RE: [PATCH v2 bpf-next 3/3] bpf: remove unnecessary prune and jump points

[John Fastabend <john.fastabend@gmail.com>]

Andrii Nakryiko wrote:
> Don't mark some instructions as jump points when there are actually no
> jumps and instructions are just processed sequentially. Such case is
> handled naturally by precision backtracking logic without the need to
> update jump history. See get_prev_insn_idx(). It goes back linearly by
> one instruction, unless current top of jmp_history is pointing to
> current instruction. In such case we use `st->jmp_history[cnt - 1].prev_idx`
> to find instruction from which we jumped to the current instruction
> non-linearly.
> 
> Also remove both jump and prune point marking for instruction right
> after unconditional jumps, as program flow can get to the instruction
> right after unconditional jump instruction only if there is a jump to
> that instruction from somewhere else in the program. In such case we'll
> mark such instruction as prune/jump point because it's a destination of
> a jump.
> 
> This change has no changes in terms of number of instructions or states
> processes across Cilium and selftests programs.
> 
> Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
> ---

Thanks.

Acked-by: John Fastabend <john.fastabend@gmail.com>