Re: [PATCH bpf-next 1/4] bpf: enable task local storage for tracing programs
From: Yonghong Song <hidden>
Date: 2021-01-11 17:18:08
Also in:
bpf, lkml
On 1/8/21 3:19 PM, Song Liu wrote:
To access per-task data, BPF program typically creates a hash table with
pid as the key. This is not ideal because:
1. The use need to estimate requires size of the hash table, with may be
inaccurate;
2. Big hash tables are slow;
3. To clean up the data properly during task terminations, the user need
to write code.
Task local storage overcomes these issues and becomes a better option for
these per-task data. Task local storage is only available to BPF_LSM. Now
enable it for tracing programs.
Reported-by: kernel test robot <redacted>The whole patch is not reported by kernel test robot. I think we should drop this.
quoted hunk
Signed-off-by: Song Liu <redacted> --- include/linux/bpf.h | 7 +++++++ include/linux/bpf_lsm.h | 22 ---------------------- include/linux/bpf_types.h | 2 +- include/linux/sched.h | 5 +++++ kernel/bpf/Makefile | 3 +-- kernel/bpf/bpf_local_storage.c | 28 +++++++++++++++++----------- kernel/bpf/bpf_lsm.c | 4 ---- kernel/bpf/bpf_task_storage.c | 26 ++++++-------------------- kernel/fork.c | 5 +++++ kernel/trace/bpf_trace.c | 4 ++++ 10 files changed, 46 insertions(+), 60 deletions(-)diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 07cb5d15e7439..cf16548f28f7b 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h@@ -1480,6 +1480,7 @@ struct bpf_prog *bpf_prog_by_id(u32 id); struct bpf_link *bpf_link_by_id(u32 id); const struct bpf_func_proto *bpf_base_func_proto(enum bpf_func_id func_id); +void bpf_task_storage_free(struct task_struct *task); #else /* !CONFIG_BPF_SYSCALL */ static inline struct bpf_prog *bpf_prog_get(u32 ufd) {@@ -1665,6 +1666,10 @@ bpf_base_func_proto(enum bpf_func_id func_id) { return NULL; } + +static inline void bpf_task_storage_free(struct task_struct *task) +{ +} #endif /* CONFIG_BPF_SYSCALL */
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