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Subject[PATCH v3 02/10] perf/alibaba_uncore_drw: Avoid placing cpumask on the stack
Date
In general it's preferable to avoid placing cpumasks on the stack, as
for large values of NR_CPUS these can consume significant amounts of
stack space and make stack overflows more likely.

Use cpumask_any_and_but() to avoid the need for a temporary cpumask on
the stack.

Suggested-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Dawei Li <dawei.li@shingroup.cn>
---
drivers/perf/alibaba_uncore_drw_pmu.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/perf/alibaba_uncore_drw_pmu.c b/drivers/perf/alibaba_uncore_drw_pmu.c
index a9277dcf90ce..d4d14b65c4a5 100644
--- a/drivers/perf/alibaba_uncore_drw_pmu.c
+++ b/drivers/perf/alibaba_uncore_drw_pmu.c
@@ -746,18 +746,14 @@ static int ali_drw_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node)
struct ali_drw_pmu_irq *irq;
struct ali_drw_pmu *drw_pmu;
unsigned int target;
- int ret;
- cpumask_t node_online_cpus;

irq = hlist_entry_safe(node, struct ali_drw_pmu_irq, node);
if (cpu != irq->cpu)
return 0;

- ret = cpumask_and(&node_online_cpus,
- cpumask_of_node(cpu_to_node(cpu)), cpu_online_mask);
- if (ret)
- target = cpumask_any_but(&node_online_cpus, cpu);
- else
+ target = cpumask_any_and_but(cpumask_of_node(cpu_to_node(cpu)),
+ cpu_online_mask, cpu);
+ if (target >= nr_cpu_ids)
target = cpumask_any_but(cpu_online_mask, cpu);

if (target >= nr_cpu_ids)
--
2.27.0

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