From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752684AbaA2TPD (ORCPT ); Wed, 29 Jan 2014 14:15:03 -0500 Received: from mail-yk0-f170.google.com ([209.85.160.170]:62922 "EHLO mail-yk0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751519AbaA2TPB (ORCPT ); Wed, 29 Jan 2014 14:15:01 -0500 Date: Wed, 29 Jan 2014 16:14:54 -0300 From: Arnaldo Carvalho de Melo To: Adrian Hunter Cc: Peter Zijlstra , Ingo Molnar , linux-kernel@vger.kernel.org, David Ahern , Frederic Weisbecker , Jiri Olsa , Mike Galbraith , Namhyung Kim , Paul Mackerras , Stephane Eranian Subject: Re: [PATCH V2 9/9] perf buildid-cache: Check relocation when checking for existing kcore Message-ID: <20140129191454.GG3998@ghostprotocols.net> References: <1391004884-10334-1-git-send-email-adrian.hunter@intel.com> <1391004884-10334-10-git-send-email-adrian.hunter@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1391004884-10334-10-git-send-email-adrian.hunter@intel.com> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Em Wed, Jan 29, 2014 at 04:14:44PM +0200, Adrian Hunter escreveu: > perf buildid-cache does not make another > copy of kcore if the buildid and modules > match an existing copy. That does not Humm, what is the problem? Having the ref reloc symbol we can fix things up, no? I.e. just using map->reloc the old kcore copy should be ok to use, no need to replace the kcore copy in the cache. Or am I missing something? - Arnaldo > take into account the possibility that > the kernel has been relocated. Extend > the check to check if the reference > relocation symbol matches too, otherwise > do make a copy. > > Signed-off-by: Adrian Hunter > --- > tools/perf/builtin-buildid-cache.c | 33 +++++++++++++++++++++++++++++---- > 1 file changed, 29 insertions(+), 4 deletions(-) > > diff --git a/tools/perf/builtin-buildid-cache.c b/tools/perf/builtin-buildid-cache.c > index cfede86..b22dbb1 100644 > --- a/tools/perf/builtin-buildid-cache.c > +++ b/tools/perf/builtin-buildid-cache.c > @@ -63,11 +63,35 @@ static int build_id_cache__kcore_dir(char *dir, size_t sz) > return 0; > } > > +static bool same_kallsyms_reloc(const char *from_dir, char *to_dir) > +{ > + char from[PATH_MAX]; > + char to[PATH_MAX]; > + const char *name; > + u64 addr1 = 0, addr2 = 0; > + int i; > + > + scnprintf(from, sizeof(from), "%s/kallsyms", from_dir); > + scnprintf(to, sizeof(to), "%s/kallsyms", to_dir); > + > + for (i = 0; (name = ref_reloc_sym_names[i]) != NULL; i++) { > + addr1 = kallsyms__get_function_start(from, name); > + if (addr1) > + break; > + } > + > + if (name) > + addr2 = kallsyms__get_function_start(to, name); > + > + return addr1 == addr2; > +} > + > static int build_id_cache__kcore_existing(const char *from_dir, char *to_dir, > size_t to_dir_sz) > { > char from[PATH_MAX]; > char to[PATH_MAX]; > + char to_subdir[PATH_MAX]; > struct dirent *dent; > int ret = -1; > DIR *d; > @@ -86,10 +110,11 @@ static int build_id_cache__kcore_existing(const char *from_dir, char *to_dir, > continue; > scnprintf(to, sizeof(to), "%s/%s/modules", to_dir, > dent->d_name); > - if (!compare_proc_modules(from, to)) { > - scnprintf(to, sizeof(to), "%s/%s", to_dir, > - dent->d_name); > - strlcpy(to_dir, to, to_dir_sz); > + scnprintf(to_subdir, sizeof(to_subdir), "%s/%s", > + to_dir, dent->d_name); > + if (!compare_proc_modules(from, to) && > + same_kallsyms_reloc(from_dir, to_subdir)) { > + strlcpy(to_dir, to_subdir, to_dir_sz); > ret = 0; > break; > } > -- > 1.7.11.7