diff options
| -rw-r--r-- | samples/Kconfig | 8 | ||||
| -rw-r--r-- | samples/Makefile | 1 | ||||
| -rw-r--r-- | samples/trace_events/Makefile | 2 | ||||
| -rw-r--r-- | samples/trace_events/trace_custom_sched.c | 271 |
4 files changed, 281 insertions, 1 deletions
diff --git a/samples/Kconfig b/samples/Kconfig index 22cc921ae291..10e021c72282 100644 --- a/samples/Kconfig +++ b/samples/Kconfig @@ -14,7 +14,13 @@ config SAMPLE_TRACE_EVENTS tristate "Build trace_events examples -- loadable modules only" depends on EVENT_TRACING && m help - This build trace event example modules. + This builds the trace event example module. + +config SAMPLE_TRACE_CUSTOM_EVENTS + tristate "Build custom trace event example -- loadable modules only" + depends on EVENT_TRACING && m + help + This builds the custom trace event example module. config SAMPLE_TRACE_PRINTK tristate "Build trace_printk module - tests various trace_printk formats" diff --git a/samples/Makefile b/samples/Makefile index 1ae4de99c983..448343e8faeb 100644 --- a/samples/Makefile +++ b/samples/Makefile @@ -20,6 +20,7 @@ obj-$(CONFIG_SAMPLE_RPMSG_CLIENT) += rpmsg/ subdir-$(CONFIG_SAMPLE_SECCOMP) += seccomp subdir-$(CONFIG_SAMPLE_TIMER) += timers obj-$(CONFIG_SAMPLE_TRACE_EVENTS) += trace_events/ +obj-$(CONFIG_SAMPLE_TRACE_CUSTOM_EVENTS) += trace_events/ obj-$(CONFIG_SAMPLE_TRACE_PRINTK) += trace_printk/ obj-$(CONFIG_SAMPLE_FTRACE_DIRECT) += ftrace/ obj-$(CONFIG_SAMPLE_FTRACE_DIRECT_MULTI) += ftrace/ diff --git a/samples/trace_events/Makefile b/samples/trace_events/Makefile index b78344e7bbed..e98afc447fe1 100644 --- a/samples/trace_events/Makefile +++ b/samples/trace_events/Makefile @@ -13,3 +13,5 @@ CFLAGS_trace-events-sample.o := -I$(src) obj-$(CONFIG_SAMPLE_TRACE_EVENTS) += trace-events-sample.o + +obj-$(CONFIG_SAMPLE_TRACE_CUSTOM_EVENTS) += trace_custom_sched.o diff --git a/samples/trace_events/trace_custom_sched.c b/samples/trace_events/trace_custom_sched.c new file mode 100644 index 000000000000..70a12c32ff99 --- /dev/null +++ b/samples/trace_events/trace_custom_sched.c @@ -0,0 +1,271 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * event tracer + * + * Copyright (C) 2022 Google Inc, Steven Rostedt <rostedt@goodmis.org> + */ + +#define pr_fmt(fmt) fmt + +#include <linux/trace_events.h> +#include <linux/version.h> +#include <linux/module.h> +#include <linux/sched.h> +#include <trace/events/sched.h> + +#define THIS_SYSTEM "custom_sched" + +#define SCHED_PRINT_FMT \ + C("prev_prio=%d next_pid=%d next_prio=%d", REC->prev_prio, REC->next_pid, \ + REC->next_prio) + +#define SCHED_WAKING_FMT \ + C("pid=%d prio=%d", REC->pid, REC->prio) + +#undef C +#define C(a, b...) a, b + +static struct trace_event_fields sched_switch_fields[] = { + { + .type = "unsigned short", + .name = "prev_prio", + .size = sizeof(short), + .align = __alignof__(short), + .is_signed = 0, + .filter_type = FILTER_OTHER, + }, + { + .type = "unsigned short", + .name = "next_prio", + .size = sizeof(short), + .align = __alignof__(short), + .is_signed = 0, + .filter_type = FILTER_OTHER, + }, + { + .type = "unsigned int", + .name = "next_prio", + .size = sizeof(int), + .align = __alignof__(int), + .is_signed = 0, + .filter_type = FILTER_OTHER, + }, + {} +}; + +struct sched_event { + struct trace_entry ent; + unsigned short prev_prio; + unsigned short next_prio; + unsigned int next_pid; +}; + +static struct trace_event_fields sched_waking_fields[] = { + { + .type = "unsigned int", + .name = "pid", + .size = sizeof(int), + .align = __alignof__(int), + .is_signed = 0, + .filter_type = FILTER_OTHER, + }, + { + .type = "unsigned short", + .name = "prio", + .size = sizeof(short), + .align = __alignof__(short), + .is_signed = 0, + .filter_type = FILTER_OTHER, + }, + {} +}; + +struct wake_event { + struct trace_entry ent; + unsigned int pid; + unsigned short prio; +}; + +static void sched_switch_probe(void *data, bool preempt, struct task_struct *prev, + struct task_struct *next) +{ + struct trace_event_file *trace_file = data; + struct trace_event_buffer fbuffer; + struct sched_event *entry; + + if (trace_trigger_soft_disabled(trace_file)) + return; + + entry = trace_event_buffer_reserve(&fbuffer, trace_file, + sizeof(*entry)); + + if (!entry) + return; + + entry->prev_prio = prev->prio; + entry->next_prio = next->prio; + entry->next_pid = next->pid; + + trace_event_buffer_commit(&fbuffer); +} + +static struct trace_event_class sched_switch_class = { + .system = THIS_SYSTEM, + .reg = trace_event_reg, + .fields_array = sched_switch_fields, + .fields = LIST_HEAD_INIT(sched_switch_class.fields), + .probe = sched_switch_probe, +}; + +static void sched_waking_probe(void *data, struct task_struct *t) +{ + struct trace_event_file *trace_file = data; + struct trace_event_buffer fbuffer; + struct wake_event *entry; + + if (trace_trigger_soft_disabled(trace_file)) + return; + + entry = trace_event_buffer_reserve(&fbuffer, trace_file, + sizeof(*entry)); + + if (!entry) + return; + + entry->prio = t->prio; + entry->pid = t->pid; + + trace_event_buffer_commit(&fbuffer); +} + +static struct trace_event_class sched_waking_class = { + .system = THIS_SYSTEM, + .reg = trace_event_reg, + .fields_array = sched_waking_fields, + .fields = LIST_HEAD_INIT(sched_waking_class.fields), + .probe = sched_waking_probe, +}; + +static enum print_line_t sched_switch_output(struct trace_iterator *iter, int flags, + struct trace_event *trace_event) +{ + struct trace_seq *s = &iter->seq; + struct sched_event *REC = (struct sched_event *)iter->ent; + int ret; + + ret = trace_raw_output_prep(iter, trace_event); + if (ret != TRACE_TYPE_HANDLED) + return ret; + + trace_seq_printf(s, SCHED_PRINT_FMT); + trace_seq_putc(s, '\n'); + + return trace_handle_return(s); +} + +static struct trace_event_functions sched_switch_funcs = { + .trace = sched_switch_output, +}; + +static enum print_line_t sched_waking_output(struct trace_iterator *iter, int flags, + struct trace_event *trace_event) +{ + struct trace_seq *s = &iter->seq; + struct wake_event *REC = (struct wake_event *)iter->ent; + int ret; + + ret = trace_raw_output_prep(iter, trace_event); + if (ret != TRACE_TYPE_HANDLED) + return ret; + + trace_seq_printf(s, SCHED_WAKING_FMT); + trace_seq_putc(s, '\n'); + + return trace_handle_return(s); +} + +static struct trace_event_functions sched_waking_funcs = { + .trace = sched_waking_output, +}; + +#undef C +#define C(a, b...) #a "," __stringify(b) + +static struct trace_event_call sched_switch_call = { + .class = &sched_switch_class, + .event = { + .funcs = &sched_switch_funcs, + }, + .print_fmt = SCHED_PRINT_FMT, + .module = THIS_MODULE, + .flags = TRACE_EVENT_FL_TRACEPOINT, +}; + +static struct trace_event_call sched_waking_call = { + .class = &sched_waking_class, + .event = { + .funcs = &sched_waking_funcs, + }, + .print_fmt = SCHED_WAKING_FMT, + .module = THIS_MODULE, + .flags = TRACE_EVENT_FL_TRACEPOINT, +}; + +static void fct(struct tracepoint *tp, void *priv) +{ + if (tp->name && strcmp(tp->name, "sched_switch") == 0) + sched_switch_call.tp = tp; + else if (tp->name && strcmp(tp->name, "sched_waking") == 0) + sched_waking_call.tp = tp; +} + +static int add_event(struct trace_event_call *call) +{ + int ret; + + ret = register_trace_event(&call->event); + if (WARN_ON(!ret)) + return -ENODEV; + + ret = trace_add_event_call(call); + if (WARN_ON(ret)) + unregister_trace_event(&call->event); + + return ret; +} + +static int __init trace_sched_init(void) +{ + int ret; + + check_trace_callback_type_sched_switch(sched_switch_probe); + check_trace_callback_type_sched_waking(sched_waking_probe); + + for_each_kernel_tracepoint(fct, NULL); + + ret = add_event(&sched_switch_call); + if (ret) + return ret; + + ret = add_event(&sched_waking_call); + if (ret) + trace_remove_event_call(&sched_switch_call); + + return ret; +} + +static void __exit trace_sched_exit(void) +{ + trace_set_clr_event(THIS_SYSTEM, "sched_switch", 0); + trace_set_clr_event(THIS_SYSTEM, "sched_waking", 0); + + trace_remove_event_call(&sched_switch_call); + trace_remove_event_call(&sched_waking_call); +} + +module_init(trace_sched_init); +module_exit(trace_sched_exit); + +MODULE_AUTHOR("Steven Rostedt"); +MODULE_DESCRIPTION("Custom scheduling events"); +MODULE_LICENSE("GPL"); |