Em Tue, Oct 30, 2018 at 10:24:04PM -0700, David Miller escreveu: > > When synthesizing FORK events, we are trying to create thread objects > for the already running tasks on the machine. > > Normally, for a kernel FORK event, we want to clone the parent's maps > because that is what the kernel just did. > > But when synthesizing, this should not be done. If we do, we end up > with overlapping maps as we process the sythesized MMAP2 events that > get delivered shortly thereafter. > > Use the FORK event misc flags in an internal way to signal this > situation, so we can elide the map clone when appropriate.
Thanks, applied. - Arnaldo > Signed-off-by: David S. Miller <[email protected]> > > diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h > index f35eb72739c0..9de8780ac8d9 100644 > --- a/include/uapi/linux/perf_event.h > +++ b/include/uapi/linux/perf_event.h > @@ -646,10 +646,12 @@ struct perf_event_mmap_page { > * > * PERF_RECORD_MISC_MMAP_DATA - PERF_RECORD_MMAP* events > * PERF_RECORD_MISC_COMM_EXEC - PERF_RECORD_COMM event > + * PERF_RECORD_MISC_FORK_EXEC - PERF_RECORD_FORK event (perf internal) > * PERF_RECORD_MISC_SWITCH_OUT - PERF_RECORD_SWITCH* events > */ > #define PERF_RECORD_MISC_MMAP_DATA (1 << 13) > #define PERF_RECORD_MISC_COMM_EXEC (1 << 13) > +#define PERF_RECORD_MISC_FORK_EXEC (1 << 13) > #define PERF_RECORD_MISC_SWITCH_OUT (1 << 13) > /* > * These PERF_RECORD_MISC_* flags below are safely reused > diff --git a/tools/include/uapi/linux/perf_event.h > b/tools/include/uapi/linux/perf_event.h > index f35eb72739c0..9de8780ac8d9 100644 > --- a/tools/include/uapi/linux/perf_event.h > +++ b/tools/include/uapi/linux/perf_event.h > @@ -646,10 +646,12 @@ struct perf_event_mmap_page { > * > * PERF_RECORD_MISC_MMAP_DATA - PERF_RECORD_MMAP* events > * PERF_RECORD_MISC_COMM_EXEC - PERF_RECORD_COMM event > + * PERF_RECORD_MISC_FORK_EXEC - PERF_RECORD_FORK event (perf internal) > * PERF_RECORD_MISC_SWITCH_OUT - PERF_RECORD_SWITCH* events > */ > #define PERF_RECORD_MISC_MMAP_DATA (1 << 13) > #define PERF_RECORD_MISC_COMM_EXEC (1 << 13) > +#define PERF_RECORD_MISC_FORK_EXEC (1 << 13) > #define PERF_RECORD_MISC_SWITCH_OUT (1 << 13) > /* > * These PERF_RECORD_MISC_* flags below are safely reused > diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c > index bc646185f8d9..e9c108a6b1c3 100644 > --- a/tools/perf/util/event.c > +++ b/tools/perf/util/event.c > @@ -308,6 +308,7 @@ static int perf_event__synthesize_fork(struct perf_tool > *tool, > event->fork.pid = tgid; > event->fork.tid = pid; > event->fork.header.type = PERF_RECORD_FORK; > + event->fork.header.misc = PERF_RECORD_MISC_FORK_EXEC; > > event->fork.header.size = (sizeof(event->fork) + machine->id_hdr_size); > > diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c > index 111ae858cbcb..214b7979c4e7 100644 > --- a/tools/perf/util/machine.c > +++ b/tools/perf/util/machine.c > @@ -1708,6 +1708,7 @@ int machine__process_fork_event(struct machine > *machine, union perf_event *event > struct thread *parent = machine__findnew_thread(machine, > event->fork.ppid, > event->fork.ptid); > + bool do_maps_clone = true; > int err = 0; > > if (dump_trace) > @@ -1737,8 +1738,11 @@ int machine__process_fork_event(struct machine > *machine, union perf_event *event > thread = machine__findnew_thread(machine, event->fork.pid, > event->fork.tid); > > + if (event->fork.header.misc & PERF_RECORD_MISC_FORK_EXEC) > + do_maps_clone = false; > + > if (thread == NULL || parent == NULL || > - thread__fork(thread, parent, sample->time) < 0) { > + thread__fork(thread, parent, sample->time, do_maps_clone) < 0) { > dump_printf("problem processing PERF_RECORD_FORK, skipping > event.\n"); > err = -1; > } > diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c > index 2048d393ece6..54b2c9ceba9f 100644 > --- a/tools/perf/util/thread.c > +++ b/tools/perf/util/thread.c > @@ -330,7 +330,8 @@ static int thread__prepare_access(struct thread *thread) > } > > static int thread__clone_map_groups(struct thread *thread, > - struct thread *parent) > + struct thread *parent, > + bool do_maps_clone) > { > /* This is new thread, we share map groups for process. */ > if (thread->pid_ == parent->pid_) > @@ -341,15 +342,14 @@ static int thread__clone_map_groups(struct thread > *thread, > thread->pid_, thread->tid, parent->pid_, parent->tid); > return 0; > } > - > /* But this one is new process, copy maps. */ > - if (map_groups__clone(thread, parent->mg) < 0) > + if (do_maps_clone && > + map_groups__clone(thread, parent->mg) < 0) > return -ENOMEM; > - > return 0; > } > > -int thread__fork(struct thread *thread, struct thread *parent, u64 timestamp) > +int thread__fork(struct thread *thread, struct thread *parent, u64 > timestamp, bool do_maps_clone) > { > if (parent->comm_set) { > const char *comm = thread__comm_str(parent); > @@ -362,7 +362,7 @@ int thread__fork(struct thread *thread, struct thread > *parent, u64 timestamp) > } > > thread->ppid = parent->tid; > - return thread__clone_map_groups(thread, parent); > + return thread__clone_map_groups(thread, parent, do_maps_clone); > } > > void thread__find_cpumode_addr_location(struct thread *thread, u64 addr, > diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h > index 07606aa6998d..7e30fe99b74b 100644 > --- a/tools/perf/util/thread.h > +++ b/tools/perf/util/thread.h > @@ -87,7 +87,7 @@ struct comm *thread__comm(const struct thread *thread); > struct comm *thread__exec_comm(const struct thread *thread); > const char *thread__comm_str(const struct thread *thread); > int thread__insert_map(struct thread *thread, struct map *map); > -int thread__fork(struct thread *thread, struct thread *parent, u64 > timestamp); > +int thread__fork(struct thread *thread, struct thread *parent, u64 > timestamp, bool do_maps_clone); > size_t thread__fprintf(struct thread *thread, FILE *fp); > > struct thread *thread__main_thread(struct machine *machine, struct thread > *thread);
