| Message ID | 20230912070149.969939-1-zhouchuyi@bytedance.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | Add Open-coded process and css iters | expand |
在 2023/9/12 15:01, Chuyi Zhou 写道: > Hi, > > This is version 2 of process and css iters support. All the changes were > suggested by Alexei. > > Thanks for your review! > > --- Changelog --- > Changes from v1: > - Add a pre-patch to make some preparations before supporting css_task > iters. > - Add an allowlist for css_task iters > - Let bpf progs do explicit bpf_rcu_read_lock() when using process iters > and css_descendant iters. Sorry for missing the link to v1 (https://lore.kernel.org/lkml/20230827072057.1591929-1-zhouchuyi@bytedance.com/). > --------------------- > > In some BPF usage scenarios, it will be useful to iterate the process and > css directly in the BPF program. One of the expected scenarios is > customizable OOM victim selection via BPF[1]. > > Inspired by Dave's task_vma iter[2], this patchset adds three types of > open-coded iterator kfuncs: > > 1. bpf_for_each(process, p). Just like for_each_process(p) in kernel to > itearing all tasks in the system. > > 2. bpf_for_each(css_task, task, css). It works like > css_task_iter_{start, next, end} and would be used to iterating > tasks/threads under a css. > > 3. bpf_for_each(css_{post, pre}, pos, root_css). It works like > css_next_descendant_{pre, post} to iterating all descendant css. > > BPF programs can use these kfuncs directly or through bpf_for_each macro. > > link[1]: https://lore.kernel.org/lkml/20230810081319.65668-1-zhouchuyi@bytedance.com/ > link[2]: https://lore.kernel.org/all/20230810183513.684836-1-davemarchevsky@fb.com/ > > Chuyi Zhou (6): > cgroup: Prepare for using css_task_iter_*() in BPF > bpf: Introduce css_task open-coded iterator kfuncs > bpf: Introduce process open coded iterator kfuncs > bpf: Introduce css_descendant open-coded iterator kfuncs > bpf: teach the verifier to enforce css_iter and process_iter in RCU CS > selftests/bpf: Add tests for open-coded task and css iter > > include/linux/cgroup.h | 12 +- > include/uapi/linux/bpf.h | 16 ++ > kernel/bpf/helpers.c | 12 ++ > kernel/bpf/task_iter.c | 130 +++++++++++++++++ > kernel/bpf/verifier.c | 53 ++++++- > kernel/cgroup/cgroup.c | 18 ++- > tools/include/uapi/linux/bpf.h | 16 ++ > tools/lib/bpf/bpf_helpers.h | 24 +++ > .../testing/selftests/bpf/prog_tests/iters.c | 138 ++++++++++++++++++ > .../testing/selftests/bpf/progs/iters_task.c | 104 +++++++++++++ > 10 files changed, 508 insertions(+), 15 deletions(-) > create mode 100644 tools/testing/selftests/bpf/progs/iters_task.c >
Hi, This is version 2 of process and css iters support. All the changes were suggested by Alexei. Thanks for your review! --- Changelog --- Changes from v1: - Add a pre-patch to make some preparations before supporting css_task iters. - Add an allowlist for css_task iters - Let bpf progs do explicit bpf_rcu_read_lock() when using process iters and css_descendant iters. --------------------- In some BPF usage scenarios, it will be useful to iterate the process and css directly in the BPF program. One of the expected scenarios is customizable OOM victim selection via BPF[1]. Inspired by Dave's task_vma iter[2], this patchset adds three types of open-coded iterator kfuncs: 1. bpf_for_each(process, p). Just like for_each_process(p) in kernel to itearing all tasks in the system. 2. bpf_for_each(css_task, task, css). It works like css_task_iter_{start, next, end} and would be used to iterating tasks/threads under a css. 3. bpf_for_each(css_{post, pre}, pos, root_css). It works like css_next_descendant_{pre, post} to iterating all descendant css. BPF programs can use these kfuncs directly or through bpf_for_each macro. link[1]: https://lore.kernel.org/lkml/20230810081319.65668-1-zhouchuyi@bytedance.com/ link[2]: https://lore.kernel.org/all/20230810183513.684836-1-davemarchevsky@fb.com/ Chuyi Zhou (6): cgroup: Prepare for using css_task_iter_*() in BPF bpf: Introduce css_task open-coded iterator kfuncs bpf: Introduce process open coded iterator kfuncs bpf: Introduce css_descendant open-coded iterator kfuncs bpf: teach the verifier to enforce css_iter and process_iter in RCU CS selftests/bpf: Add tests for open-coded task and css iter include/linux/cgroup.h | 12 +- include/uapi/linux/bpf.h | 16 ++ kernel/bpf/helpers.c | 12 ++ kernel/bpf/task_iter.c | 130 +++++++++++++++++ kernel/bpf/verifier.c | 53 ++++++- kernel/cgroup/cgroup.c | 18 ++- tools/include/uapi/linux/bpf.h | 16 ++ tools/lib/bpf/bpf_helpers.h | 24 +++ .../testing/selftests/bpf/prog_tests/iters.c | 138 ++++++++++++++++++ .../testing/selftests/bpf/progs/iters_task.c | 104 +++++++++++++ 10 files changed, 508 insertions(+), 15 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/iters_task.c