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 X-Spam-Level: X-Spam-Status: No, score=-11.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1127BC43464 for ; Fri, 18 Sep 2020 21:24:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C594A222BB for ; Fri, 18 Sep 2020 21:24:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600464245; bh=tFCykzw5FiQc4RWuWxh0kSdsBQlSn4+/zmJyGmIFFuA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=sKYCnkcCJ/ifSyTbOivtCHi2mAKb0TH2QRXjVW9XxzSfA9/nuhfKMhhCJKepEQFsi qyAPVxGuHELAIOMKYy2G9zgwR+tZ/09t9e2tdTVh4RsihQ9nzT7LVda+lFZrKkc6WT VDBqxhl0dKyGbuGozYfcuVIkxmA6joWlpLt+CSE8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726315AbgIRVYF (ORCPT ); Fri, 18 Sep 2020 17:24:05 -0400 Received: from mail.kernel.org ([198.145.29.99]:35810 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726305AbgIRVYF (ORCPT ); Fri, 18 Sep 2020 17:24:05 -0400 Received: from quaco.ghostprotocols.net (unknown [179.97.37.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 54EB322208; Fri, 18 Sep 2020 21:24:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1600464244; bh=tFCykzw5FiQc4RWuWxh0kSdsBQlSn4+/zmJyGmIFFuA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Z6zRW44ho6C62qq5aKJfi+JV/DyV9xrWuUZ5lxoBNmpL8uTccRfAJQ5omXsCnfXSZ 1xSFWRINRSKl5qPsg4rN/K29dhLeAYBn4zAlX7YlkIA2nJgMUqMMF5Vhg6kSK5TeWL d4BJPZ/fdmk+26zHGrtzTiF1Rc+mW8LbC7rn6aCI= Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id 3B76C400E9; Fri, 18 Sep 2020 18:24:02 -0300 (-03) Date: Fri, 18 Sep 2020 18:24:02 -0300 From: Arnaldo Carvalho de Melo To: Hao Luo Cc: Arnaldo Carvalho de Melo , Andrii Nakryiko , Alexei Starovoitov , daniel@iogearbox.net, dwarves@vger.kernel.org, yhs@fb.com Subject: Re: [PATCH 1/2] btf_encoder: Make encoding vars into BTF optional. Message-ID: <20200918212402.GE1996959@kernel.org> References: <20200918204058.1030519-1-haoluo@google.com> <20200918204058.1030519-2-haoluo@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200918204058.1030519-2-haoluo@google.com> X-Url: http://acmel.wordpress.com Precedence: bulk List-ID: X-Mailing-List: dwarves@vger.kernel.org Em Fri, Sep 18, 2020 at 01:40:57PM -0700, Hao Luo escreveu: > Introduce an option --btf_encode_symbols to pahole so that pahole > will only encode global symbols upon request. On the kernel side, > we can add a Kconfig to turn on this feature. This would make the > rollout of pahole v1.18 safe against potential bugs in the feature > introduced in commit f3d9054ba8ff ("btf_encoder: Teach pahole to > store percpu variables in vmlinux BTF."). 'encode_symbols' is too generic, please rename it to encode_global_symbols or something like that. - Arnaldo > Signed-off-by: Hao Luo > --- > btf_encoder.c | 5 ++++- > btf_encoder.h | 2 +- > pahole.c | 11 ++++++++++- > 3 files changed, 15 insertions(+), 3 deletions(-) > > diff --git a/btf_encoder.c b/btf_encoder.c > index 982f59d..54ffdd1 100644 > --- a/btf_encoder.c > +++ b/btf_encoder.c > @@ -237,7 +237,7 @@ static struct variable *hashaddr__find_variable(const struct hlist_head hashtabl > return NULL; > } > > -int cu__encode_btf(struct cu *cu, int verbose, bool force) > +int cu__encode_btf(struct cu *cu, int verbose, bool force, bool encode_symbols) > { > bool add_index_type = false; > uint32_t type_id_off; > @@ -314,6 +314,9 @@ int cu__encode_btf(struct cu *cu, int verbose, bool force) > } > } > > + /* if there is no request to encode symbols, just finish. */ > + if (!encode_symbols) > + goto out; > > if (btfe->percpu_shndx == 0 || !btfe->symtab) > goto out; > diff --git a/btf_encoder.h b/btf_encoder.h > index bca2348..f2e95fe 100644 > --- a/btf_encoder.h > +++ b/btf_encoder.h > @@ -13,6 +13,6 @@ struct cu; > > int btf_encoder__encode(); > > -int cu__encode_btf(struct cu *cu, int verbose, bool force); > +int cu__encode_btf(struct cu *cu, int verbose, bool force, bool encode_symbols); > > #endif /* _BTF_ENCODER_H_ */ > diff --git a/pahole.c b/pahole.c > index e1cde61..079d951 100644 > --- a/pahole.c > +++ b/pahole.c > @@ -26,6 +26,7 @@ > static bool btf_encode; > static bool ctf_encode; > static bool first_obj_only; > +static bool btf_encode_symbols; > > static uint8_t class__include_anonymous; > static uint8_t class__include_nested_anonymous; > @@ -809,6 +810,7 @@ ARGP_PROGRAM_VERSION_HOOK_DEF = dwarves_print_version; > #define ARGP_header_type 314 > #define ARGP_size_bytes 315 > #define ARGP_range 316 > +#define ARGP_btf_encode_symbols 317 > > static const struct argp_option pahole__options[] = { > { > @@ -1087,6 +1089,11 @@ static const struct argp_option pahole__options[] = { > .key = 'J', > .doc = "Encode as BTF", > }, > + { > + .name = "btf_encode_symbols", > + .key = ARGP_btf_encode_symbols, > + .doc = "Encode global symbols in BTF. Off by default." > + }, > { > .name = "force", > .key = 'j', > @@ -1207,6 +1214,8 @@ static error_t pahole__options_parser(int key, char *arg, > conf.range = arg; break; > case ARGP_header_type: > conf.header_type = arg; break; > + case ARGP_btf_encode_symbols: > + btf_encode_symbols = true; break; > default: > return ARGP_ERR_UNKNOWN; > } > @@ -2352,7 +2361,7 @@ static enum load_steal_kind pahole_stealer(struct cu *cu, > goto filter_it; > > if (btf_encode) { > - cu__encode_btf(cu, global_verbose, force); > + cu__encode_btf(cu, global_verbose, force, btf_encode_symbols); > return LSK__KEEPIT; > } > > -- > 2.28.0.681.g6f77f65b4e-goog > -- - Arnaldo