diff --git a/tools/perf/util/comm.c b/tools/perf/util/comm.c index 1aa9a08e5b03..233f2b6edf52 100644 --- a/tools/perf/util/comm.c +++ b/tools/perf/util/comm.c @@ -19,6 +19,8 @@ static struct comm_strs { int capacity; } _comm_strs; +static void comm_strs__remove_if_last(struct comm_str *cs); + static void comm_strs__init(void) { init_rwsem(&_comm_strs.lock); @@ -58,22 +60,15 @@ static struct comm_str *comm_str__get(struct comm_str *cs) static void comm_str__put(struct comm_str *cs) { - if (cs && refcount_dec_and_test(comm_str__refcnt(cs))) { - struct comm_strs *comm_strs = comm_strs__get(); - int i; + if (!cs) + return; - down_write(&comm_strs->lock); - for (i = 0; i < comm_strs->num_strs; i++) { - if (comm_strs->strs[i] == cs) - break; - } - for (; i < comm_strs->num_strs - 1; i++) - comm_strs->strs[i] = comm_strs->strs[i + 1]; - - comm_strs->num_strs--; - up_write(&comm_strs->lock); + if (refcount_dec_and_test(comm_str__refcnt(cs))) { RC_CHK_FREE(cs); } else { + if (refcount_read(comm_str__refcnt(cs)) == 1) + comm_strs__remove_if_last(cs); + RC_CHK_PUT(cs); } } @@ -107,6 +102,28 @@ static int comm_str__search(const void *_key, const void *_member) return strcmp(key, comm_str__str(member)); } +static void comm_strs__remove_if_last(struct comm_str *cs) +{ + struct comm_strs *comm_strs = comm_strs__get(); + + down_write(&comm_strs->lock); + /* + * Are there only references from the array, if so remove the array + * reference under the write lock so that we don't race with findnew. + */ + if (refcount_read(comm_str__refcnt(cs)) == 1) { + struct comm_str **entry; + + entry = bsearch(comm_str__str(cs), comm_strs->strs, comm_strs->num_strs, + sizeof(struct comm_str *), comm_str__search); + comm_str__put(*entry); + for (int i = entry - comm_strs->strs; i < comm_strs->num_strs - 1; i++) + comm_strs->strs[i] = comm_strs->strs[i + 1]; + comm_strs->num_strs--; + } + up_write(&comm_strs->lock); +} + static struct comm_str *__comm_strs__find(struct comm_strs *comm_strs, const char *str) { struct comm_str **result; @@ -158,7 +175,7 @@ static struct comm_str *comm_strs__findnew(const char *str) } } up_write(&comm_strs->lock); - return result; + return comm_str__get(result); } struct comm *comm__new(const char *str, u64 timestamp, bool exec)