On Tue, Feb 13, 2024 at 10:37 PM Ian Rogers <irogers@xxxxxxxxxx> wrote:
>
> Move threads out of machine and move thread_rb_node into the C
> file. This hides the implementation of threads from the rest of the
> code allowing for it to be refactored.
>
> Locking discipline is tightened up in this change.
Doesn't look like a simple code move. Can we split the locking
change from the move to make the reviewer's life a bit easier? :)
Thanks,
Namhyung
>
> Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
> ---
> tools/perf/util/Build | 1 +
> tools/perf/util/bpf_lock_contention.c | 8 +-
> tools/perf/util/machine.c | 287 ++++----------------------
> tools/perf/util/machine.h | 20 +-
> tools/perf/util/thread.c | 2 +-
> tools/perf/util/thread.h | 6 -
> tools/perf/util/threads.c | 244 ++++++++++++++++++++++
> tools/perf/util/threads.h | 35 ++++
> 8 files changed, 325 insertions(+), 278 deletions(-)
> create mode 100644 tools/perf/util/threads.c
> create mode 100644 tools/perf/util/threads.h
>
> diff --git a/tools/perf/util/Build b/tools/perf/util/Build
> index 8027f450fa3e..a0e8cd68d490 100644
> --- a/tools/perf/util/Build
> +++ b/tools/perf/util/Build
> @@ -71,6 +71,7 @@ perf-y += ordered-events.o
> perf-y += namespaces.o
> perf-y += comm.o
> perf-y += thread.o
> +perf-y += threads.o
> perf-y += thread_map.o
> perf-y += parse-events-flex.o
> perf-y += parse-events-bison.o
> diff --git a/tools/perf/util/bpf_lock_contention.c b/tools/perf/util/bpf_lock_contention.c
> index 31ff19afc20c..3992c8a9fd96 100644
> --- a/tools/perf/util/bpf_lock_contention.c
> +++ b/tools/perf/util/bpf_lock_contention.c
> @@ -210,7 +210,7 @@ static const char *lock_contention_get_name(struct lock_contention *con,
>
> /* do not update idle comm which contains CPU number */
> if (pid) {
> - struct thread *t = __machine__findnew_thread(machine, /*pid=*/-1, pid);
> + struct thread *t = machine__findnew_thread(machine, /*pid=*/-1, pid);
>
> if (t == NULL)
> return name;
> @@ -302,9 +302,9 @@ int lock_contention_read(struct lock_contention *con)
> return -1;
>
> if (con->aggr_mode == LOCK_AGGR_TASK) {
> - struct thread *idle = __machine__findnew_thread(machine,
> - /*pid=*/0,
> - /*tid=*/0);
> + struct thread *idle = machine__findnew_thread(machine,
> + /*pid=*/0,
> + /*tid=*/0);
> thread__set_comm(idle, "swapper", /*timestamp=*/0);
> }
>
> diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
> index e072b2115b64..e668a97255f8 100644
> --- a/tools/perf/util/machine.c
> +++ b/tools/perf/util/machine.c
> @@ -43,9 +43,6 @@
> #include <linux/string.h>
> #include <linux/zalloc.h>
>
> -static void __machine__remove_thread(struct machine *machine, struct thread_rb_node *nd,
> - struct thread *th, bool lock);
> -
> static struct dso *machine__kernel_dso(struct machine *machine)
> {
> return map__dso(machine->vmlinux_map);
> @@ -58,35 +55,6 @@ static void dsos__init(struct dsos *dsos)
> init_rwsem(&dsos->lock);
> }
>
> -static void machine__threads_init(struct machine *machine)
> -{
> - int i;
> -
> - for (i = 0; i < THREADS__TABLE_SIZE; i++) {
> - struct threads *threads = &machine->threads[i];
> - threads->entries = RB_ROOT_CACHED;
> - init_rwsem(&threads->lock);
> - threads->nr = 0;
> - threads->last_match = NULL;
> - }
> -}
> -
> -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)thread__tid(rb_entry(nd, struct thread_rb_node, rb_node)->thread);
> -}
> -
> -static struct thread_rb_node *thread_rb_node__find(const struct thread *th,
> - struct rb_root *tree)
> -{
> - pid_t to_find = thread__tid(th);
> - struct rb_node *nd = rb_find(&to_find, 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))
> @@ -120,7 +88,7 @@ int machine__init(struct machine *machine, const char *root_dir, pid_t pid)
> RB_CLEAR_NODE(&machine->rb_node);
> dsos__init(&machine->dsos);
>
> - machine__threads_init(machine);
> + threads__init(&machine->threads);
>
> machine->vdso_info = NULL;
> machine->env = NULL;
> @@ -221,27 +189,11 @@ static void dsos__exit(struct dsos *dsos)
>
> void machine__delete_threads(struct machine *machine)
> {
> - struct rb_node *nd;
> - int i;
> -
> - for (i = 0; i < THREADS__TABLE_SIZE; i++) {
> - struct threads *threads = &machine->threads[i];
> - down_write(&threads->lock);
> - nd = rb_first_cached(&threads->entries);
> - while (nd) {
> - struct thread_rb_node *trb = rb_entry(nd, struct thread_rb_node, rb_node);
> -
> - nd = rb_next(nd);
> - __machine__remove_thread(machine, trb, trb->thread, false);
> - }
> - up_write(&threads->lock);
> - }
> + threads__remove_all_threads(&machine->threads);
> }
>
> void machine__exit(struct machine *machine)
> {
> - int i;
> -
> if (machine == NULL)
> return;
>
> @@ -254,12 +206,7 @@ void machine__exit(struct machine *machine)
> zfree(&machine->current_tid);
> zfree(&machine->kallsyms_filename);
>
> - machine__delete_threads(machine);
> - for (i = 0; i < THREADS__TABLE_SIZE; i++) {
> - struct threads *threads = &machine->threads[i];
> -
> - exit_rwsem(&threads->lock);
> - }
> + threads__exit(&machine->threads);
> }
>
> void machine__delete(struct machine *machine)
> @@ -526,7 +473,7 @@ static void machine__update_thread_pid(struct machine *machine,
> if (thread__pid(th) == thread__tid(th))
> return;
>
> - leader = __machine__findnew_thread(machine, thread__pid(th), thread__pid(th));
> + leader = machine__findnew_thread(machine, thread__pid(th), thread__pid(th));
> if (!leader)
> goto out_err;
>
> @@ -560,160 +507,55 @@ static void machine__update_thread_pid(struct machine *machine,
> goto out_put;
> }
>
> -/*
> - * Front-end cache - TID lookups come in blocks,
> - * so most of the time we dont have to look up
> - * the full rbtree:
> - */
> -static struct thread*
> -__threads__get_last_match(struct threads *threads, struct machine *machine,
> - int pid, int tid)
> -{
> - struct thread *th;
> -
> - th = threads->last_match;
> - if (th != NULL) {
> - if (thread__tid(th) == tid) {
> - machine__update_thread_pid(machine, th, pid);
> - return thread__get(th);
> - }
> - thread__put(threads->last_match);
> - threads->last_match = NULL;
> - }
> -
> - return NULL;
> -}
> -
> -static struct thread*
> -threads__get_last_match(struct threads *threads, struct machine *machine,
> - int pid, int tid)
> -{
> - struct thread *th = NULL;
> -
> - if (perf_singlethreaded)
> - th = __threads__get_last_match(threads, machine, pid, tid);
> -
> - return th;
> -}
> -
> -static void
> -__threads__set_last_match(struct threads *threads, struct thread *th)
> -{
> - thread__put(threads->last_match);
> - threads->last_match = thread__get(th);
> -}
> -
> -static void
> -threads__set_last_match(struct threads *threads, struct thread *th)
> -{
> - if (perf_singlethreaded)
> - __threads__set_last_match(threads, th);
> -}
> -
> /*
> * Caller must eventually drop thread->refcnt returned with a successful
> * lookup/new thread inserted.
> */
> -static struct thread *____machine__findnew_thread(struct machine *machine,
> - struct threads *threads,
> - pid_t pid, pid_t tid,
> - bool create)
> +static struct thread *__machine__findnew_thread(struct machine *machine,
> + pid_t pid,
> + pid_t tid,
> + bool create)
> {
> - 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;
> + struct thread *th = threads__find(&machine->threads, tid);
> + bool created;
>
> - th = threads__get_last_match(threads, machine, pid, tid);
> - if (th)
> + if (th) {
> + machine__update_thread_pid(machine, th, pid);
> return th;
> -
> - while (*p != NULL) {
> - parent = *p;
> - th = rb_entry(parent, struct thread_rb_node, rb_node)->thread;
> -
> - if (thread__tid(th) == tid) {
> - threads__set_last_match(threads, th);
> - machine__update_thread_pid(machine, th, pid);
> - return thread__get(th);
> - }
> -
> - if (tid < thread__tid(th))
> - p = &(*p)->rb_left;
> - else {
> - p = &(*p)->rb_right;
> - leftmost = false;
> - }
> }
> -
> if (!create)
> return NULL;
>
> - th = thread__new(pid, tid);
> - if (th == NULL)
> - return NULL;
> -
> - 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)) {
> - pr_err("Thread init failed thread %d\n", pid);
> - 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
> - */
> - threads__set_last_match(threads, th);
> - ++threads->nr;
> -
> - return thread__get(th);
> -}
> + th = threads__findnew(&machine->threads, pid, tid, &created);
> + if (created) {
> + /*
> + * 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)) {
> + pr_err("Thread init failed thread %d\n", pid);
> + threads__remove(&machine->threads, th);
> + thread__put(th);
> + return NULL;
> + }
> + } else
> + machine__update_thread_pid(machine, th, pid);
>
> -struct thread *__machine__findnew_thread(struct machine *machine, pid_t pid, pid_t tid)
> -{
> - return ____machine__findnew_thread(machine, machine__threads(machine, tid), pid, tid, true);
> + return th;
> }
>
> -struct thread *machine__findnew_thread(struct machine *machine, pid_t pid,
> - pid_t tid)
> +struct thread *machine__findnew_thread(struct machine *machine, pid_t pid, pid_t tid)
> {
> - struct threads *threads = machine__threads(machine, tid);
> - struct thread *th;
> -
> - down_write(&threads->lock);
> - th = __machine__findnew_thread(machine, pid, tid);
> - up_write(&threads->lock);
> - return th;
> + return __machine__findnew_thread(machine, pid, tid, /*create=*/true);
> }
>
> -struct thread *machine__find_thread(struct machine *machine, pid_t pid,
> - pid_t tid)
> +struct thread *machine__find_thread(struct machine *machine, pid_t pid, pid_t tid)
> {
> - struct threads *threads = machine__threads(machine, tid);
> - struct thread *th;
> -
> - down_read(&threads->lock);
> - th = ____machine__findnew_thread(machine, threads, pid, tid, false);
> - up_read(&threads->lock);
> - return th;
> + return __machine__findnew_thread(machine, pid, tid, /*create=*/false);
> }
>
> /*
> @@ -1127,23 +969,13 @@ static int machine_fprintf_cb(struct thread *thread, void *data)
> return 0;
> }
>
> -static size_t machine__threads_nr(const struct machine *machine)
> -{
> - size_t nr = 0;
> -
> - for (int i = 0; i < THREADS__TABLE_SIZE; i++)
> - nr += machine->threads[i].nr;
> -
> - return nr;
> -}
> -
> size_t machine__fprintf(struct machine *machine, FILE *fp)
> {
> struct machine_fprintf_cb_args args = {
> .fp = fp,
> .printed = 0,
> };
> - size_t ret = fprintf(fp, "Threads: %zu\n", machine__threads_nr(machine));
> + size_t ret = fprintf(fp, "Threads: %zu\n", threads__nr(&machine->threads));
>
> machine__for_each_thread(machine, machine_fprintf_cb, &args);
> return ret + args.printed;
> @@ -2069,36 +1901,9 @@ int machine__process_mmap_event(struct machine *machine, union perf_event *event
> return 0;
> }
>
> -static void __machine__remove_thread(struct machine *machine, struct thread_rb_node *nd,
> - struct thread *th, bool lock)
> -{
> - struct threads *threads = machine__threads(machine, thread__tid(th));
> -
> - if (!nd)
> - nd = thread_rb_node__find(th, &threads->entries.rb_root);
> -
> - if (threads->last_match && RC_CHK_EQUAL(threads->last_match, th))
> - threads__set_last_match(threads, NULL);
> -
> - if (lock)
> - down_write(&threads->lock);
> -
> - BUG_ON(refcount_read(thread__refcnt(th)) == 0);
> -
> - thread__put(nd->thread);
> - rb_erase_cached(&nd->rb_node, &threads->entries);
> - RB_CLEAR_NODE(&nd->rb_node);
> - --threads->nr;
> -
> - free(nd);
> -
> - if (lock)
> - up_write(&threads->lock);
> -}
> -
> void machine__remove_thread(struct machine *machine, struct thread *th)
> {
> - return __machine__remove_thread(machine, NULL, th, true);
> + return threads__remove(&machine->threads, th);
> }
>
> int machine__process_fork_event(struct machine *machine, union perf_event *event,
> @@ -3232,23 +3037,7 @@ int machine__for_each_thread(struct machine *machine,
> int (*fn)(struct thread *thread, void *p),
> void *priv)
> {
> - struct threads *threads;
> - struct rb_node *nd;
> - int rc = 0;
> - int i;
> -
> - for (i = 0; i < THREADS__TABLE_SIZE; i++) {
> - threads = &machine->threads[i];
> - for (nd = rb_first_cached(&threads->entries); nd;
> - nd = rb_next(nd)) {
> - struct thread_rb_node *trb = rb_entry(nd, struct thread_rb_node, rb_node);
> -
> - rc = fn(trb->thread, priv);
> - if (rc != 0)
> - return rc;
> - }
> - }
> - return rc;
> + return threads__for_each_thread(&machine->threads, fn, priv);
> }
>
> int machines__for_each_thread(struct machines *machines,
> diff --git a/tools/perf/util/machine.h b/tools/perf/util/machine.h
> index b738ce84817b..e28c787616fe 100644
> --- a/tools/perf/util/machine.h
> +++ b/tools/perf/util/machine.h
> @@ -7,6 +7,7 @@
> #include "maps.h"
> #include "dsos.h"
> #include "rwsem.h"
> +#include "threads.h"
>
> struct addr_location;
> struct branch_stack;
> @@ -28,16 +29,6 @@ extern const char *ref_reloc_sym_names[];
>
> struct vdso_info;
>
> -#define THREADS__TABLE_BITS 8
> -#define THREADS__TABLE_SIZE (1 << THREADS__TABLE_BITS)
> -
> -struct threads {
> - struct rb_root_cached entries;
> - struct rw_semaphore lock;
> - unsigned int nr;
> - struct thread *last_match;
> -};
> -
> struct machine {
> struct rb_node rb_node;
> pid_t pid;
> @@ -48,7 +39,7 @@ struct machine {
> char *root_dir;
> char *mmap_name;
> char *kallsyms_filename;
> - struct threads threads[THREADS__TABLE_SIZE];
> + struct threads threads;
> struct vdso_info *vdso_info;
> struct perf_env *env;
> struct dsos dsos;
> @@ -69,12 +60,6 @@ struct machine {
> bool trampolines_mapped;
> };
>
> -static inline struct threads *machine__threads(struct machine *machine, pid_t tid)
> -{
> - /* Cast it to handle tid == -1 */
> - return &machine->threads[(unsigned int)tid % THREADS__TABLE_SIZE];
> -}
> -
> /*
> * The main kernel (vmlinux) map
> */
> @@ -220,7 +205,6 @@ bool machine__is(struct machine *machine, const char *arch);
> bool machine__normalized_is(struct machine *machine, const char *arch);
> int machine__nr_cpus_avail(struct machine *machine);
>
> -struct thread *__machine__findnew_thread(struct machine *machine, pid_t pid, pid_t tid);
> struct thread *machine__findnew_thread(struct machine *machine, pid_t pid, pid_t tid);
>
> struct dso *machine__findnew_dso_id(struct machine *machine, const char *filename, struct dso_id *id);
> diff --git a/tools/perf/util/thread.c b/tools/perf/util/thread.c
> index c59ab4d79163..1aa8962dcf52 100644
> --- a/tools/perf/util/thread.c
> +++ b/tools/perf/util/thread.c
> @@ -26,7 +26,7 @@ int thread__init_maps(struct thread *thread, struct machine *machine)
> if (pid == thread__tid(thread) || pid == -1) {
> thread__set_maps(thread, maps__new(machine));
> } else {
> - struct thread *leader = __machine__findnew_thread(machine, pid, pid);
> + struct thread *leader = machine__findnew_thread(machine, pid, pid);
>
> if (leader) {
> thread__set_maps(thread, maps__get(thread__maps(leader)));
> diff --git a/tools/perf/util/thread.h b/tools/perf/util/thread.h
> index 0df775b5c110..4b8f3e9e513b 100644
> --- a/tools/perf/util/thread.h
> +++ b/tools/perf/util/thread.h
> @@ -3,7 +3,6 @@
> #define __PERF_THREAD_H
>
> #include <linux/refcount.h>
> -#include <linux/rbtree.h>
> #include <linux/list.h>
> #include <stdio.h>
> #include <unistd.h>
> @@ -30,11 +29,6 @@ struct lbr_stitch {
> struct callchain_cursor_node *prev_lbr_cursor;
> };
>
> -struct thread_rb_node {
> - struct rb_node rb_node;
> - struct thread *thread;
> -};
> -
> DECLARE_RC_STRUCT(thread) {
> /** @maps: mmaps associated with this thread. */
> struct maps *maps;
> diff --git a/tools/perf/util/threads.c b/tools/perf/util/threads.c
> new file mode 100644
> index 000000000000..d984ec939c7b
> --- /dev/null
> +++ b/tools/perf/util/threads.c
> @@ -0,0 +1,244 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include "threads.h"
> +#include "machine.h"
> +#include "thread.h"
> +
> +struct thread_rb_node {
> + struct rb_node rb_node;
> + struct thread *thread;
> +};
> +
> +static struct threads_table_entry *threads__table(struct threads *threads, pid_t tid)
> +{
> + /* Cast it to handle tid == -1 */
> + return &threads->table[(unsigned int)tid % THREADS__TABLE_SIZE];
> +}
> +
> +void threads__init(struct threads *threads)
> +{
> + for (int i = 0; i < THREADS__TABLE_SIZE; i++) {
> + struct threads_table_entry *table = &threads->table[i];
> +
> + table->entries = RB_ROOT_CACHED;
> + init_rwsem(&table->lock);
> + table->nr = 0;
> + table->last_match = NULL;
> + }
> +}
> +
> +void threads__exit(struct threads *threads)
> +{
> + threads__remove_all_threads(threads);
> + for (int i = 0; i < THREADS__TABLE_SIZE; i++) {
> + struct threads_table_entry *table = &threads->table[i];
> +
> + exit_rwsem(&table->lock);
> + }
> +}
> +
> +size_t threads__nr(struct threads *threads)
> +{
> + size_t nr = 0;
> +
> + for (int i = 0; i < THREADS__TABLE_SIZE; i++) {
> + struct threads_table_entry *table = &threads->table[i];
> +
> + down_read(&table->lock);
> + nr += table->nr;
> + up_read(&table->lock);
> + }
> + return nr;
> +}
> +
> +/*
> + * Front-end cache - TID lookups come in blocks,
> + * so most of the time we dont have to look up
> + * the full rbtree:
> + */
> +static struct thread *__threads_table_entry__get_last_match(struct threads_table_entry *table,
> + pid_t tid)
> +{
> + struct thread *th, *res = NULL;
> +
> + th = table->last_match;
> + if (th != NULL) {
> + if (thread__tid(th) == tid)
> + res = thread__get(th);
> + }
> + return res;
> +}
> +
> +static void __threads_table_entry__set_last_match(struct threads_table_entry *table,
> + struct thread *th)
> +{
> + thread__put(table->last_match);
> + table->last_match = thread__get(th);
> +}
> +
> +static void threads_table_entry__set_last_match(struct threads_table_entry *table,
> + struct thread *th)
> +{
> + down_write(&table->lock);
> + __threads_table_entry__set_last_match(table, th);
> + up_write(&table->lock);
> +}
> +
> +struct thread *threads__find(struct threads *threads, pid_t tid)
> +{
> + struct threads_table_entry *table = threads__table(threads, tid);
> + struct rb_node **p;
> + struct thread *res = NULL;
> +
> + down_read(&table->lock);
> + res = __threads_table_entry__get_last_match(table, tid);
> + if (res)
> + return res;
> +
> + p = &table->entries.rb_root.rb_node;
> + while (*p != NULL) {
> + struct rb_node *parent = *p;
> + struct thread *th = rb_entry(parent, struct thread_rb_node, rb_node)->thread;
> +
> + if (thread__tid(th) == tid) {
> + res = thread__get(th);
> + break;
> + }
> +
> + if (tid < thread__tid(th))
> + p = &(*p)->rb_left;
> + else
> + p = &(*p)->rb_right;
> + }
> + up_read(&table->lock);
> + if (res)
> + threads_table_entry__set_last_match(table, res);
> + return res;
> +}
> +
> +struct thread *threads__findnew(struct threads *threads, pid_t pid, pid_t tid, bool *created)
> +{
> + struct threads_table_entry *table = threads__table(threads, tid);
> + struct rb_node **p;
> + struct rb_node *parent = NULL;
> + struct thread *res = NULL;
> + struct thread_rb_node *nd;
> + bool leftmost = true;
> +
> + *created = false;
> + down_write(&table->lock);
> + p = &table->entries.rb_root.rb_node;
> + while (*p != NULL) {
> + struct thread *th;
> +
> + parent = *p;
> + th = rb_entry(parent, struct thread_rb_node, rb_node)->thread;
> +
> + if (thread__tid(th) == tid) {
> + __threads_table_entry__set_last_match(table, th);
> + res = thread__get(th);
> + goto out_unlock;
> + }
> +
> + if (tid < thread__tid(th))
> + p = &(*p)->rb_left;
> + else {
> + leftmost = false;
> + p = &(*p)->rb_right;
> + }
> + }
> + nd = malloc(sizeof(*nd));
> + if (nd == NULL)
> + goto out_unlock;
> + res = thread__new(pid, tid);
> + if (!res)
> + free(nd);
> + else {
> + *created = true;
> + nd->thread = thread__get(res);
> + rb_link_node(&nd->rb_node, parent, p);
> + rb_insert_color_cached(&nd->rb_node, &table->entries, leftmost);
> + ++table->nr;
> + __threads_table_entry__set_last_match(table, res);
> + }
> +out_unlock:
> + up_write(&table->lock);
> + return res;
> +}
> +
> +void threads__remove_all_threads(struct threads *threads)
> +{
> + for (int i = 0; i < THREADS__TABLE_SIZE; i++) {
> + struct threads_table_entry *table = &threads->table[i];
> + struct rb_node *nd;
> +
> + down_write(&table->lock);
> + __threads_table_entry__set_last_match(table, NULL);
> + nd = rb_first_cached(&table->entries);
> + while (nd) {
> + struct thread_rb_node *trb = rb_entry(nd, struct thread_rb_node, rb_node);
> +
> + nd = rb_next(nd);
> + thread__put(trb->thread);
> + rb_erase_cached(&trb->rb_node, &table->entries);
> + RB_CLEAR_NODE(&trb->rb_node);
> + --table->nr;
> +
> + free(trb);
> + }
> + assert(table->nr == 0);
> + up_write(&table->lock);
> + }
> +}
> +
> +void threads__remove(struct threads *threads, struct thread *thread)
> +{
> + struct rb_node **p;
> + struct threads_table_entry *table = threads__table(threads, thread__tid(thread));
> + pid_t tid = thread__tid(thread);
> +
> + down_write(&table->lock);
> + if (table->last_match && RC_CHK_EQUAL(table->last_match, thread))
> + __threads_table_entry__set_last_match(table, NULL);
> +
> + p = &table->entries.rb_root.rb_node;
> + while (*p != NULL) {
> + struct rb_node *parent = *p;
> + struct thread_rb_node *nd = rb_entry(parent, struct thread_rb_node, rb_node);
> + struct thread *th = nd->thread;
> +
> + if (RC_CHK_EQUAL(th, thread)) {
> + thread__put(nd->thread);
> + rb_erase_cached(&nd->rb_node, &table->entries);
> + RB_CLEAR_NODE(&nd->rb_node);
> + --table->nr;
> + free(nd);
> + break;
> + }
> +
> + if (tid < thread__tid(th))
> + p = &(*p)->rb_left;
> + else
> + p = &(*p)->rb_right;
> + }
> + up_write(&table->lock);
> +}
> +
> +int threads__for_each_thread(struct threads *threads,
> + int (*fn)(struct thread *thread, void *data),
> + void *data)
> +{
> + for (int i = 0; i < THREADS__TABLE_SIZE; i++) {
> + struct threads_table_entry *table = &threads->table[i];
> + struct rb_node *nd;
> +
> + for (nd = rb_first_cached(&table->entries); nd; nd = rb_next(nd)) {
> + struct thread_rb_node *trb = rb_entry(nd, struct thread_rb_node, rb_node);
> + int rc = fn(trb->thread, data);
> +
> + if (rc != 0)
> + return rc;
> + }
> + }
> + return 0;
> +
> +}
> diff --git a/tools/perf/util/threads.h b/tools/perf/util/threads.h
> new file mode 100644
> index 000000000000..ed67de627578
> --- /dev/null
> +++ b/tools/perf/util/threads.h
> @@ -0,0 +1,35 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef __PERF_THREADS_H
> +#define __PERF_THREADS_H
> +
> +#include <linux/rbtree.h>
> +#include "rwsem.h"
> +
> +struct thread;
> +
> +#define THREADS__TABLE_BITS 8
> +#define THREADS__TABLE_SIZE (1 << THREADS__TABLE_BITS)
> +
> +struct threads_table_entry {
> + struct rb_root_cached entries;
> + struct rw_semaphore lock;
> + unsigned int nr;
> + struct thread *last_match;
> +};
> +
> +struct threads {
> + struct threads_table_entry table[THREADS__TABLE_SIZE];
> +};
> +
> +void threads__init(struct threads *threads);
> +void threads__exit(struct threads *threads);
> +size_t threads__nr(struct threads *threads);
> +struct thread *threads__find(struct threads *threads, pid_t tid);
> +struct thread *threads__findnew(struct threads *threads, pid_t pid, pid_t tid, bool *created);
> +void threads__remove_all_threads(struct threads *threads);
> +void threads__remove(struct threads *threads, struct thread *thread);
> +int threads__for_each_thread(struct threads *threads,
> + int (*fn)(struct thread *thread, void *data),
> + void *data);
> +
> +#endif /* __PERF_THREADS_H */
> --
> 2.43.0.687.g38aa6559b0-goog
>
