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 <[email protected]>
The whole patch is not reported by kernel test robot. I think we should
drop this.
> Signed-off-by: Song Liu <[email protected]>
> ---
> 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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