perf thread: Make threads rbtree non-invasive

Separate the rbtree out of thread and into a new struct
thread_rb_node. The refcnt is in thread and the rbtree is responsible
for a single count.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ali Saidi <alisaidi@amazon.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Brian Robbins <brianrob@linux.microsoft.com>
Cc: Changbin Du <changbin.du@huawei.com>
Cc: Dmitrii Dolgov <9erthalion6@gmail.com>
Cc: Fangrui Song <maskray@google.com>
Cc: German Gomez <german.gomez@arm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ivan Babrou <ivan@cloudflare.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jing Zhang <renyu.zj@linux.alibaba.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: K Prateek Nayak <kprateek.nayak@amd.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Miguel Ojeda <ojeda@kernel.org>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Steinar H. Gunderson <sesse@google.com>
Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
Cc: Wenyu Liu <liuwenyu7@huawei.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yang Jihong <yangjihong1@huawei.com>
Cc: Ye Xingchen <ye.xingchen@zte.com.cn>
Cc: Yuan Can <yuancan@huawei.com>
Cc: coresight@lists.linaro.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230608232823.4027869-3-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 92c6797..c7d5262 100644 (file)
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -911,7 +911,7 @@ static int tasks_print(struct report *rep, FILE *fp)
                     nd = rb_next(nd)) {
                        task = tasks + itask++;
 
-                       task->thread = rb_entry(nd, struct thread, rb_node);
+                       task->thread = rb_entry(nd, struct thread_rb_node, rb_node)->thread;
                        INIT_LIST_HEAD(&task->children);
                        INIT_LIST_HEAD(&task->list);
                        thread__set_priv(task->thread, task);

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 62c7c99..b0dd202 100644 (file)
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -4348,7 +4348,7 @@ DEFINE_RESORT_RB(threads, (thread__nr_events(a->thread->priv) < thread__nr_event
        struct thread *thread;
 )
 {
-       entry->thread = rb_entry(nd, struct thread, rb_node);
+       entry->thread = rb_entry(nd, struct thread_rb_node, rb_node)->thread;
 }
 
 static size_t trace__fprintf_thread_summary(struct trace *trace, FILE *fp)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index a1954ac..cbf092e 100644 (file)
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -43,7 +43,8 @@
 #include <linux/string.h>
 #include <linux/zalloc.h>
 
-static void __machine__remove_thread(struct machine *machine, struct thread *th, bool lock);
+static void __machine__remove_thread(struct machine *machine, struct thread_rb_node *nd,
+                                    struct thread *th, bool lock);
 static int append_inlines(struct callchain_cursor *cursor, struct map_symbol *ms, u64 ip);
 
 static struct dso *machine__kernel_dso(struct machine *machine)
@@ -72,6 +73,21 @@ static void machine__threads_init(struct machine *machine)
        }
 }
 
+static int thread_rb_node__cmp_tid(const void *key, const struct rb_node *nd)
+{
+       int to_find = (int) *((pid_t *)key);
+
+       return to_find - (int)rb_entry(nd, struct thread_rb_node, rb_node)->thread->tid;
+}
+
+static struct thread_rb_node *thread_rb_node__find(const struct thread *th,
+                                                  struct rb_root *tree)
+{
+       struct rb_node *nd = rb_find(&th->tid, tree, thread_rb_node__cmp_tid);
+
+       return rb_entry(nd, struct thread_rb_node, rb_node);
+}
+
 static int machine__set_mmap_name(struct machine *machine)
 {
        if (machine__is_host(machine))
@@ -214,10 +230,10 @@ void machine__delete_threads(struct machine *machine)
                down_write(&threads->lock);
                nd = rb_first_cached(&threads->entries);
                while (nd) {
-                       struct thread *t = rb_entry(nd, struct thread, rb_node);
+                       struct thread_rb_node *trb = rb_entry(nd, struct thread_rb_node, rb_node);
 
                        nd = rb_next(nd);
-                       __machine__remove_thread(machine, t, false);
+                       __machine__remove_thread(machine, trb, trb->thread, false);
                }
                up_write(&threads->lock);
        }
@@ -605,6 +621,7 @@ static struct thread *____machine__findnew_thread(struct machine *machine,
        struct rb_node **p = &threads->entries.rb_root.rb_node;
        struct rb_node *parent = NULL;
        struct thread *th;
+       struct thread_rb_node *nd;
        bool leftmost = true;
 
        th = threads__get_last_match(threads, machine, pid, tid);
@@ -613,7 +630,7 @@ static struct thread *____machine__findnew_thread(struct machine *machine,
 
        while (*p != NULL) {
                parent = *p;
-               th = rb_entry(parent, struct thread, rb_node);
+               th = rb_entry(parent, struct thread_rb_node, rb_node)->thread;
 
                if (th->tid == tid) {
                        threads__set_last_match(threads, th);
@@ -633,30 +650,39 @@ static struct thread *____machine__findnew_thread(struct machine *machine,
                return NULL;
 
        th = thread__new(pid, tid);
-       if (th != NULL) {
-               rb_link_node(&th->rb_node, parent, p);
-               rb_insert_color_cached(&th->rb_node, &threads->entries, leftmost);
+       if (th == NULL)
+               return NULL;
 
-               /*
-                * We have to initialize maps separately after rb tree is updated.
-                *
-                * The reason is that we call machine__findnew_thread
-                * within thread__init_maps to find the thread
-                * leader and that would screwed the rb tree.
-                */
-               if (thread__init_maps(th, machine)) {
-                       rb_erase_cached(&th->rb_node, &threads->entries);
-                       RB_CLEAR_NODE(&th->rb_node);
-                       thread__put(th);
-                       return NULL;
-               }
-               /*
-                * It is now in the rbtree, get a ref
-                */
-               thread__get(th);
-               threads__set_last_match(threads, th);
-               ++threads->nr;
+       nd = malloc(sizeof(*nd));
+       if (nd == NULL) {
+               thread__put(th);
+               return NULL;
+       }
+       nd->thread = th;
+
+       rb_link_node(&nd->rb_node, parent, p);
+       rb_insert_color_cached(&nd->rb_node, &threads->entries, leftmost);
+
+       /*
+        * We have to initialize maps separately after rb tree is updated.
+        *
+        * The reason is that we call machine__findnew_thread within
+        * thread__init_maps to find the thread leader and that would screwed
+        * the rb tree.
+        */
+       if (thread__init_maps(th, machine)) {
+               rb_erase_cached(&nd->rb_node, &threads->entries);
+               RB_CLEAR_NODE(&nd->rb_node);
+               free(nd);
+               thread__put(th);
+               return NULL;
        }
+       /*
+        * It is now in the rbtree, get a ref
+        */
+       thread__get(th);
+       threads__set_last_match(threads, th);
+       ++threads->nr;
 
        return th;
 }
@@ -1109,7 +1135,7 @@ size_t machine__fprintf(struct machine *machine, FILE *fp)
 
                for (nd = rb_first_cached(&threads->entries); nd;
                     nd = rb_next(nd)) {
-                       struct thread *pos = rb_entry(nd, struct thread, rb_node);
+                       struct thread *pos = rb_entry(nd, struct thread_rb_node, rb_node)->thread;
 
                        ret += thread__fprintf(pos, fp);
                }
@@ -2020,10 +2046,14 @@ out_problem:
        return 0;
 }
 
-static void __machine__remove_thread(struct machine *machine, struct thread *th, bool lock)
+static void __machine__remove_thread(struct machine *machine, struct thread_rb_node *nd,
+                                    struct thread *th, bool lock)
 {
        struct threads *threads = machine__threads(machine, th->tid);
 
+       if (!nd)
+               nd = thread_rb_node__find(th, &threads->entries.rb_root);
+
        if (threads->last_match == th)
                threads__set_last_match(threads, NULL);
 
@@ -2032,11 +2062,12 @@ static void __machine__remove_thread(struct machine *machine, struct thread *th,
 
        BUG_ON(refcount_read(&th->refcnt) == 0);
 
-       rb_erase_cached(&th->rb_node, &threads->entries);
-       RB_CLEAR_NODE(&th->rb_node);
+       thread__put(nd->thread);
+       rb_erase_cached(&nd->rb_node, &threads->entries);
+       RB_CLEAR_NODE(&nd->rb_node);
        --threads->nr;
 
-       thread__put(th);
+       free(nd);
 
        if (lock)
                up_write(&threads->lock);
@@ -2044,7 +2075,7 @@ static void __machine__remove_thread(struct machine *machine, struct thread *th,
 
 void machine__remove_thread(struct machine *machine, struct thread *th)
 {
-       return __machine__remove_thread(machine, th, true);
+       return __machine__remove_thread(machine, NULL, th, true);
 }
 
 int machine__process_fork_event(struct machine *machine, union perf_event *event,
@@ -3167,7 +3198,6 @@ int machine__for_each_thread(struct machine *machine,
 {
        struct threads *threads;
        struct rb_node *nd;
-       struct thread *thread;
        int rc = 0;
        int i;
 
@@ -3175,8 +3205,9 @@ int machine__for_each_thread(struct machine *machine,
                threads = &machine->threads[i];
                for (nd = rb_first_cached(&threads->entries); nd;
                     nd = rb_next(nd)) {
-                       thread = rb_entry(nd, struct thread, rb_node);
-                       rc = fn(thread, priv);
+                       struct thread_rb_node *trb = rb_entry(nd, struct thread_rb_node, rb_node);
+
+                       rc = fn(trb->thread, priv);
                        if (rc != 0)
                                return rc;
                }

diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
index d949bff..38d300e 100644 (file)
--- a/tools/perf/util/thread.c
+++ b/tools/perf/util/thread.c
@@ -66,7 +66,6 @@ struct thread *thread__new(pid_t pid, pid_t tid)
 
                list_add(&comm->list, &thread->comm_list);
                refcount_set(&thread->refcnt, 1);
-               RB_CLEAR_NODE(&thread->rb_node);
                /* Thread holds first ref to nsdata. */
                thread->nsinfo = nsinfo__new(pid);
                srccode_state_init(&thread->srccode_state);
@@ -84,8 +83,6 @@ void thread__delete(struct thread *thread)
        struct namespaces *namespaces, *tmp_namespaces;
        struct comm *comm, *tmp_comm;
 
-       BUG_ON(!RB_EMPTY_NODE(&thread->rb_node));
-
        thread_stack__free(thread);
 
        if (thread->maps) {

diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
index 8673781..3b3f9fb 100644 (file)
--- a/tools/perf/util/thread.h
+++ b/tools/perf/util/thread.h
@@ -29,8 +29,12 @@ struct lbr_stitch {
        struct callchain_cursor_node    *prev_lbr_cursor;
 };
 
+struct thread_rb_node {
+       struct rb_node rb_node;
+       struct thread *thread;
+};
+
 struct thread {
-       struct rb_node          rb_node;
        struct maps             *maps;
        pid_t                   pid_; /* Not all tools update this */
        pid_t                   tid;