Em Fri, Sep 29, 2017 at 07:47:52AM -0700, [email protected] escreveu: > From: Kan Liang <[email protected]> > > Add two locks to protect namespaces_list and comm_list. > > The lock is only needed for multithreaded code, so using mutex wrappers > provided by perf tool. > > Not all the comm_list/namespaces_list accessing are protected, e.g. > thread__exec_comm. Because the multithread code for perf top event > synthesizing does not touch them. They don't need a lock.
They don't need a lock _now_, ok I think we can proceed that way, this cset should serve as a warning to people working in further multithreading perf. - Arnaldo > Signed-off-by: Kan Liang <[email protected]> > --- > tools/perf/util/thread.c | 53 > +++++++++++++++++++++++++++++++++++++++++++----- > tools/perf/util/thread.h | 3 +++ > 2 files changed, 51 insertions(+), 5 deletions(-) > > diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c > index c09bdb5..bf73117 100644 > --- a/tools/perf/util/thread.c > +++ b/tools/perf/util/thread.c > @@ -45,6 +45,8 @@ struct thread *thread__new(pid_t pid, pid_t tid) > thread->cpu = -1; > INIT_LIST_HEAD(&thread->namespaces_list); > INIT_LIST_HEAD(&thread->comm_list); > + init_rwsem(&thread->namespaces_lock); > + init_rwsem(&thread->comm_lock); > > comm_str = malloc(32); > if (!comm_str) > @@ -83,18 +85,26 @@ void thread__delete(struct thread *thread) > map_groups__put(thread->mg); > thread->mg = NULL; > } > + down_write(&thread->namespaces_lock); > list_for_each_entry_safe(namespaces, tmp_namespaces, > &thread->namespaces_list, list) { > list_del(&namespaces->list); > namespaces__free(namespaces); > } > + up_write(&thread->namespaces_lock); > + > + down_write(&thread->comm_lock); > list_for_each_entry_safe(comm, tmp_comm, &thread->comm_list, list) { > list_del(&comm->list); > comm__free(comm); > } > + up_write(&thread->comm_lock); > + > unwind__finish_access(thread); > nsinfo__zput(thread->nsinfo); > > + exit_rwsem(&thread->namespaces_lock); > + exit_rwsem(&thread->comm_lock); > free(thread); > } > > @@ -125,8 +135,8 @@ struct namespaces *thread__namespaces(const struct thread > *thread) > return list_first_entry(&thread->namespaces_list, struct namespaces, > list); > } > > -int thread__set_namespaces(struct thread *thread, u64 timestamp, > - struct namespaces_event *event) > +static int __thread__set_namespaces(struct thread *thread, u64 timestamp, > + struct namespaces_event *event) > { > struct namespaces *new, *curr = thread__namespaces(thread); > > @@ -149,6 +159,17 @@ int thread__set_namespaces(struct thread *thread, u64 > timestamp, > return 0; > } > > +int thread__set_namespaces(struct thread *thread, u64 timestamp, > + struct namespaces_event *event) > +{ > + int ret; > + > + down_write(&thread->namespaces_lock); > + ret = __thread__set_namespaces(thread, timestamp, event); > + up_write(&thread->namespaces_lock); > + return ret; > +} > + > struct comm *thread__comm(const struct thread *thread) > { > if (list_empty(&thread->comm_list)) > @@ -170,8 +191,8 @@ struct comm *thread__exec_comm(const struct thread > *thread) > return last; > } > > -int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp, > - bool exec) > +static int ____thread__set_comm(struct thread *thread, const char *str, > + u64 timestamp, bool exec) > { > struct comm *new, *curr = thread__comm(thread); > > @@ -195,6 +216,17 @@ int __thread__set_comm(struct thread *thread, const char > *str, u64 timestamp, > return 0; > } > > +int __thread__set_comm(struct thread *thread, const char *str, u64 timestamp, > + bool exec) > +{ > + int ret; > + > + down_write(&thread->comm_lock); > + ret = ____thread__set_comm(thread, str, timestamp, exec); > + up_write(&thread->comm_lock); > + return ret; > +} > + > int thread__set_comm_from_proc(struct thread *thread) > { > char path[64]; > @@ -212,7 +244,7 @@ int thread__set_comm_from_proc(struct thread *thread) > return err; > } > > -const char *thread__comm_str(const struct thread *thread) > +static const char *__thread__comm_str(const struct thread *thread) > { > const struct comm *comm = thread__comm(thread); > > @@ -222,6 +254,17 @@ const char *thread__comm_str(const struct thread *thread) > return comm__str(comm); > } > > +const char *thread__comm_str(const struct thread *thread) > +{ > + const char *str; > + > + down_read((struct rw_semaphore *)&thread->comm_lock); > + str = __thread__comm_str(thread); > + up_read((struct rw_semaphore *)&thread->comm_lock); > + > + return str; > +} > + > /* CHECKME: it should probably better return the max comm len from its comm > list */ > int thread__comm_len(struct thread *thread) > { > diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h > index cb1a5dd..10555d6 100644 > --- a/tools/perf/util/thread.h > +++ b/tools/perf/util/thread.h > @@ -9,6 +9,7 @@ > #include "symbol.h" > #include <strlist.h> > #include <intlist.h> > +#include "rwsem.h" > > struct thread_stack; > struct unwind_libunwind_ops; > @@ -29,7 +30,9 @@ struct thread { > int comm_len; > bool dead; /* if set thread has exited */ > struct list_head namespaces_list; > + struct rw_semaphore namespaces_lock; > struct list_head comm_list; > + struct rw_semaphore comm_lock; > u64 db_id; > > void *priv; > -- > 2.5.5
