Le 25/08/2023 à 17:18, Hari Bathini a écrit :
> Use the newly introduced patch_instructions() that handles patching
> multiple instructions with one call. This improves speed of exectution
> for JIT'ing bpf programs.
>
> Without this patch (on a POWER9 lpar):
>
> # time modprobe test_bpf
> real 2m59.681s
> user 0m0.000s
> sys 1m44.160s
> #
>
> With this patch (on a POWER9 lpar):
>
> # time modprobe test_bpf
> real 0m5.013s
> user 0m0.000s
> sys 0m4.216s
> #
Right, significant improvement. Forget by comment to patch 1, I should
have read the series up to the end. Just wondering why you don't just
put patch 4 up front ?
Christophe
>
> Signed-off-by: Hari Bathini <hbathini@xxxxxxxxxxxxx>
> ---
> arch/powerpc/net/bpf_jit_comp.c | 30 ++++--------------------------
> 1 file changed, 4 insertions(+), 26 deletions(-)
>
> diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
> index c60d7570e05d..1e5000d18321 100644
> --- a/arch/powerpc/net/bpf_jit_comp.c
> +++ b/arch/powerpc/net/bpf_jit_comp.c
> @@ -26,28 +26,6 @@ static void bpf_jit_fill_ill_insns(void *area, unsigned int size)
> memset32(area, BREAKPOINT_INSTRUCTION, size / 4);
> }
>
> -/*
> - * Patch 'len' bytes of instructions from opcode to addr, one instruction
> - * at a time. Returns addr on success. ERR_PTR(-EINVAL), otherwise.
> - */
> -static void *bpf_patch_instructions(void *addr, void *opcode, size_t len, bool fill_insn)
> -{
> - while (len > 0) {
> - ppc_inst_t insn = ppc_inst_read(opcode);
> - int ilen = ppc_inst_len(insn);
> -
> - if (patch_instruction(addr, insn))
> - return ERR_PTR(-EINVAL);
> -
> - len -= ilen;
> - addr = addr + ilen;
> - if (!fill_insn)
> - opcode = opcode + ilen;
> - }
> -
> - return addr;
> -}
> -
> int bpf_jit_emit_exit_insn(u32 *image, struct codegen_context *ctx, int tmp_reg, long exit_addr)
> {
> if (!exit_addr || is_offset_in_branch_range(exit_addr - (ctx->idx * 4))) {
> @@ -330,16 +308,16 @@ int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image, u32 *fimage, int pass
>
> void *bpf_arch_text_copy(void *dst, void *src, size_t len)
> {
> - void *ret;
> + int err;
>
> if (WARN_ON_ONCE(core_kernel_text((unsigned long)dst)))
> return ERR_PTR(-EINVAL);
>
> mutex_lock(&text_mutex);
> - ret = bpf_patch_instructions(dst, src, len, false);
> + err = patch_instructions(dst, src, len, false);
> mutex_unlock(&text_mutex);
>
> - return ret;
> + return err ? ERR_PTR(err) : dst;
> }
>
> int bpf_arch_text_invalidate(void *dst, size_t len)
> @@ -351,7 +329,7 @@ int bpf_arch_text_invalidate(void *dst, size_t len)
> return -EINVAL;
>
> mutex_lock(&text_mutex);
> - ret = IS_ERR(bpf_patch_instructions(dst, &insn, len, true));
> + ret = patch_instructions(dst, &insn, len, true);
> mutex_unlock(&text_mutex);
>
> return ret;
