diff mbox series

[v3,02/10] perf/alibaba_uncore_drw: Avoid placing cpumask on the stack

Message ID 20240403155950.2068109-3-dawei.li@shingroup.cn
State New
Headers show
Series perf: Avoid placing cpumask on the stack | expand

Commit Message

Dawei Li April 3, 2024, 3:59 p.m. UTC 
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(-)

Comments

Shuai Xue April 8, 2024, 12:28 a.m. UTC | #1 
On 2024/4/3 23:59, Dawei Li wrote:
> 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>
> ---

Reviewed-by: Shuai Xue <xueshuai@linux.alibaba.com>
diff mbox series

Patch

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)