| Message ID | 20240415094821.3060892-1-dawei.li@shingroup.cn (mailing list archive) |
|---|---|
| State | In Next |
| Delegated to: | Rafael Wysocki |
| Headers | show |
| Series | powercap: Avoid explicit cpumask allocation on stack | expand |
On Mon, Apr 15, 2024 at 11:48 AM Dawei Li <dawei.li@shingroup.cn> 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_weight_and() to avoid the need for a temporary cpumask on > the stack. > > Signed-off-by: Dawei Li <dawei.li@shingroup.cn> > --- > drivers/powercap/dtpm_cpu.c | 8 ++------ > 1 file changed, 2 insertions(+), 6 deletions(-) > > diff --git a/drivers/powercap/dtpm_cpu.c b/drivers/powercap/dtpm_cpu.c > index bc90126f1b5f..6b6f51b21550 100644 > --- a/drivers/powercap/dtpm_cpu.c > +++ b/drivers/powercap/dtpm_cpu.c > @@ -43,13 +43,11 @@ static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit) > struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); > struct em_perf_domain *pd = em_cpu_get(dtpm_cpu->cpu); > struct em_perf_state *table; > - struct cpumask cpus; > unsigned long freq; > u64 power; > int i, nr_cpus; > > - cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus)); > - nr_cpus = cpumask_weight(&cpus); > + nr_cpus = cpumask_weight_and(cpu_online_mask, to_cpumask(pd->cpus)); > > rcu_read_lock(); > table = em_perf_state_from_pd(pd); > @@ -123,11 +121,9 @@ static int update_pd_power_uw(struct dtpm *dtpm) > struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); > struct em_perf_domain *em = em_cpu_get(dtpm_cpu->cpu); > struct em_perf_state *table; > - struct cpumask cpus; > int nr_cpus; > > - cpumask_and(&cpus, cpu_online_mask, to_cpumask(em->cpus)); > - nr_cpus = cpumask_weight(&cpus); > + nr_cpus = cpumask_weight_and(cpu_online_mask, to_cpumask(em->cpus)); > > rcu_read_lock(); > table = em_perf_state_from_pd(em); > -- Applied as 6.10 material, thanks!
diff --git a/drivers/powercap/dtpm_cpu.c b/drivers/powercap/dtpm_cpu.c index bc90126f1b5f..6b6f51b21550 100644 --- a/drivers/powercap/dtpm_cpu.c +++ b/drivers/powercap/dtpm_cpu.c @@ -43,13 +43,11 @@ static u64 set_pd_power_limit(struct dtpm *dtpm, u64 power_limit) struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); struct em_perf_domain *pd = em_cpu_get(dtpm_cpu->cpu); struct em_perf_state *table; - struct cpumask cpus; unsigned long freq; u64 power; int i, nr_cpus; - cpumask_and(&cpus, cpu_online_mask, to_cpumask(pd->cpus)); - nr_cpus = cpumask_weight(&cpus); + nr_cpus = cpumask_weight_and(cpu_online_mask, to_cpumask(pd->cpus)); rcu_read_lock(); table = em_perf_state_from_pd(pd); @@ -123,11 +121,9 @@ static int update_pd_power_uw(struct dtpm *dtpm) struct dtpm_cpu *dtpm_cpu = to_dtpm_cpu(dtpm); struct em_perf_domain *em = em_cpu_get(dtpm_cpu->cpu); struct em_perf_state *table; - struct cpumask cpus; int nr_cpus; - cpumask_and(&cpus, cpu_online_mask, to_cpumask(em->cpus)); - nr_cpus = cpumask_weight(&cpus); + nr_cpus = cpumask_weight_and(cpu_online_mask, to_cpumask(em->cpus)); rcu_read_lock(); table = em_perf_state_from_pd(em);
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_weight_and() to avoid the need for a temporary cpumask on the stack. Signed-off-by: Dawei Li <dawei.li@shingroup.cn> --- drivers/powercap/dtpm_cpu.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-)