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Revert "perf thread: Ensure comm_lock held for comm_list"

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This reverts commit 8f454c9581.

'perf top' is freezing on exit sometimes, bisected to this one, revert.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Bill Wendling <morbo@google.com>
Cc: Chaitanya S Prakash <chaitanyas.prakash@arm.com>
Cc: Fei Lang <langfei@huawei.com>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Justin Stitt <justinstitt@google.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Nick Desaulniers <nick.desaulniers+lkml@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Link: https://lore.kernel.org/r/aDcyvvOKZkRYbjul@x1
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo 2025-05-28 12:53:08 -03:00
parent 6dd7a0fde9
commit 24bcc31fc7
3 changed files with 9 additions and 21 deletions
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2
tools/perf/util/comm.c
View File

@ -24,7 +24,6 @@ static struct comm_strs {
static void comm_strs__remove_if_last(struct comm_str *cs);
static void comm_strs__init(void)
NO_THREAD_SAFETY_ANALYSIS /* Inherently single threaded due to pthread_once. */
{
init_rwsem(&_comm_strs.lock);
_comm_strs.capacity = 16;
@ -120,7 +119,6 @@ static void comm_strs__remove_if_last(struct comm_str *cs)
}
static struct comm_str *__comm_strs__find(struct comm_strs *comm_strs, const char *str)
SHARED_LOCKS_REQUIRED(comm_strs->lock)
{
struct comm_str **result;

17
tools/perf/util/thread.c
View File

@ -41,7 +41,6 @@ int thread__init_maps(struct thread *thread, struct machine *machine)
}
struct thread *thread__new(pid_t pid, pid_t tid)
NO_THREAD_SAFETY_ANALYSIS /* Allocation/creation is inherently single threaded. */
{
RC_STRUCT(thread) *_thread = zalloc(sizeof(*_thread));
struct thread *thread;
@ -203,29 +202,22 @@ int thread__set_namespaces(struct thread *thread, u64 timestamp,
struct comm *thread__comm(struct thread *thread)
{
struct comm *res = NULL;
if (list_empty(thread__comm_list(thread)))
return NULL;
down_read(thread__comm_lock(thread));
if (!list_empty(thread__comm_list(thread)))
res = list_first_entry(thread__comm_list(thread), struct comm, list);
up_read(thread__comm_lock(thread));
return res;
return list_first_entry(thread__comm_list(thread), struct comm, list);
}
struct comm *thread__exec_comm(struct thread *thread)
{
struct comm *comm, *last = NULL, *second_last = NULL;
down_read(thread__comm_lock(thread));
list_for_each_entry(comm, thread__comm_list(thread), list) {
if (comm->exec) {
up_read(thread__comm_lock(thread));
if (comm->exec)
return comm;
}
second_last = last;
last = comm;
}
up_read(thread__comm_lock(thread));
/*
* 'last' with no start time might be the parent's comm of a synthesized
@ -241,7 +233,6 @@ struct comm *thread__exec_comm(struct thread *thread)
static int ____thread__set_comm(struct thread *thread, const char *str,
u64 timestamp, bool exec)
EXCLUSIVE_LOCKS_REQUIRED(thread__comm_lock(thread))
{
struct comm *new, *curr = thread__comm(thread);

11
tools/perf/util/thread.h
View File

@ -236,17 +236,16 @@ static inline struct rw_semaphore *thread__namespaces_lock(struct thread *thread
return &RC_CHK_ACCESS(thread)->namespaces_lock;
}
static inline struct list_head *thread__comm_list(struct thread *thread)
{
return &RC_CHK_ACCESS(thread)->comm_list;
}
static inline struct rw_semaphore *thread__comm_lock(struct thread *thread)
{
return &RC_CHK_ACCESS(thread)->comm_lock;
}
static inline struct list_head *thread__comm_list(struct thread *thread)
SHARED_LOCKS_REQUIRED(thread__comm_lock(thread))
{
return &RC_CHK_ACCESS(thread)->comm_list;
}
static inline u64 thread__db_id(const struct thread *thread)
{
return RC_CHK_ACCESS(thread)->db_id;