On Wed, Jan 3, 2024 at 6:13 AM Andrii Nakryiko
<andrii.nakryiko@xxxxxxxxx> wrote:
>
> On Fri, Dec 22, 2023 at 3:31 AM Yafang Shao <laoar.shao@xxxxxxxxx> wrote:
> >
> > Add three new kfuncs for bpf_iter_cpumask.
> > - bpf_iter_cpumask_new
> > - bpf_iter_cpumask_next
> > - bpf_iter_cpumask_destroy
> >
> > These new kfuncs facilitate the iteration of percpu data, such as
> > runqueues, psi_cgroup_cpu, and more.
> >
> > Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
> > ---
> > kernel/bpf/cpumask.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 48 insertions(+)
> >
> > diff --git a/kernel/bpf/cpumask.c b/kernel/bpf/cpumask.c
> > index 2e73533..4ae07a4 100644
> > --- a/kernel/bpf/cpumask.c
> > +++ b/kernel/bpf/cpumask.c
> > @@ -422,6 +422,51 @@ __bpf_kfunc u32 bpf_cpumask_weight(const struct cpumask *cpumask)
> > return cpumask_weight(cpumask);
> > }
> >
> > +struct bpf_iter_cpumask {
> > + __u64 __opaque[2];
> > +} __aligned(8);
> > +
> > +struct bpf_iter_cpumask_kern {
> > + struct cpumask *mask;
> > + int *cpu;
> > +} __aligned(8);
> > +
> > +__bpf_kfunc u32 bpf_iter_cpumask_new(struct bpf_iter_cpumask *it, struct cpumask *mask)
> > +{
> > + struct bpf_iter_cpumask_kern *kit = (void *)it;
> > +
> > + kit->cpu = bpf_mem_alloc(&bpf_global_ma, sizeof(*kit->cpu));
>
> why dynamic memory allocation of 4 bytes?... just have `int cpu;`
> field in bpf_iter_cpumask_kern?
Will do it. Thanks for your suggestion.
--
Regards
Yafang
