| Message ID | 20210107041801.2003241-1-songliubraving@fb.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | introduce bpf_iter for task_vma | expand |
On Thu, Jan 7, 2021 at 5:23 AM Song Liu <songliubraving@fb.com> wrote: > > task_file and task_vma iter programs have access to file->f_path. Enable > bpf_d_path to print paths of these file. > > bpf_iter programs are generally called in sleepable context. However, it > is still necessary to diffientiate sleepable and non-sleepable bpf_iter > programs: sleepable programs have access to bpf_d_path; non-sleepable > programs have access to bpf_spin_lock. > > Acked-by: Yonghong Song <yhs@fb.com> > Signed-off-by: Song Liu <songliubraving@fb.com> Acked-by: KP Singh <kpsingh@kernel.org>
This set introduces bpf_iter for task_vma, which can be used to generate information similar to /proc/pid/maps. Patch 4/4 adds an example that mimics /proc/pid/maps. Current /proc/<pid>/maps and /proc/<pid>/smaps provide information of vma's of a process. However, these information are not flexible enough to cover all use cases. For example, if a vma cover mixed 2MB pages and 4kB pages (x86_64), there is no easy way to tell which address ranges are backed by 2MB pages. task_vma solves the problem by enabling the user to generate customize information based on the vma (and vma->vm_mm, vma->vm_file, etc.). Changes v2 => v3: 1. Rewrite 1/4 so that we hold mmap_lock while calling BPF program. This enables the BPF program to access the real vma with BTF. (Alexei) 2. Fix the logic when the control is returned to user space. (Yonghong) 3. Revise commit log and cover letter. (Yonghong) Changes v1 => v2: 1. Small fixes in task_iter.c and the selftests. (Yonghong) Song Liu (4): bpf: introduce task_vma bpf_iter bpf: allow bpf_d_path in sleepable bpf_iter program libbpf: introduce section "iter.s/" for sleepable bpf_iter program selftests/bpf: add test for bpf_iter_task_vma kernel/bpf/task_iter.c | 212 +++++++++++++++++- kernel/trace/bpf_trace.c | 5 + tools/lib/bpf/libbpf.c | 5 + .../selftests/bpf/prog_tests/bpf_iter.c | 114 +++++++++- tools/testing/selftests/bpf/progs/bpf_iter.h | 8 + .../selftests/bpf/progs/bpf_iter_task_vma.c | 58 +++++ 6 files changed, 391 insertions(+), 11 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/bpf_iter_task_vma.c -- 2.24.1