[PATCH v2 24/26] perf callchain: Use pthread keys for tls callchain_cursor
From: Ian Rogers
Date: Thu Jun 08 2023 - 19:31:47 EST
Pthread keys are more portable than __thread and allow the association
of a destructor with the key. Use the destructor to clean up TLS
callchain cursors to aid understanding memory leaks.
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
tools/perf/builtin-c2c.c | 4 +-
tools/perf/builtin-script.c | 24 ++++++-----
tools/perf/util/callchain.c | 40 ++++++++++++++++++-
tools/perf/util/callchain.h | 4 +-
tools/perf/util/db-export.c | 10 +++--
tools/perf/util/hist.c | 29 ++++++++------
.../scripting-engines/trace-event-python.c | 10 +++--
7 files changed, 86 insertions(+), 35 deletions(-)
diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
index 530a44a59f41..a4cf9de7a7b5 100644
--- a/tools/perf/builtin-c2c.c
+++ b/tools/perf/builtin-c2c.c
@@ -284,6 +284,7 @@ static int process_sample_event(struct perf_tool *tool __maybe_unused,
struct hist_entry *he;
struct addr_location al;
struct mem_info *mi, *mi_dup;
+ struct callchain_cursor *cursor;
int ret;
addr_location__init(&al);
@@ -297,7 +298,8 @@ static int process_sample_event(struct perf_tool *tool __maybe_unused,
if (c2c.stitch_lbr)
thread__set_lbr_stitch_enable(al.thread, true);
- ret = sample__resolve_callchain(sample, &callchain_cursor, NULL,
+ cursor = get_tls_callchain_cursor();
+ ret = sample__resolve_callchain(sample, cursor, NULL,
evsel, &al, sysctl_perf_event_max_stack);
if (ret)
goto out;
diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 784d478c2e05..e3f435e6a7d0 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -1557,11 +1557,13 @@ static int perf_sample__fprintf_bts(struct perf_sample *sample,
unsigned int print_opts = output[type].print_ip_opts;
struct callchain_cursor *cursor = NULL;
- if (symbol_conf.use_callchain && sample->callchain &&
- thread__resolve_callchain(al->thread, &callchain_cursor, evsel,
- sample, NULL, NULL, scripting_max_stack) == 0)
- cursor = &callchain_cursor;
-
+ if (symbol_conf.use_callchain && sample->callchain) {
+ cursor = get_tls_callchain_cursor();
+ if (thread__resolve_callchain(al->thread, cursor, evsel,
+ sample, NULL, NULL,
+ scripting_max_stack))
+ cursor = NULL;
+ }
if (cursor == NULL) {
printed += fprintf(fp, " ");
if (print_opts & EVSEL__PRINT_SRCLINE) {
@@ -2203,11 +2205,13 @@ static void process_event(struct perf_script *script,
if (script->stitch_lbr)
thread__set_lbr_stitch_enable(al->thread, true);
- if (symbol_conf.use_callchain && sample->callchain &&
- thread__resolve_callchain(al->thread, &callchain_cursor, evsel,
- sample, NULL, NULL, scripting_max_stack) == 0)
- cursor = &callchain_cursor;
-
+ if (symbol_conf.use_callchain && sample->callchain) {
+ cursor = get_tls_callchain_cursor();
+ if (thread__resolve_callchain(al->thread, cursor, evsel,
+ sample, NULL, NULL,
+ scripting_max_stack))
+ cursor = NULL;
+ }
fputc(cursor ? '\n' : ' ', fp);
sample__fprintf_sym(sample, al, 0, output[type].print_ip_opts, cursor,
symbol_conf.bt_stop_list, fp);
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 909f62b3b266..7e9bd3b6be9f 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -58,7 +58,8 @@ struct callchain_param callchain_param_default = {
CALLCHAIN_PARAM_DEFAULT
};
-__thread struct callchain_cursor callchain_cursor;
+/* Used for thread-local struct callchain_cursor. */
+static pthread_key_t callchain_cursor;
int parse_callchain_record_opt(const char *arg, struct callchain_param *param)
{
@@ -1116,7 +1117,7 @@ int hist_entry__append_callchain(struct hist_entry *he, struct perf_sample *samp
if ((!symbol_conf.use_callchain || sample->callchain == NULL) &&
!symbol_conf.show_branchflag_count)
return 0;
- return callchain_append(he->callchain, &callchain_cursor, sample->period);
+ return callchain_append(he->callchain, get_tls_callchain_cursor(), sample->period);
}
int fill_callchain_info(struct addr_location *al, struct callchain_cursor_node *node,
@@ -1570,6 +1571,41 @@ int callchain_node__make_parent_list(struct callchain_node *node)
return -ENOMEM;
}
+static void callchain_cursor__delete(void *vcursor)
+{
+ struct callchain_cursor *cursor = vcursor;
+ struct callchain_cursor_node *node, *next;
+
+ callchain_cursor_reset(cursor);
+ for (node = cursor->first; node != NULL; node = next) {
+ next = node->next;
+ free(node);
+ }
+ free(cursor);
+}
+
+static void init_callchain_cursor_key(void)
+{
+ if (pthread_key_create(&callchain_cursor, callchain_cursor__delete)) {
+ pr_err("callchain cursor creation failed");
+ abort();
+ }
+}
+
+struct callchain_cursor *get_tls_callchain_cursor(void)
+{
+ static pthread_once_t once_control = PTHREAD_ONCE_INIT;
+ struct callchain_cursor *cursor;
+
+ pthread_once(&once_control, init_callchain_cursor_key);
+ cursor = pthread_getspecific(callchain_cursor);
+ if (!cursor) {
+ cursor = zalloc(sizeof(*cursor));
+ pthread_setspecific(callchain_cursor, cursor);
+ }
+ return cursor;
+}
+
int callchain_cursor__copy(struct callchain_cursor *dst,
struct callchain_cursor *src)
{
diff --git a/tools/perf/util/callchain.h b/tools/perf/util/callchain.h
index d95615daed73..ce9410018cf7 100644
--- a/tools/perf/util/callchain.h
+++ b/tools/perf/util/callchain.h
@@ -168,8 +168,6 @@ struct callchain_cursor {
struct callchain_cursor_node *curr;
};
-extern __thread struct callchain_cursor callchain_cursor;
-
static inline void callchain_init(struct callchain_root *root)
{
INIT_LIST_HEAD(&root->node.val);
@@ -231,6 +229,8 @@ static inline void callchain_cursor_advance(struct callchain_cursor *cursor)
cursor->pos++;
}
+struct callchain_cursor *get_tls_callchain_cursor(void);
+
int callchain_cursor__copy(struct callchain_cursor *dst,
struct callchain_cursor *src);
diff --git a/tools/perf/util/db-export.c b/tools/perf/util/db-export.c
index 6184696dc266..b9fb71ab7a73 100644
--- a/tools/perf/util/db-export.c
+++ b/tools/perf/util/db-export.c
@@ -215,6 +215,7 @@ static struct call_path *call_path_from_sample(struct db_export *dbe,
u64 kernel_start = machine__kernel_start(machine);
struct call_path *current = &dbe->cpr->call_path;
enum chain_order saved_order = callchain_param.order;
+ struct callchain_cursor *cursor;
int err;
if (!symbol_conf.use_callchain || !sample->callchain)
@@ -226,13 +227,14 @@ static struct call_path *call_path_from_sample(struct db_export *dbe,
* the callchain starting with the root node and ending with the leaf.
*/
callchain_param.order = ORDER_CALLER;
- err = thread__resolve_callchain(thread, &callchain_cursor, evsel,
+ cursor = get_tls_callchain_cursor();
+ err = thread__resolve_callchain(thread, cursor, evsel,
sample, NULL, NULL, PERF_MAX_STACK_DEPTH);
if (err) {
callchain_param.order = saved_order;
return NULL;
}
- callchain_cursor_commit(&callchain_cursor);
+ callchain_cursor_commit(cursor);
while (1) {
struct callchain_cursor_node *node;
@@ -240,7 +242,7 @@ static struct call_path *call_path_from_sample(struct db_export *dbe,
u64 dso_db_id = 0, sym_db_id = 0, offset = 0;
- node = callchain_cursor_current(&callchain_cursor);
+ node = callchain_cursor_current(cursor);
if (!node)
break;
@@ -265,7 +267,7 @@ static struct call_path *call_path_from_sample(struct db_export *dbe,
al.sym, node->ip,
kernel_start);
- callchain_cursor_advance(&callchain_cursor);
+ callchain_cursor_advance(cursor);
addr_location__exit(&al);
}
diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index fb218b3e8a7c..4004c0915e4f 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -1029,15 +1029,16 @@ iter_prepare_cumulative_entry(struct hist_entry_iter *iter,
struct addr_location *al __maybe_unused)
{
struct hist_entry **he_cache;
+ struct callchain_cursor *cursor = get_tls_callchain_cursor();
- callchain_cursor_commit(&callchain_cursor);
+ callchain_cursor_commit(cursor);
/*
* This is for detecting cycles or recursions so that they're
* cumulated only one time to prevent entries more than 100%
* overhead.
*/
- he_cache = malloc(sizeof(*he_cache) * (callchain_cursor.nr + 1));
+ he_cache = malloc(sizeof(*he_cache) * (cursor->nr + 1));
if (he_cache == NULL)
return -ENOMEM;
@@ -1072,7 +1073,7 @@ iter_add_single_cumulative_entry(struct hist_entry_iter *iter,
* We need to re-initialize the cursor since callchain_append()
* advanced the cursor to the end.
*/
- callchain_cursor_commit(&callchain_cursor);
+ callchain_cursor_commit(get_tls_callchain_cursor());
hists__inc_nr_samples(hists, he->filtered);
@@ -1085,7 +1086,7 @@ iter_next_cumulative_entry(struct hist_entry_iter *iter,
{
struct callchain_cursor_node *node;
- node = callchain_cursor_current(&callchain_cursor);
+ node = callchain_cursor_current(get_tls_callchain_cursor());
if (node == NULL)
return 0;
@@ -1131,12 +1132,12 @@ iter_add_next_cumulative_entry(struct hist_entry_iter *iter,
.raw_size = sample->raw_size,
};
int i;
- struct callchain_cursor cursor;
+ struct callchain_cursor cursor, *tls_cursor = get_tls_callchain_cursor();
bool fast = hists__has(he_tmp.hists, sym);
- callchain_cursor_snapshot(&cursor, &callchain_cursor);
+ callchain_cursor_snapshot(&cursor, tls_cursor);
- callchain_cursor_advance(&callchain_cursor);
+ callchain_cursor_advance(tls_cursor);
/*
* Check if there's duplicate entries in the callchain.
@@ -1222,7 +1223,7 @@ int hist_entry_iter__add(struct hist_entry_iter *iter, struct addr_location *al,
if (al)
alm = map__get(al->map);
- err = sample__resolve_callchain(iter->sample, &callchain_cursor, &iter->parent,
+ err = sample__resolve_callchain(iter->sample, get_tls_callchain_cursor(), &iter->parent,
iter->evsel, al, max_stack_depth);
if (err) {
map__put(alm);
@@ -1568,8 +1569,10 @@ static int hists__hierarchy_insert_entry(struct hists *hists,
if (hist_entry__has_callchains(new_he) &&
symbol_conf.use_callchain) {
- callchain_cursor_reset(&callchain_cursor);
- if (callchain_merge(&callchain_cursor,
+ struct callchain_cursor *cursor = get_tls_callchain_cursor();
+
+ callchain_cursor_reset(cursor);
+ if (callchain_merge(cursor,
new_he->callchain,
he->callchain) < 0)
ret = -1;
@@ -1610,8 +1613,10 @@ static int hists__collapse_insert_entry(struct hists *hists,
he_stat__add_stat(iter->stat_acc, he->stat_acc);
if (hist_entry__has_callchains(he) && symbol_conf.use_callchain) {
- callchain_cursor_reset(&callchain_cursor);
- if (callchain_merge(&callchain_cursor,
+ struct callchain_cursor *cursor = get_tls_callchain_cursor();
+
+ callchain_cursor_reset(cursor);
+ if (callchain_merge(cursor,
iter->callchain,
he->callchain) < 0)
ret = -1;
diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
index d96e5c0fef45..59063ec98619 100644
--- a/tools/perf/util/scripting-engines/trace-event-python.c
+++ b/tools/perf/util/scripting-engines/trace-event-python.c
@@ -417,6 +417,7 @@ static PyObject *python_process_callchain(struct perf_sample *sample,
struct addr_location *al)
{
PyObject *pylist;
+ struct callchain_cursor *cursor;
pylist = PyList_New(0);
if (!pylist)
@@ -425,19 +426,20 @@ static PyObject *python_process_callchain(struct perf_sample *sample,
if (!symbol_conf.use_callchain || !sample->callchain)
goto exit;
- if (thread__resolve_callchain(al->thread, &callchain_cursor, evsel,
+ cursor = get_tls_callchain_cursor();
+ if (thread__resolve_callchain(al->thread, cursor, evsel,
sample, NULL, NULL,
scripting_max_stack) != 0) {
pr_err("Failed to resolve callchain. Skipping\n");
goto exit;
}
- callchain_cursor_commit(&callchain_cursor);
+ callchain_cursor_commit(cursor);
while (1) {
PyObject *pyelem;
struct callchain_cursor_node *node;
- node = callchain_cursor_current(&callchain_cursor);
+ node = callchain_cursor_current(cursor);
if (!node)
break;
@@ -493,7 +495,7 @@ static PyObject *python_process_callchain(struct perf_sample *sample,
_PyUnicode_FromString(dsoname));
}
- callchain_cursor_advance(&callchain_cursor);
+ callchain_cursor_advance(cursor);
PyList_Append(pylist, pyelem);
Py_DECREF(pyelem);
}
--
2.41.0.162.gfafddb0af9-goog