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 <lkp@xxxxxxxxx>
The whole patch is not reported by kernel test robot. I think we should
drop this.
Signed-off-by: Song Liu <songliubraving@xxxxxx>
---
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 */
[...]
