From: Alexei Starovoitov <alexei.starovoi...@gmail.com> Date: Fri, 30 Nov 2018 13:58:20 -0800
> On Thu, Nov 29, 2018 at 07:32:41PM -0800, David Miller wrote: >> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h >> index 426b5c8..c9647ea 100644 >> --- a/include/uapi/linux/bpf.h >> +++ b/include/uapi/linux/bpf.h >> @@ -232,6 +232,16 @@ enum bpf_attach_type { >> */ >> #define BPF_F_STRICT_ALIGNMENT (1U << 0) >> >> +/* If BPF_F_ANY_ALIGNMENT is used in BPF_PROF_LOAD command, the >> + * verifier will allow any alignment whatsoever. This bypasses >> + * what CONFIG_EFFICIENT_UNALIGNED_ACCESS would cause it to do. > > I think majority of user space folks who read uapi/bpf.h have no idea > what that kernel config does. > Could you reword the comment here to say that this flag is only > effective on architectures and like sparc and mips that don't > have efficient unaligned access and ignored on x86/arm64 ? I just want to point out in passing that your feeback applies also to the comment above BPF_F_STRICT_ALIGNMENT, which I used as a model for my comment.