On 8/28/20 12:01 AM, Alexei Starovoitov wrote:
From: Alexei Starovoitov <ast@xxxxxxxxxx>
v2->v3:
- switched to minimal allowlist approach. Essentially that means that syscall
entry, few btrfs allow_error_inject functions, should_fail_bio(), and two LSM
hooks: file_mprotect and bprm_committed_creds are the only hooks that allow
attaching of sleepable BPF programs. When comprehensive analysis of LSM hooks
will be done this allowlist will be extended.
- added patch 1 that fixes prototypes of two mm functions to reliably work with
error injection. It's also necessary for resolve_btfids tool to recognize
these two funcs, but that's secondary.
v1->v2:
- split fmod_ret fix into separate patch
- added denylist
v1:
This patch set introduces the minimal viable support for sleepable bpf programs.
In this patch only fentry/fexit/fmod_ret and lsm progs can be sleepable.
Only array and pre-allocated hash and lru maps allowed.
Here is 'perf report' difference of sleepable vs non-sleepable:
3.86% bench [k] __srcu_read_unlock
3.22% bench [k] __srcu_read_lock
0.92% bench [k] bpf_prog_740d4210cdcd99a3_bench_trigger_fentry_sleep
0.50% bench [k] bpf_trampoline_10297
0.26% bench [k] __bpf_prog_exit_sleepable
0.21% bench [k] __bpf_prog_enter_sleepable
vs
0.88% bench [k] bpf_prog_740d4210cdcd99a3_bench_trigger_fentry
0.84% bench [k] bpf_trampoline_10297
0.13% bench [k] __bpf_prog_enter
0.12% bench [k] __bpf_prog_exit
vs
0.79% bench [k] bpf_prog_740d4210cdcd99a3_bench_trigger_fentry_sleep
0.72% bench [k] bpf_trampoline_10381
0.31% bench [k] __bpf_prog_exit_sleepable
0.29% bench [k] __bpf_prog_enter_sleepable
Sleepable vs non-sleepable program invocation overhead is only marginally higher
due to rcu_trace. srcu approach is much slower.
Alexei Starovoitov (5):
mm/error_inject: Fix allow_error_inject function signatures.
bpf: Introduce sleepable BPF programs
bpf: Add bpf_copy_from_user() helper.
libbpf: support sleepable progs
selftests/bpf: Add sleepable tests
arch/x86/net/bpf_jit_comp.c | 32 +++++---
include/linux/bpf.h | 4 +
include/uapi/linux/bpf.h | 16 ++++
init/Kconfig | 1 +
kernel/bpf/arraymap.c | 1 +
kernel/bpf/hashtab.c | 12 +--
kernel/bpf/helpers.c | 22 +++++
kernel/bpf/syscall.c | 13 ++-
kernel/bpf/trampoline.c | 28 ++++++-
kernel/bpf/verifier.c | 81 ++++++++++++++++++-
kernel/trace/bpf_trace.c | 2 +
mm/filemap.c | 8 +-
mm/page_alloc.c | 2 +-
tools/include/uapi/linux/bpf.h | 16 ++++
tools/lib/bpf/libbpf.c | 25 +++++-
tools/testing/selftests/bpf/bench.c | 2 +
.../selftests/bpf/benchs/bench_trigger.c | 17 ++++
.../selftests/bpf/prog_tests/test_lsm.c | 9 +++
tools/testing/selftests/bpf/progs/lsm.c | 66 ++++++++++++++-
.../selftests/bpf/progs/trigger_bench.c | 7 ++
20 files changed, 331 insertions(+), 33 deletions(-)
Applied, thanks!
