perf kwork: Add workqueue trace BPF support

Implements workqueue trace bpf function.

Test cases:

# perf kwork -k workqueue lat -b
Starting trace, Hit <Ctrl+C> to stop and report
^C
Kwork Name | Cpu | Avg delay | Count | Max delay | Max delay start | Max delay end |
--------------------------------------------------------------------------------------------------------------------------------
(w)addrconf_verify_work | 0002 | 5.856 ms | 1 | 5.856 ms | 111994.634313 s | 111994.640169 s |
(w)vmstat_update | 0001 | 1.247 ms | 1 | 1.247 ms | 111996.462651 s | 111996.463899 s |
(w)neigh_periodic_work | 0001 | 1.183 ms | 1 | 1.183 ms | 111996.462789 s | 111996.463973 s |
(w)neigh_managed_work | 0001 | 0.989 ms | 2 | 1.635 ms | 111996.462820 s | 111996.464455 s |
(w)wb_workfn | 0000 | 0.667 ms | 1 | 0.667 ms | 111996.384273 s | 111996.384940 s |
(w)bpf_prog_free_deferred | 0001 | 0.495 ms | 1 | 0.495 ms | 111986.314201 s | 111986.314696 s |
(w)mix_interrupt_randomness | 0002 | 0.421 ms | 6 | 0.749 ms | 111995.927750 s | 111995.928499 s |
(w)vmstat_shepherd | 0000 | 0.374 ms | 2 | 0.385 ms | 111991.265242 s | 111991.265627 s |
(w)e1000_watchdog | 0002 | 0.356 ms | 5 | 0.390 ms | 111994.528380 s | 111994.528770 s |
(w)vmstat_update | 0000 | 0.231 ms | 2 | 0.365 ms | 111996.384407 s | 111996.384772 s |
(w)flush_to_ldisc | 0006 | 0.165 ms | 1 | 0.165 ms | 111995.930606 s | 111995.930771 s |
(w)flush_to_ldisc | 0000 | 0.094 ms | 2 | 0.095 ms | 111996.460453 s | 111996.460548 s |
--------------------------------------------------------------------------------------------------------------------------------

# perf kwork -k workqueue rep -b
Starting trace, Hit <Ctrl+C> to stop and report
^C
Kwork Name | Cpu | Total Runtime | Count | Max runtime | Max runtime start | Max runtime end |
--------------------------------------------------------------------------------------------------------------------------------
(w)e1000_watchdog | 0002 | 0.627 ms | 2 | 0.324 ms | 112002.720665 s | 112002.720989 s |
(w)flush_to_ldisc | 0007 | 0.598 ms | 2 | 0.534 ms | 112000.875226 s | 112000.875761 s |
(w)wq_barrier_func | 0007 | 0.492 ms | 1 | 0.492 ms | 112000.876981 s | 112000.877473 s |
(w)flush_to_ldisc | 0007 | 0.281 ms | 1 | 0.281 ms | 112005.826882 s | 112005.827163 s |
(w)mix_interrupt_randomness | 0002 | 0.229 ms | 3 | 0.102 ms | 112005.825671 s | 112005.825774 s |
(w)vmstat_shepherd | 0000 | 0.202 ms | 1 | 0.202 ms | 112001.504511 s | 112001.504713 s |
(w)bpf_prog_free_deferred | 0001 | 0.181 ms | 1 | 0.181 ms | 112000.883251 s | 112000.883432 s |
(w)wb_workfn | 0007 | 0.130 ms | 1 | 0.130 ms | 112001.505195 s | 112001.505325 s |
(w)vmstat_update | 0000 | 0.053 ms | 1 | 0.053 ms | 112001.504763 s | 112001.504815 s |
--------------------------------------------------------------------------------------------------------------------------------

Signed-off-by: Yang Jihong <[e-mail]>
Tested-by: Arnaldo Carvalho de Melo <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Ingo Molnar <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Mark Rutland <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Paul Clarke <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/bpf_kwork.c

···
 	.get_work_name = get_work_name_from_map,
 };
 
+static void workqueue_load_prepare(struct perf_kwork *kwork)
+{
+	if (kwork->report == KWORK_REPORT_RUNTIME) {
+		bpf_program__set_autoload(skel->progs.report_workqueue_execute_start, true);
+		bpf_program__set_autoload(skel->progs.report_workqueue_execute_end, true);
+	} else if (kwork->report == KWORK_REPORT_LATENCY) {
+		bpf_program__set_autoload(skel->progs.latency_workqueue_activate_work, true);
+		bpf_program__set_autoload(skel->progs.latency_workqueue_execute_start, true);
+	}
+}
+
+static struct kwork_class_bpf kwork_workqueue_bpf = {
+	.load_prepare  = workqueue_load_prepare,
+	.get_work_name = get_work_name_from_map,
+};
+
 static struct kwork_class_bpf *
 kwork_class_bpf_supported_list[KWORK_CLASS_MAX] = {
 	[KWORK_CLASS_IRQ]       = &kwork_irq_bpf,
 	[KWORK_CLASS_SOFTIRQ]   = &kwork_softirq_bpf,
-	[KWORK_CLASS_WORKQUEUE] = NULL,
+	[KWORK_CLASS_WORKQUEUE] = &kwork_workqueue_bpf,
 };
 
 static bool valid_kwork_class_type(enum kwork_class_type type)

tools/perf/util/bpf_skel/kwork_trace.bpf.c

···
 		bpf_map_update_elem(map, key, name, BPF_ANY);
 }
 
+static __always_inline int update_timestart(void *map, struct work_key *key)
+{
+	if (!trace_event_match(key, NULL))
+		return 0;
+
+	do_update_timestart(map, key);
+	return 0;
+}
+
 static __always_inline int update_timestart_and_name(void *time_map,
 						     void *names_map,
 						     struct work_key *key,
···
 		return 0;
 
 	do_update_timeend(report_map, time_map, key);
+
+	return 0;
+}
+
+static __always_inline int update_timeend_and_name(void *report_map,
+						   void *time_map,
+						   void *names_map,
+						   struct work_key *key,
+						   char *name)
+{
+	if (!trace_event_match(key, name))
+		return 0;
+
+	do_update_timeend(report_map, time_map, key);
+	do_update_name(names_map, key, name);
 
 	return 0;
 }
···
 	};
 
 	return update_timeend(&perf_kwork_report, &perf_kwork_time, &key);
+}
+
+SEC("tracepoint/workqueue/workqueue_execute_start")
+int report_workqueue_execute_start(struct trace_event_raw_workqueue_execute_start *ctx)
+{
+	struct work_key key = {
+		.type = KWORK_CLASS_WORKQUEUE,
+		.cpu  = bpf_get_smp_processor_id(),
+		.id   = (__u64)ctx->work,
+	};
+
+	return update_timestart(&perf_kwork_time, &key);
+}
+
+SEC("tracepoint/workqueue/workqueue_execute_end")
+int report_workqueue_execute_end(struct trace_event_raw_workqueue_execute_end *ctx)
+{
+	char name[MAX_KWORKNAME];
+	struct work_key key = {
+		.type = KWORK_CLASS_WORKQUEUE,
+		.cpu  = bpf_get_smp_processor_id(),
+		.id   = (__u64)ctx->work,
+	};
+	unsigned long long func_addr = (unsigned long long)ctx->function;
+
+	__builtin_memset(name, 0, sizeof(name));
+	bpf_snprintf(name, sizeof(name), "%ps", &func_addr, sizeof(func_addr));
+
+	return update_timeend_and_name(&perf_kwork_report, &perf_kwork_time,
+				       &perf_kwork_names, &key, name);
+}
+
+SEC("tracepoint/workqueue/workqueue_activate_work")
+int latency_workqueue_activate_work(struct trace_event_raw_workqueue_activate_work *ctx)
+{
+	struct work_key key = {
+		.type = KWORK_CLASS_WORKQUEUE,
+		.cpu  = bpf_get_smp_processor_id(),
+		.id   = (__u64)ctx->work,
+	};
+
+	return update_timestart(&perf_kwork_time, &key);
+}
+
+SEC("tracepoint/workqueue/workqueue_execute_start")
+int latency_workqueue_execute_start(struct trace_event_raw_workqueue_execute_start *ctx)
+{
+	char name[MAX_KWORKNAME];
+	struct work_key key = {
+		.type = KWORK_CLASS_WORKQUEUE,
+		.cpu  = bpf_get_smp_processor_id(),
+		.id   = (__u64)ctx->work,
+	};
+	unsigned long long func_addr = (unsigned long long)ctx->function;
+
+	__builtin_memset(name, 0, sizeof(name));
+	bpf_snprintf(name, sizeof(name), "%ps", &func_addr, sizeof(func_addr));
+
+	return update_timeend_and_name(&perf_kwork_report, &perf_kwork_time,
+				       &perf_kwork_names, &key, name);
 }
 
 char LICENSE[] SEC("license") = "Dual BSD/GPL";