Hi Kuohai, > On Sep 20, 2023, at 12:39 AM, Xu Kuohai <xukuohai@xxxxxxxxxx> wrote: > > Hi Song, > > On 9/20/2023 1:31 PM, Song Liu wrote: >> This helper will be used to calculate the size of the trampoline before >> allocating the memory. >> Signed-off-by: Song Liu <song@xxxxxxxxxx> >> --- [...] >> + >> + nregs = btf_func_model_nregs(m); >> + /* the first 8 registers are used for arguments */ >> + if (nregs > 8) >> + return -ENOTSUPP; >> + >> + ret = arch_bpf_trampoline_size(m, flags, tlinks, func_addr); >> + if (ret < 0) >> + return ret; > > Since arch_bpf_trampoline_size was already called before the trampoline > image was allocated, it seems this call to arch_bpf_trampoline_size is > unnecessary. If this call can be omitted, we can avoid one less dry run. Indeed. This set doesn't call arch_bpf_trampoline_size() from struct_ops. But we can add that and then remove the _size() call here. Thanks, Song > >> + >> + if (ret > ((long)image_end - (long)image)) >> + return -EFBIG; >> jit_fill_hole(image, (unsigned int)(image_end - image)); >> ret = prepare_trampoline(&ctx, im, tlinks, func_addr, nregs, flags); > > > [...] >
