Messages in this thread Patch in this message | | | Date | Thu, 24 Sep 2015 10:42:28 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | [PATCH/RFC] perf buildid: Cache kernel DSO created when reading buildid header table |
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Namhyung,
Can you take a look and perhaps give me your Acked-by?
- Arnaldo
From: Arnaldo Carvalho de Melo <acme@redhat.com>
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 <acme@redhat.com> --- 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
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