From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755536AbbIXNmr (ORCPT ); Thu, 24 Sep 2015 09:42:47 -0400 Received: from mail.kernel.org ([198.145.29.136]:34195 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753378AbbIXNmp (ORCPT ); Thu, 24 Sep 2015 09:42:45 -0400 Date: Thu, 24 Sep 2015 10:42:28 -0300 From: Arnaldo Carvalho de Melo To: Namhyung Kim Cc: Adrian Hunter , Borislav Petkov , David Ahern , Frederic Weisbecker , Jiri Olsa , Stephane Eranian , Wang Nan , Ingo Molnar , Linux Kernel Mailing List Subject: [PATCH/RFC] perf buildid: Cache kernel DSO created when reading buildid header table Message-ID: <20150924134228.GJ1897@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Namhyung, Can you take a look and perhaps give me your Acked-by? - Arnaldo From: Arnaldo Carvalho de Melo No need to traverse it all again using the filename extension to disambiguate kernel from kernel modules, just cache it when reading the buildid table. This also fixes a refcount bug in the error path, i.e. in the error path for the __machine__create_kernel_maps() call we do a dso__put(), which is ok and expected if that dso came from machine__findnew_dso(), but wasn't when we found it by traversing the machine dso list without grabbing a dso refcount (dso__get()) before dropping the list lock. Fixes: b837a8bdc489 ("perf tools: Fix build-id matching on vmlinux") Link: http://lkml.kernel.org/n/tip-48fh3cf6pvs4zs2fj4nhc4b5@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/header.c | 7 +++++++ tools/perf/util/machine.c | 34 +++------------------------------- tools/perf/util/machine.h | 1 + 3 files changed, 11 insertions(+), 31 deletions(-) diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 43838003c1a1..6bc92ae1e99a 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -1260,6 +1260,13 @@ static int __event_process_build_id(struct build_id_event *bev, if (!is_kernel_module(filename, cpumode)) dso->kernel = dso_type; + /* + * We don't need to grab a reference as long as + * the kernel dso is in the machine dso list. + */ + if (cpumode == PERF_RECORD_MISC_KERNEL || + cpumode == PERF_RECORD_MISC_GUEST_KERNEL) + machine->kernel_dso = dso; build_id__sprintf(dso->build_id, sizeof(dso->build_id), sbuild_id); diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index d07a38678e14..f6e689b2c83c 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -62,6 +62,7 @@ int machine__init(struct machine *machine, const char *root_dir, pid_t pid) } machine->current_tid = NULL; + machine->kernel_dso = NULL; return 0; } @@ -1180,39 +1181,10 @@ static int machine__process_kernel_mmap_event(struct machine *machine, * Should be there already, from the build-id table in * the header. */ - struct dso *kernel = NULL; - struct dso *dso; + struct dso *kernel; pthread_rwlock_rdlock(&machine->dsos.lock); - - list_for_each_entry(dso, &machine->dsos.head, node) { - - /* - * The cpumode passed to is_kernel_module is not the - * cpumode of *this* event. If we insist on passing - * correct cpumode to is_kernel_module, we should - * record the cpumode when we adding this dso to the - * linked list. - * - * However we don't really need passing correct - * cpumode. We know the correct cpumode must be kernel - * mode (if not, we should not link it onto kernel_dsos - * list). - * - * Therefore, we pass PERF_RECORD_MISC_CPUMODE_UNKNOWN. - * is_kernel_module() treats it as a kernel cpumode. - */ - - if (!dso->kernel || - is_kernel_module(dso->long_name, - PERF_RECORD_MISC_CPUMODE_UNKNOWN)) - continue; - - - kernel = dso; - break; - } - + kernel = dso__get(machine->kernel_dso); pthread_rwlock_unlock(&machine->dsos.lock); if (kernel == NULL) diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h index 9dfc4281f940..d7b044a1046f 100644 --- a/tools/perf/util/machine.h +++ b/tools/perf/util/machine.h @@ -38,6 +38,7 @@ struct machine { struct dsos dsos; struct map_groups kmaps; struct map *vmlinux_maps[MAP__NR_TYPES]; + struct dso *kernel_dso; u64 kernel_start; symbol_filter_t symbol_filter; pid_t *current_tid; -- 2.1.0