mbox series

[bpf-next,v3,0/2] Introduce access remote cpu elem support in BPF percpu map

Message ID 20220513063952.41794-1-zhoufeng.zf@bytedance.com (mailing list archive)
Headers show
Series Introduce access remote cpu elem support in BPF percpu map | expand

Message

Feng Zhou May 13, 2022, 6:39 a.m. UTC
From: Feng Zhou <zhoufeng.zf@bytedance.com>

Trace some functions, such as enqueue_task_fair, need to access the
corresponding cpu, not the current cpu, and bpf_map_lookup_elem percpu map
cannot do it. So add bpf_map_lookup_percpu_elem to accomplish it for
percpu_array_map, percpu_hash_map, lru_percpu_hash_map.

Changelog:
----------
v2->v3: Addressed comments from Andrii Nakryiko.
- use /* */ instead of //
- use libbpf_num_possible_cpus() instead of sysconf(_SC_NPROCESSORS_ONLN)
- use 8 bytes for value size
- fix memory leak
- use ASSERT_EQ instead of ASSERT_OK
- add bpf_loop to fetch values on each possible CPU
some details in here:
https://lore.kernel.org/lkml/20220511093854.411-1-zhoufeng.zf@bytedance.com/T/

v1->v2: Addressed comments from Alexei Starovoitov.
- add a selftest for bpf_map_lookup_percpu_elem.

Feng Zhou (2):
  bpf: add bpf_map_lookup_percpu_elem for percpu map
  selftests/bpf: add test case for bpf_map_lookup_percpu_elem

 include/linux/bpf.h                           |  2 +
 include/uapi/linux/bpf.h                      |  9 +++
 kernel/bpf/arraymap.c                         | 15 ++++
 kernel/bpf/core.c                             |  1 +
 kernel/bpf/hashtab.c                          | 32 +++++++++
 kernel/bpf/helpers.c                          | 18 +++++
 kernel/bpf/verifier.c                         | 17 ++++-
 kernel/trace/bpf_trace.c                      |  2 +
 tools/include/uapi/linux/bpf.h                |  9 +++
 .../bpf/prog_tests/map_lookup_percpu_elem.c   | 59 +++++++++++++++
 .../bpf/progs/test_map_lookup_percpu_elem.c   | 71 +++++++++++++++++++
 11 files changed, 233 insertions(+), 2 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/map_lookup_percpu_elem.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_map_lookup_percpu_elem.c

Comments

Daniel Borkmann May 13, 2022, 3:01 p.m. UTC | #1
On 5/13/22 8:39 AM, Feng zhou wrote:
[...]
> Changelog:
> ----------
> v2->v3: Addressed comments from Andrii Nakryiko.
> - use /* */ instead of //
> - use libbpf_num_possible_cpus() instead of sysconf(_SC_NPROCESSORS_ONLN)
> - use 8 bytes for value size
> - fix memory leak
> - use ASSERT_EQ instead of ASSERT_OK
> - add bpf_loop to fetch values on each possible CPU
> some details in here:
> https://lore.kernel.org/lkml/20220511093854.411-1-zhoufeng.zf@bytedance.com/T/

The v2 of your series is already in bpf-next tree, please just send a relative diff for
the selftest patch.

https://lore.kernel.org/lkml/165231901346.29050.11394051230756915389.git-patchwork-notify@kernel.org/

Thanks,
Daniel
Feng Zhou May 16, 2022, 1:55 a.m. UTC | #2
在 2022/5/13 下午11:01, Daniel Borkmann 写道:
> On 5/13/22 8:39 AM, Feng zhou wrote:
> [...]
>> Changelog:
>> ----------
>> v2->v3: Addressed comments from Andrii Nakryiko.
>> - use /* */ instead of //
>> - use libbpf_num_possible_cpus() instead of 
>> sysconf(_SC_NPROCESSORS_ONLN)
>> - use 8 bytes for value size
>> - fix memory leak
>> - use ASSERT_EQ instead of ASSERT_OK
>> - add bpf_loop to fetch values on each possible CPU
>> some details in here:
>> https://lore.kernel.org/lkml/20220511093854.411-1-zhoufeng.zf@bytedance.com/T/ 
>>
>
> The v2 of your series is already in bpf-next tree, please just send a 
> relative diff for
> the selftest patch.
>
> https://lore.kernel.org/lkml/165231901346.29050.11394051230756915389.git-patchwork-notify@kernel.org/ 
>
>
> Thanks,
> Daniel

Ok, will do. Thanks.