From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 37E2CC4332F for ; Mon, 18 Apr 2022 15:29:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243129AbiDRPbe (ORCPT ); Mon, 18 Apr 2022 11:31:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38528 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242574AbiDRPav (ORCPT ); Mon, 18 Apr 2022 11:30:51 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 635013467A; Mon, 18 Apr 2022 07:40:00 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id EAD0660FA4; Mon, 18 Apr 2022 14:39:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D08C4C385A1; Mon, 18 Apr 2022 14:39:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1650292799; bh=lVGjQiNeitfHX6Iw3+yTxPJF2qVLbXbZLtivn9dL8HI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Z/3j0DiSUf+Ao6nkd41yapgoBbFIJGGLFAkGZWMBukANcXiLbbN6qlE+ZtGtrK9wi qMUr8KUKJdRbWUxALTxU9dWV+wIkGsBP+7vIOu7mhvF4FHBh7h6hPibFIvyqCNNgyw NbvNm2+zYu0nJ4FKDHHAZkL1QcSbRlgitn7o61GqJMkFkUX8JpxzHMXjPRQNelSPra k9N3GIkbV1JHNmLtCJf7k+g+3qVmToVyc0SFJ0AKzhgTmPZcGiEt711efcEAH4Z9Tt PoUt2rI2OAfO1klT+lQQ4jOohCyWm5HPcIXFoIdd1/FgTbhsj8noS3Zy+AkRfQ65lJ HkYxc7fSmXIXA== Date: Mon, 18 Apr 2022 23:39:54 +0900 From: Masami Hiramatsu To: Jiri Olsa Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , netdev@vger.kernel.org, bpf@vger.kernel.org, lkml , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh Subject: Re: [PATCHv2 bpf-next 2/4] fprobe: Resolve symbols with kallsyms_lookup_names Message-Id: <20220418233954.0b17b003759d54b81e78888b@kernel.org> In-Reply-To: <20220418124834.829064-3-jolsa@kernel.org> References: <20220418124834.829064-1-jolsa@kernel.org> <20220418124834.829064-3-jolsa@kernel.org> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Hi Jiri, On Mon, 18 Apr 2022 14:48:32 +0200 Jiri Olsa wrote: > Using kallsyms_lookup_names to speed up symbols lookup > in register_fprobe_syms API. > > This requires syms array to be alphabetically sorted. This looks good to me. But we may need to update this for changing the function name "kallsyms_lookup_names()". I think "ftrace_lookup_sorted_syms()" will be better to understand. What would you think? Thank you, > > Signed-off-by: Jiri Olsa > --- > kernel/trace/fprobe.c | 32 ++++++++++++-------------------- > 1 file changed, 12 insertions(+), 20 deletions(-) > > diff --git a/kernel/trace/fprobe.c b/kernel/trace/fprobe.c > index 89d9f994ebb0..6419501a0036 100644 > --- a/kernel/trace/fprobe.c > +++ b/kernel/trace/fprobe.c > @@ -85,39 +85,31 @@ static void fprobe_exit_handler(struct rethook_node *rh, void *data, > } > NOKPROBE_SYMBOL(fprobe_exit_handler); > > +static int symbols_cmp(const void *a, const void *b) > +{ > + const char **str_a = (const char **) a; > + const char **str_b = (const char **) b; > + > + return strcmp(*str_a, *str_b); > +} > + > /* Convert ftrace location address from symbols */ > static unsigned long *get_ftrace_locations(const char **syms, int num) > { > - unsigned long addr, size; > unsigned long *addrs; > - int i; > > /* Convert symbols to symbol address */ > addrs = kcalloc(num, sizeof(*addrs), GFP_KERNEL); > if (!addrs) > return ERR_PTR(-ENOMEM); > > - for (i = 0; i < num; i++) { > - addr = kallsyms_lookup_name(syms[i]); > - if (!addr) /* Maybe wrong symbol */ > - goto error; > - > - /* Convert symbol address to ftrace location. */ > - if (!kallsyms_lookup_size_offset(addr, &size, NULL) || !size) > - goto error; > + /* kallsyms_lookup_names expects sorted symbols */ > + sort(syms, num, sizeof(*syms), symbols_cmp, NULL); > > - addr = ftrace_location_range(addr, addr + size - 1); > - if (!addr) /* No dynamic ftrace there. */ > - goto error; > + if (!kallsyms_lookup_names(syms, num, addrs)) > + return addrs; > > - addrs[i] = addr; > - } > - > - return addrs; > - > -error: > kfree(addrs); > - > return ERR_PTR(-ENOENT); > } > > -- > 2.35.1 > -- Masami Hiramatsu