: Fri, 19 May 2017 12:58:25 +0200
Committer: Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 23 May 2017 10:01:32 +0200
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@xxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
include/linux/cpumask.h | 11 +++++++++++
kernel/smp.c | 4 ++--
2 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index a21b1fb..4bf4479 100644
--- 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 76d16fe..3061483 100644
--- 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 */
--
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