diff options
| author | Song Liu <songliubraving@fb.com> | 2021-02-25 15:43:14 -0800 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2021-02-26 11:51:47 -0800 |
| commit | a10787e6d58c24b51e91c19c6d16c5da89fcaa4b (patch) | |
| tree | 115e4d7d43d1353084fc3b9e54935aad16c6f821 /include/linux/bpf_types.h | |
| parent | 9c8f21e6f8856a96634e542a58ef3abf27486801 (diff) | |
bpf: Enable task local storage for tracing programs
To access per-task data, BPF programs usually creates a hash table with
pid as the key. This is not ideal because:
1. The user need to estimate the proper size of the hash table, which may
be inaccurate;
2. Big hash tables are slow;
3. To clean up the data properly during task terminations, the user need
to write extra logic.
Task local storage overcomes these issues and offers a better option for
these per-task data. Task local storage is only available to BPF_LSM. Now
enable it for tracing programs.
Unlike LSM programs, tracing programs can be called in IRQ contexts.
Helpers that access task local storage are updated to use
raw_spin_lock_irqsave() instead of raw_spin_lock_bh().
Tracing programs can attach to functions on the task free path, e.g.
exit_creds(). To avoid allocating task local storage after
bpf_task_storage_free(). bpf_task_storage_get() is updated to not allocate
new storage when the task is not refcounted (task->usage == 0).
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: KP Singh <kpsingh@kernel.org>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20210225234319.336131-2-songliubraving@fb.com
Diffstat (limited to 'include/linux/bpf_types.h')
| -rw-r--r-- | include/linux/bpf_types.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/bpf_types.h b/include/linux/bpf_types.h index 99f7fd657d87..b9edee336d80 100644 --- a/include/linux/bpf_types.h +++ b/include/linux/bpf_types.h @@ -109,8 +109,8 @@ BPF_MAP_TYPE(BPF_MAP_TYPE_SOCKHASH, sock_hash_ops) #endif #ifdef CONFIG_BPF_LSM BPF_MAP_TYPE(BPF_MAP_TYPE_INODE_STORAGE, inode_storage_map_ops) -BPF_MAP_TYPE(BPF_MAP_TYPE_TASK_STORAGE, task_storage_map_ops) #endif +BPF_MAP_TYPE(BPF_MAP_TYPE_TASK_STORAGE, task_storage_map_ops) BPF_MAP_TYPE(BPF_MAP_TYPE_CPUMAP, cpu_map_ops) #if defined(CONFIG_XDP_SOCKETS) BPF_MAP_TYPE(BPF_MAP_TYPE_XSKMAP, xsk_map_ops) |