Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: [PATCH v5 bpf-next 1/6] bpf: enable task local storage for tracing programs | From | Yonghong Song <> | Date | Tue, 23 Feb 2021 17:00:36 -0800 |
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On 2/23/21 2:28 PM, Song Liu wrote: > 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). > > Reported-by: kernel test robot <lkp@intel.com>
For a patch like this, typically we do not put the above Reported-by here as it is not really reported by the kernel test robot. If no revision is required, maybe maintainer can remove it before applying.
> Acked-by: KP Singh <kpsingh@kernel.org> > Signed-off-by: Song Liu <songliubraving@fb.com> > --- > 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 | 43 +++++++++------------------------- > kernel/fork.c | 5 ++++ > kernel/trace/bpf_trace.c | 4 ++++ > 10 files changed, 51 insertions(+), 72 deletions(-) > [...]
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