From: Yafang Shao <laoar.shao@gmail.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: ast@kernel.org, daniel@iogearbox.net, john.fastabend@gmail.com,
andrii@kernel.org, martin.lau@linux.dev, song@kernel.org,
yonghong.song@linux.dev, kpsingh@kernel.org, sdf@google.com,
haoluo@google.com, jolsa@kernel.org, tj@kernel.org,
lizefan.x@bytedance.com, hannes@cmpxchg.org,
bpf@vger.kernel.org, cgroups@vger.kernel.org
Subject: Re: [PATCH bpf-next 2/4] bpf: Add bpf_iter_cpumask kfuncs
Date: Thu, 4 Jan 2024 10:30:21 +0800 [thread overview]
Message-ID: <CALOAHbCU57P54Ocx=PH-afu26K5pJK6cPvSyF9KStWcFe+Ov7Q@mail.gmail.com> (raw)
In-Reply-To: <CAEf4BzbvPFYx3JpUaKnpG=HaNheQkJbUfaTd=DW0GbYi4A-A7A@mail.gmail.com>
On Wed, Jan 3, 2024 at 6:13 AM Andrii Nakryiko
<andrii.nakryiko@gmail.com> wrote:
>
> On Fri, Dec 22, 2023 at 3:31 AM Yafang Shao <laoar.shao@gmail.com> 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@gmail.com>
> > ---
> > 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
next prev parent reply other threads:[~2024-01-04 2:30 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-22 11:30 [PATCH bpf-next 0/4] bpf: Add bpf_iter_cpumask Yafang Shao
2023-12-22 11:30 ` [PATCH bpf-next 1/4] cgroup, psi: Init PSI of root cgroup to psi_system Yafang Shao
2023-12-22 17:47 ` Tejun Heo
2023-12-24 3:14 ` Yafang Shao
2023-12-22 23:49 ` kernel test robot
2023-12-23 7:26 ` kernel test robot
2023-12-22 11:31 ` [PATCH bpf-next 2/4] bpf: Add bpf_iter_cpumask kfuncs Yafang Shao
2024-01-02 22:13 ` Andrii Nakryiko
2024-01-04 2:30 ` Yafang Shao [this message]
2023-12-22 11:31 ` [PATCH bpf-next 3/4] bpf: Add new kfunc bpf_cpumask_set_from_pid Yafang Shao
2023-12-22 17:51 ` Tejun Heo
2023-12-24 3:05 ` Yafang Shao
2023-12-22 11:31 ` [PATCH bpf-next 4/4] selftests/bpf: Add selftests for cpumask iter Yafang Shao
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