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| author | Alexei Starovoitov <ast@kernel.org> | 2024-04-04 13:08:01 -0700 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2024-04-04 13:08:01 -0700 |
| commit | d82c045f9dfde6b9ea220d7f8310c98210dfc8cb (patch) | |
| tree | 05376a14c790f914df2197a0431c3608ac025e66 /kernel/trace | |
| parent | bpf, riscv: Implement bpf_addr_space_cast instruction (diff) | |
| parent | bpf: inline bpf_get_branch_snapshot() helper (diff) | |
| download | linux-d82c045f9dfde6b9ea220d7f8310c98210dfc8cb.tar.gz linux-d82c045f9dfde6b9ea220d7f8310c98210dfc8cb.zip | |
Merge branch 'inline-bpf_get_branch_snapshot-bpf-helper'
Andrii Nakryiko says:
====================
Inline bpf_get_branch_snapshot() BPF helper
Implement inlining of bpf_get_branch_snapshot() BPF helper using generic BPF
assembly approach. This allows to reduce LBR record usage right before LBR
records are captured from inside BPF program.
See v1 cover letter ([0]) for some visual examples. I dropped them from v2
because there are multiple independent changes landing and being reviewed, all
of which remove different parts of LBR record waste, so presenting final state
of LBR "waste" gets more complicated until all of the pieces land.
[0] https://lore.kernel.org/bpf/20240321180501.734779-1-andrii@kernel.org/
v2->v3:
- fix BPF_MUL instruction definition;
v1->v2:
- inlining of bpf_get_smp_processor_id() split out into a separate patch set
implementing internal per-CPU BPF instruction;
- add efficient divide-by-24 through multiplication logic, and leave
comments to explain the idea behind it; this way inlined version of
bpf_get_branch_snapshot() has no compromises compared to non-inlined
version of the helper (Alexei).
====================
Link: https://lore.kernel.org/r/20240404002640.1774210-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/trace')
| -rw-r--r-- | kernel/trace/bpf_trace.c | 4 |
1 files changed, 0 insertions, 4 deletions
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 6d0c95638e1b..afb232b1d7c2 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -1188,9 +1188,6 @@ static const struct bpf_func_proto bpf_get_attach_cookie_proto_tracing = { BPF_CALL_3(bpf_get_branch_snapshot, void *, buf, u32, size, u64, flags) { -#ifndef CONFIG_X86 - return -ENOENT; -#else static const u32 br_entry_size = sizeof(struct perf_branch_entry); u32 entry_cnt = size / br_entry_size; @@ -1203,7 +1200,6 @@ BPF_CALL_3(bpf_get_branch_snapshot, void *, buf, u32, size, u64, flags) return -ENOENT; return entry_cnt * br_entry_size; -#endif } static const struct bpf_func_proto bpf_get_branch_snapshot_proto = { |