Re: [RFC PATCH bpf-next v2 2/3] bpf, libbpf: Support BPF_F_CPU for percpu_array map

[Leon Hwang <leon.hwang@linux.dev>]

On 2025/7/12 02:10, Andrii Nakryiko wrote:
> On Mon, Jul 7, 2025 at 9:04 AM Leon Hwang <leon.hwang@linux.dev> wrote:
>>
>> This patch adds libbpf support for the BPF_F_CPU flag in percpu_array maps,
>> introducing the following APIs:
>>
>> 1. bpf_map_update_elem_opts(): update with struct bpf_map_update_elem_opts
>> 2. bpf_map_lookup_elem_opts(): lookup with struct bpf_map_lookup_elem_opts
>> 3. bpf_map__update_elem_opts(): high-level wrapper with input validation
>> 4. bpf_map__lookup_elem_opts(): high-level wrapper with input validation
>>
>> Behavior:
>>
>> * If opts->cpu == (u32)~0, the update is applied to all CPUs.
>> * Otherwise, it applies only to the specified CPU.
>> * Lookup APIs retrieve values from the target CPU when BPF_F_CPU is used.
>>
>> Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
>> ---
>>  tools/lib/bpf/bpf.c           | 23 ++++++++++++++
>>  tools/lib/bpf/bpf.h           | 36 +++++++++++++++++++++-
>>  tools/lib/bpf/libbpf.c        | 56 +++++++++++++++++++++++++++++++----
>>  tools/lib/bpf/libbpf.h        | 53 ++++++++++++++++++++++++++++-----
>>  tools/lib/bpf/libbpf.map      |  4 +++
>>  tools/lib/bpf/libbpf_common.h | 14 +++++++++
>>  6 files changed, 172 insertions(+), 14 deletions(-)
>>
> 
> LGTM, just see the note about libpbf.map file, thanks.
> 
>> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
>> index 1bbf77326420..d21288991d1c 100644
>> --- a/tools/lib/bpf/libbpf.map
>> +++ b/tools/lib/bpf/libbpf.map
>> @@ -436,6 +436,10 @@ LIBBPF_1.6.0 {
>>                 bpf_linker__add_buf;
>>                 bpf_linker__add_fd;
>>                 bpf_linker__new_fd;
>> +               bpf_map__lookup_elem_opts;
>> +               bpf_map__update_elem_opts;
>> +               bpf_map_lookup_elem_opts;
>> +               bpf_map_update_elem_opts;
> 
> I'm planning to cut libbpf 1.6 release early next week, so for the
> next revision please add it into 1.7 section
> 

No problem.

Thanks,
Leon

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