Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751840AbcDZNrz (ORCPT ); Tue, 26 Apr 2016 09:47:55 -0400 Received: from mail.kernel.org ([198.145.29.136]:39862 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751858AbcDZNry (ORCPT ); Tue, 26 Apr 2016 09:47:54 -0400 Date: Tue, 26 Apr 2016 10:47:49 -0300 From: Arnaldo Carvalho de Melo To: Masami Hiramatsu Cc: linux-kernel@vger.kernel.org, Namhyung Kim , Peter Zijlstra , Ingo Molnar , Hemant Kumar , Ananth N Mavinakayanahalli Subject: Re: [PATCH perf/core v4 03/19] perf buildid-cache: Fall back to the old style build-id cache Message-ID: <20160426134749.GB20998@kernel.org> References: <20160426090200.11891.43944.stgit@devbox> <20160426090233.11891.70554.stgit@devbox> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160426090233.11891.70554.stgit@devbox> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3777 Lines: 107 Em Tue, Apr 26, 2016 at 06:02:33PM +0900, Masami Hiramatsu escreveu: > Fall back to the old style build-id cache > (~/.debug//) if possible. > Because there is old build-id cache under ~/.debug, perf > has to check if the old entry is there instead of returning > an error. Or, user have to remove ~/.debug completely. So, from the description this seems to address the issues I mentioned in the previous patch. Probably it is a good idea not to introduce the problem in the first place? I.e. combine this and the previous patch, so that we don't have this bisection break? - Arnaldo > This patch introduces fallback code to try using old-style > buildid caches. To update the cached entry, you just need to > add a cache. It automatically removes old cache entry and > make a new one in new style > (~/.debug///[elf|vdso|kallsyms]). > > IOW, without this patch, "perf buildid-cache --add" always > gets errors when adding existing binaries. > ---- > # perf buildid-cache -a /usr/lib64/libc-2.20.so,/usr/bin/gcc > Couldn't add /usr/bin/gcc: Not a directory > Couldn't add /usr/lib64/libc-2.20.so: Not a directory > ---- > Moreover, --update option removes only symlink, thus the > build-id cache is corrupted. > > This fixes above issues. > > Signed-off-by: Masami Hiramatsu > --- > tools/perf/util/build-id.c | 17 ++++++++++++++++- > tools/perf/util/symbol.c | 13 +++++++++---- > 2 files changed, 25 insertions(+), 5 deletions(-) > > diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c > index 46a8bcc..b035483 100644 > --- a/tools/perf/util/build-id.c > +++ b/tools/perf/util/build-id.c > @@ -155,6 +155,12 @@ static char *build_id_cache__linkname(const char *sbuild_id, char *bf, > return bf; > } > > +static bool __is_regular_file(const char *pathname) > +{ > + struct stat sb; > + return stat(pathname, &sb) == 0 && S_ISREG(sb.st_mode); > +} > + > static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso) > { > return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : "elf"); > @@ -177,7 +183,11 @@ char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size) > if (!linkname) > return NULL; > > - ret = asnprintf(&bf, size, "%s/%s", linkname, > + /* Check if old style build_id cache */ > + if (__is_regular_file(linkname)) > + ret = asnprintf(&bf, size, "%s", linkname); > + else > + ret = asnprintf(&bf, size, "%s/%s", linkname, > build_id_cache__basename(is_kallsyms, is_vdso)); > if (ret < 0 || (!alloc && size < (unsigned int)ret)) > bf = NULL; > @@ -445,6 +455,11 @@ int build_id_cache__add_s(const char *sbuild_id, const char *name, > if (!dir_name) > goto out_free; > > + /* Remove old style build-id cache */ > + if (__is_regular_file(dir_name)) > + if (unlink(dir_name)) > + goto out_free; > + > if (mkdir_p(dir_name, 0755)) > goto out_free; > > diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c > index c57cb47..9463c7d 100644 > --- a/tools/perf/util/symbol.c > +++ b/tools/perf/util/symbol.c > @@ -1687,11 +1687,16 @@ static char *dso__find_kallsyms(struct dso *dso, struct map *map) > > scnprintf(path, sizeof(path), "%s/[kernel.kallsyms]/%s/kallsyms", > buildid_dir, sbuild_id); > - > + /* Try old style kallsyms cache */ > if (access(path, F_OK)) { > - pr_err("No kallsyms or vmlinux with build-id %s was found\n", > - sbuild_id); > - return NULL; > + scnprintf(path, sizeof(path), "%s/[kernel.kallsyms]/%s", > + buildid_dir, sbuild_id); > + > + if (access(path, F_OK)) { > + pr_err("No kallsyms or vmlinux with build-id %s was found\n", > + sbuild_id); > + return NULL; > + } > } > > return strdup(path);