[PATCH v1 03/11] perf tools: Add nsinfo__new_thread() to track tid

[Namhyung Kim <namhyung@kernel.org>]

Record the thread ID (tid) in struct nsinfo via nsinfo__new_thread() and
access /proc/<pid>/task/<tid>/ status and ns/mnt paths instead of only
/proc/<pid>/.  Also recreate thread->nsinfo when the pid of the thread
is updated.

Assisted-by: LLM
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/util/machine.c    |  3 +++
 tools/perf/util/namespaces.c | 22 ++++++++++++++++++----
 tools/perf/util/namespaces.h |  3 +++
 tools/perf/util/thread.c     |  2 +-
 4 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 1d9d3bf57720008e..14f52234d4d99fb6 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -19,6 +19,7 @@
 #include "branch.h"
 #include "mem-events.h"
 #include "mem-info.h"
+#include "namespaces.h"
 #include "path.h"
 #include "srcline.h"
 #include "symbol.h"
@@ -495,6 +496,8 @@ static void machine__update_thread_pid(struct machine *machine,
 		return;
 
 	thread__set_pid(th, pid);
+	nsinfo__zput(RC_CHK_ACCESS(th)->nsinfo);
+	RC_CHK_ACCESS(th)->nsinfo = nsinfo__new_thread(pid, thread__tid(th));
 
 	if (thread__pid(th) == thread__tid(th))
 		return;
diff --git a/tools/perf/util/namespaces.c b/tools/perf/util/namespaces.c
index 01502570b32d02ab..f426eba04d6ef449 100644
--- a/tools/perf/util/namespaces.c
+++ b/tools/perf/util/namespaces.c
@@ -106,7 +106,8 @@ int nsinfo__init(struct nsinfo *nsi)
 	if (snprintf(oldns, PATH_MAX, "/proc/self/ns/mnt") >= PATH_MAX)
 		return rv;
 
-	if (asprintf(&newns, "/proc/%d/ns/mnt", nsinfo__pid(nsi)) == -1)
+	if (asprintf(&newns, "/proc/%d/task/%d/ns/mnt",
+		     nsinfo__pid(nsi), nsinfo__tid(nsi)) == -1)
 		return rv;
 
 	if (stat(oldns, &old_stat) < 0)
@@ -127,7 +128,8 @@ int nsinfo__init(struct nsinfo *nsi)
 	/* If we're dealing with a process that is in a different PID namespace,
 	 * attempt to work out the innermost tgid for the process.
 	 */
-	if (snprintf(spath, PATH_MAX, "/proc/%d/status", nsinfo__pid(nsi)) >= PATH_MAX)
+	if (snprintf(spath, PATH_MAX, "/proc/%d/task/%d/status",
+		     nsinfo__pid(nsi), nsinfo__tid(nsi)) >= PATH_MAX)
 		goto out;
 
 	rv = nsinfo__get_nspid(&RC_CHK_ACCESS(nsi)->tgid, &RC_CHK_ACCESS(nsi)->nstgid,
@@ -150,11 +152,11 @@ static struct nsinfo *nsinfo__alloc(void)
 	return res;
 }
 
-struct nsinfo *nsinfo__new(pid_t pid)
+struct nsinfo *nsinfo__new_thread(pid_t pid, pid_t tid)
 {
 	struct nsinfo *nsi;
 
-	if (pid == 0)
+	if (pid <= 0 || tid <= 0)
 		return NULL;
 
 	nsi = nsinfo__alloc();
@@ -162,6 +164,7 @@ struct nsinfo *nsinfo__new(pid_t pid)
 		return NULL;
 
 	RC_CHK_ACCESS(nsi)->pid = pid;
+	RC_CHK_ACCESS(nsi)->tid = tid;
 	RC_CHK_ACCESS(nsi)->tgid = pid;
 	RC_CHK_ACCESS(nsi)->nstgid = pid;
 	nsinfo__clear_need_setns(nsi);
@@ -176,6 +179,11 @@ struct nsinfo *nsinfo__new(pid_t pid)
 	return nsi;
 }
 
+struct nsinfo *nsinfo__new(pid_t pid)
+{
+	return nsinfo__new_thread(pid, pid);
+}
+
 static const char *nsinfo__mntns_path(const struct nsinfo *nsi)
 {
 	return RC_CHK_ACCESS(nsi)->mntns_path;
@@ -193,6 +201,7 @@ struct nsinfo *nsinfo__copy(const struct nsinfo *nsi)
 		return NULL;
 
 	RC_CHK_ACCESS(nnsi)->pid = nsinfo__pid(nsi);
+	RC_CHK_ACCESS(nnsi)->tid = nsinfo__tid(nsi);
 	RC_CHK_ACCESS(nnsi)->tgid = nsinfo__tgid(nsi);
 	RC_CHK_ACCESS(nnsi)->nstgid = nsinfo__nstgid(nsi);
 	RC_CHK_ACCESS(nnsi)->need_setns = nsinfo__need_setns(nsi);
@@ -265,6 +274,11 @@ pid_t nsinfo__pid(const struct nsinfo  *nsi)
 	return RC_CHK_ACCESS(nsi)->pid;
 }
 
+pid_t nsinfo__tid(const struct nsinfo  *nsi)
+{
+	return RC_CHK_ACCESS(nsi)->tid;
+}
+
 bool nsinfo__in_pidns(const struct nsinfo *nsi)
 {
 	return RC_CHK_ACCESS(nsi)->in_pidns;
diff --git a/tools/perf/util/namespaces.h b/tools/perf/util/namespaces.h
index e95c79b80e27c8fc..ea645954944de4be 100644
--- a/tools/perf/util/namespaces.h
+++ b/tools/perf/util/namespaces.h
@@ -32,6 +32,7 @@ void namespaces__free(struct namespaces *namespaces);
 
 DECLARE_RC_STRUCT(nsinfo) {
 	pid_t			pid;
+	pid_t			tid;
 	pid_t			tgid;
 	pid_t			nstgid;
 	bool			need_setns;
@@ -48,6 +49,7 @@ struct nscookie {
 
 int nsinfo__init(struct nsinfo *nsi);
 struct nsinfo *nsinfo__new(pid_t pid);
+struct nsinfo *nsinfo__new_thread(pid_t pid, pid_t tid);
 struct nsinfo *nsinfo__copy(const struct nsinfo *nsi);
 
 struct nsinfo *nsinfo__get(struct nsinfo *nsi);
@@ -58,6 +60,7 @@ void nsinfo__clear_need_setns(struct nsinfo *nsi);
 pid_t nsinfo__tgid(const struct nsinfo  *nsi);
 pid_t nsinfo__nstgid(const struct nsinfo  *nsi);
 pid_t nsinfo__pid(const struct nsinfo  *nsi);
+pid_t nsinfo__tid(const struct nsinfo  *nsi);
 bool nsinfo__in_pidns(const struct nsinfo  *nsi);
 void nsinfo__set_in_pidns(struct nsinfo *nsi);
 
diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index 91118c301913b834..d12eb6bc63313b00 100644
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -71,7 +71,7 @@ struct thread *thread__new(pid_t pid, pid_t tid)
 		list_add(&comm->list, thread__comm_list(thread));
 		refcount_set(thread__refcnt(thread), 1);
 		/* Thread holds first ref to nsdata. */
-		RC_CHK_ACCESS(thread)->nsinfo = nsinfo__new(pid);
+		RC_CHK_ACCESS(thread)->nsinfo = nsinfo__new_thread(pid, tid);
 		srccode_state_init(thread__srccode_state(thread));
 	}
 
-- 
2.56.0.257.gf7497c7d27-goog