From 01e3e710a9265fb7092efd67243d7b6dd6e2548a Mon Sep 17 00:00:00 2001 From: David Sharp Date: Thu, 7 Jun 2012 16:46:24 -0700 Subject: tracing: Trivial cleanup Remove ftrace_format_syscall() declaration; it is neither defined nor used. Also update a comment and formatting. Link: http://lkml.kernel.org/r/1339112785-21806-1-git-send-email-vnagarnaik@google.com Signed-off-by: David Sharp Signed-off-by: Vaibhav Nagarnaik Signed-off-by: Steven Rostedt --- include/trace/syscall.h | 2 -- 1 file changed, 2 deletions(-) (limited to 'include/trace') diff --git a/include/trace/syscall.h b/include/trace/syscall.h index 31966a4fb8cc..0c95796177d7 100644 --- a/include/trace/syscall.h +++ b/include/trace/syscall.h @@ -39,8 +39,6 @@ extern int reg_event_syscall_enter(struct ftrace_event_call *call); extern void unreg_event_syscall_enter(struct ftrace_event_call *call); extern int reg_event_syscall_exit(struct ftrace_event_call *call); extern void unreg_event_syscall_exit(struct ftrace_event_call *call); -extern int -ftrace_format_syscall(struct ftrace_event_call *call, struct trace_seq *s); enum print_line_t print_syscall_enter(struct trace_iterator *iter, int flags, struct trace_event *event); enum print_line_t print_syscall_exit(struct trace_iterator *iter, int flags, -- cgit v1.2.3-59-g8ed1b From 6f86ab9fcaef122abb837819139eadac1a0ca966 Mon Sep 17 00:00:00 2001 From: Vaibhav Nagarnaik Date: Thu, 7 Jun 2012 16:46:25 -0700 Subject: tracing: Cleanup unnecessary function declarations The functions defined in include/trace/syscalls.h are not used directly since struct ftrace_event_class was introduced. Remove them from the header file and rearrange the ftrace_event_class declarations in trace_syscalls.c. Link: http://lkml.kernel.org/r/1339112785-21806-2-git-send-email-vnagarnaik@google.com Signed-off-by: Vaibhav Nagarnaik Signed-off-by: Steven Rostedt --- include/trace/syscall.h | 21 --------------- kernel/trace/trace_syscalls.c | 61 ++++++++++++++++++++----------------------- 2 files changed, 29 insertions(+), 53 deletions(-) (limited to 'include/trace') diff --git a/include/trace/syscall.h b/include/trace/syscall.h index 0c95796177d7..84bc4197e736 100644 --- a/include/trace/syscall.h +++ b/include/trace/syscall.h @@ -31,25 +31,4 @@ struct syscall_metadata { struct ftrace_event_call *exit_event; }; -#ifdef CONFIG_FTRACE_SYSCALLS -extern unsigned long arch_syscall_addr(int nr); -extern int init_syscall_trace(struct ftrace_event_call *call); - -extern int reg_event_syscall_enter(struct ftrace_event_call *call); -extern void unreg_event_syscall_enter(struct ftrace_event_call *call); -extern int reg_event_syscall_exit(struct ftrace_event_call *call); -extern void unreg_event_syscall_exit(struct ftrace_event_call *call); -enum print_line_t print_syscall_enter(struct trace_iterator *iter, int flags, - struct trace_event *event); -enum print_line_t print_syscall_exit(struct trace_iterator *iter, int flags, - struct trace_event *event); -#endif - -#ifdef CONFIG_PERF_EVENTS -int perf_sysenter_enable(struct ftrace_event_call *call); -void perf_sysenter_disable(struct ftrace_event_call *call); -int perf_sysexit_enable(struct ftrace_event_call *call); -void perf_sysexit_disable(struct ftrace_event_call *call); -#endif - #endif /* _TRACE_SYSCALL_H */ diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index 2485a7d09b11..7609dd6714c2 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -21,9 +21,6 @@ static int syscall_enter_register(struct ftrace_event_call *event, static int syscall_exit_register(struct ftrace_event_call *event, enum trace_reg type, void *data); -static int syscall_enter_define_fields(struct ftrace_event_call *call); -static int syscall_exit_define_fields(struct ftrace_event_call *call); - static struct list_head * syscall_get_enter_fields(struct ftrace_event_call *call) { @@ -32,30 +29,6 @@ syscall_get_enter_fields(struct ftrace_event_call *call) return &entry->enter_fields; } -struct trace_event_functions enter_syscall_print_funcs = { - .trace = print_syscall_enter, -}; - -struct trace_event_functions exit_syscall_print_funcs = { - .trace = print_syscall_exit, -}; - -struct ftrace_event_class event_class_syscall_enter = { - .system = "syscalls", - .reg = syscall_enter_register, - .define_fields = syscall_enter_define_fields, - .get_fields = syscall_get_enter_fields, - .raw_init = init_syscall_trace, -}; - -struct ftrace_event_class event_class_syscall_exit = { - .system = "syscalls", - .reg = syscall_exit_register, - .define_fields = syscall_exit_define_fields, - .fields = LIST_HEAD_INIT(event_class_syscall_exit.fields), - .raw_init = init_syscall_trace, -}; - extern struct syscall_metadata *__start_syscalls_metadata[]; extern struct syscall_metadata *__stop_syscalls_metadata[]; @@ -432,7 +405,7 @@ void unreg_event_syscall_exit(struct ftrace_event_call *call) mutex_unlock(&syscall_trace_lock); } -int init_syscall_trace(struct ftrace_event_call *call) +static int init_syscall_trace(struct ftrace_event_call *call) { int id; int num; @@ -457,6 +430,30 @@ int init_syscall_trace(struct ftrace_event_call *call) return id; } +struct trace_event_functions enter_syscall_print_funcs = { + .trace = print_syscall_enter, +}; + +struct trace_event_functions exit_syscall_print_funcs = { + .trace = print_syscall_exit, +}; + +struct ftrace_event_class event_class_syscall_enter = { + .system = "syscalls", + .reg = syscall_enter_register, + .define_fields = syscall_enter_define_fields, + .get_fields = syscall_get_enter_fields, + .raw_init = init_syscall_trace, +}; + +struct ftrace_event_class event_class_syscall_exit = { + .system = "syscalls", + .reg = syscall_exit_register, + .define_fields = syscall_exit_define_fields, + .fields = LIST_HEAD_INIT(event_class_syscall_exit.fields), + .raw_init = init_syscall_trace, +}; + unsigned long __init __weak arch_syscall_addr(int nr) { return (unsigned long)sys_call_table[nr]; @@ -537,7 +534,7 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id) perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL); } -int perf_sysenter_enable(struct ftrace_event_call *call) +static int perf_sysenter_enable(struct ftrace_event_call *call) { int ret = 0; int num; @@ -558,7 +555,7 @@ int perf_sysenter_enable(struct ftrace_event_call *call) return ret; } -void perf_sysenter_disable(struct ftrace_event_call *call) +static void perf_sysenter_disable(struct ftrace_event_call *call) { int num; @@ -615,7 +612,7 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret) perf_trace_buf_submit(rec, size, rctx, 0, 1, regs, head, NULL); } -int perf_sysexit_enable(struct ftrace_event_call *call) +static int perf_sysexit_enable(struct ftrace_event_call *call) { int ret = 0; int num; @@ -636,7 +633,7 @@ int perf_sysexit_enable(struct ftrace_event_call *call) return ret; } -void perf_sysexit_disable(struct ftrace_event_call *call) +static void perf_sysexit_disable(struct ftrace_event_call *call) { int num; -- cgit v1.2.3-59-g8ed1b From 0d5c6e1c19bab82fad4837108c2902f557d62a04 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Thu, 1 Nov 2012 20:54:21 -0400 Subject: tracing: Use irq_work for wake ups and remove *_nowake_*() functions Have the ring buffer commit function use the irq_work infrastructure to wake up any waiters waiting on the ring buffer for new data. The irq_work was created for such a purpose, where doing the actual wake up at the time of adding data is too dangerous, as an event or function trace may be in the midst of the work queue locks and cause deadlocks. The irq_work will either delay the action to the next timer interrupt, or trigger an IPI to itself forcing an interrupt to do the work (in a safe location). With irq_work, all ring buffer commits can safely do wakeups, removing the need for the ring buffer commit "nowake" variants, which were used by events and function tracing. All commits can now safely use the normal commit, and the "nowake" variants can be removed. Cc: Peter Zijlstra Signed-off-by: Steven Rostedt --- include/linux/ftrace_event.h | 14 ++--- include/trace/ftrace.h | 3 +- kernel/trace/Kconfig | 1 + kernel/trace/trace.c | 121 +++++++++++++++++++++----------------- kernel/trace/trace.h | 5 -- kernel/trace/trace_events.c | 2 +- kernel/trace/trace_kprobe.c | 8 +-- kernel/trace/trace_sched_switch.c | 2 +- kernel/trace/trace_selftest.c | 1 + 9 files changed, 84 insertions(+), 73 deletions(-) (limited to 'include/trace') diff --git a/include/linux/ftrace_event.h b/include/linux/ftrace_event.h index 642928cf57b4..b80c8ddfbbdc 100644 --- a/include/linux/ftrace_event.h +++ b/include/linux/ftrace_event.h @@ -127,13 +127,13 @@ trace_current_buffer_lock_reserve(struct ring_buffer **current_buffer, void trace_current_buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event, unsigned long flags, int pc); -void trace_nowake_buffer_unlock_commit(struct ring_buffer *buffer, - struct ring_buffer_event *event, - unsigned long flags, int pc); -void trace_nowake_buffer_unlock_commit_regs(struct ring_buffer *buffer, - struct ring_buffer_event *event, - unsigned long flags, int pc, - struct pt_regs *regs); +void trace_buffer_unlock_commit(struct ring_buffer *buffer, + struct ring_buffer_event *event, + unsigned long flags, int pc); +void trace_buffer_unlock_commit_regs(struct ring_buffer *buffer, + struct ring_buffer_event *event, + unsigned long flags, int pc, + struct pt_regs *regs); void trace_current_buffer_discard_commit(struct ring_buffer *buffer, struct ring_buffer_event *event); diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index a763888a36f9..698f2a890322 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -545,8 +545,7 @@ ftrace_raw_event_##call(void *__data, proto) \ { assign; } \ \ if (!filter_current_check_discard(buffer, event_call, entry, event)) \ - trace_nowake_buffer_unlock_commit(buffer, \ - event, irq_flags, pc); \ + trace_buffer_unlock_commit(buffer, event, irq_flags, pc); \ } /* * The ftrace_test_probe is compiled out, it is only here as a build time check diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 4cea4f41c1d9..5d89335a485f 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -119,6 +119,7 @@ config TRACING select BINARY_PRINTF select EVENT_TRACING select TRACE_CLOCK + select IRQ_WORK config GENERIC_TRACER bool diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index d5cbc0d3f209..37d1c703e3ec 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -19,6 +19,7 @@ #include #include #include +#include #include #include #include @@ -84,6 +85,14 @@ static int dummy_set_flag(u32 old_flags, u32 bit, int set) */ static DEFINE_PER_CPU(bool, trace_cmdline_save); +/* + * When a reader is waiting for data, then this variable is + * set to true. + */ +static bool trace_wakeup_needed; + +static struct irq_work trace_work_wakeup; + /* * Kill all tracing for good (never come back). * It is initialized to 1 but will turn to zero if the initialization @@ -329,12 +338,18 @@ unsigned long trace_flags = TRACE_ITER_PRINT_PARENT | TRACE_ITER_PRINTK | static int trace_stop_count; static DEFINE_RAW_SPINLOCK(tracing_start_lock); -static void wakeup_work_handler(struct work_struct *work) +/** + * trace_wake_up - wake up tasks waiting for trace input + * + * Schedules a delayed work to wake up any task that is blocked on the + * trace_wait queue. These is used with trace_poll for tasks polling the + * trace. + */ +static void trace_wake_up(struct irq_work *work) { - wake_up(&trace_wait); -} + wake_up_all(&trace_wait); -static DECLARE_DELAYED_WORK(wakeup_work, wakeup_work_handler); +} /** * tracing_on - enable tracing buffers @@ -389,22 +404,6 @@ int tracing_is_on(void) } EXPORT_SYMBOL_GPL(tracing_is_on); -/** - * trace_wake_up - wake up tasks waiting for trace input - * - * Schedules a delayed work to wake up any task that is blocked on the - * trace_wait queue. These is used with trace_poll for tasks polling the - * trace. - */ -void trace_wake_up(void) -{ - const unsigned long delay = msecs_to_jiffies(2); - - if (trace_flags & TRACE_ITER_BLOCK) - return; - schedule_delayed_work(&wakeup_work, delay); -} - static int __init set_buf_size(char *str) { unsigned long buf_size; @@ -753,6 +752,40 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) } #endif /* CONFIG_TRACER_MAX_TRACE */ +static void default_wait_pipe(struct trace_iterator *iter) +{ + DEFINE_WAIT(wait); + + prepare_to_wait(&trace_wait, &wait, TASK_INTERRUPTIBLE); + + /* + * The events can happen in critical sections where + * checking a work queue can cause deadlocks. + * After adding a task to the queue, this flag is set + * only to notify events to try to wake up the queue + * using irq_work. + * + * We don't clear it even if the buffer is no longer + * empty. The flag only causes the next event to run + * irq_work to do the work queue wake up. The worse + * that can happen if we race with !trace_empty() is that + * an event will cause an irq_work to try to wake up + * an empty queue. + * + * There's no reason to protect this flag either, as + * the work queue and irq_work logic will do the necessary + * synchronization for the wake ups. The only thing + * that is necessary is that the wake up happens after + * a task has been queued. It's OK for spurious wake ups. + */ + trace_wakeup_needed = true; + + if (trace_empty(iter)) + schedule(); + + finish_wait(&trace_wait, &wait); +} + /** * register_tracer - register a tracer with the ftrace system. * @type - the plugin for the tracer @@ -1156,30 +1189,32 @@ void __buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event) { __this_cpu_write(trace_cmdline_save, true); + if (trace_wakeup_needed) { + trace_wakeup_needed = false; + /* irq_work_queue() supplies it's own memory barriers */ + irq_work_queue(&trace_work_wakeup); + } ring_buffer_unlock_commit(buffer, event); } static inline void __trace_buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event, - unsigned long flags, int pc, - int wake) + unsigned long flags, int pc) { __buffer_unlock_commit(buffer, event); ftrace_trace_stack(buffer, flags, 6, pc); ftrace_trace_userstack(buffer, flags, pc); - - if (wake) - trace_wake_up(); } void trace_buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event, unsigned long flags, int pc) { - __trace_buffer_unlock_commit(buffer, event, flags, pc, 1); + __trace_buffer_unlock_commit(buffer, event, flags, pc); } +EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit); struct ring_buffer_event * trace_current_buffer_lock_reserve(struct ring_buffer **current_rb, @@ -1196,29 +1231,21 @@ void trace_current_buffer_unlock_commit(struct ring_buffer *buffer, struct ring_buffer_event *event, unsigned long flags, int pc) { - __trace_buffer_unlock_commit(buffer, event, flags, pc, 1); + __trace_buffer_unlock_commit(buffer, event, flags, pc); } EXPORT_SYMBOL_GPL(trace_current_buffer_unlock_commit); -void trace_nowake_buffer_unlock_commit(struct ring_buffer *buffer, - struct ring_buffer_event *event, - unsigned long flags, int pc) -{ - __trace_buffer_unlock_commit(buffer, event, flags, pc, 0); -} -EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit); - -void trace_nowake_buffer_unlock_commit_regs(struct ring_buffer *buffer, - struct ring_buffer_event *event, - unsigned long flags, int pc, - struct pt_regs *regs) +void trace_buffer_unlock_commit_regs(struct ring_buffer *buffer, + struct ring_buffer_event *event, + unsigned long flags, int pc, + struct pt_regs *regs) { __buffer_unlock_commit(buffer, event); ftrace_trace_stack_regs(buffer, flags, 0, pc, regs); ftrace_trace_userstack(buffer, flags, pc); } -EXPORT_SYMBOL_GPL(trace_nowake_buffer_unlock_commit_regs); +EXPORT_SYMBOL_GPL(trace_buffer_unlock_commit_regs); void trace_current_buffer_discard_commit(struct ring_buffer *buffer, struct ring_buffer_event *event) @@ -3354,19 +3381,6 @@ tracing_poll_pipe(struct file *filp, poll_table *poll_table) } } - -void default_wait_pipe(struct trace_iterator *iter) -{ - DEFINE_WAIT(wait); - - prepare_to_wait(&trace_wait, &wait, TASK_INTERRUPTIBLE); - - if (trace_empty(iter)) - schedule(); - - finish_wait(&trace_wait, &wait); -} - /* * This is a make-shift waitqueue. * A tracer might use this callback on some rare cases: @@ -5107,6 +5121,7 @@ __init static int tracer_alloc_buffers(void) #endif trace_init_cmdlines(); + init_irq_work(&trace_work_wakeup, trace_wake_up); register_tracer(&nop_trace); current_trace = &nop_trace; diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index 3e8a176f64e6..55010ed175f0 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -327,7 +327,6 @@ trace_buffer_iter(struct trace_iterator *iter, int cpu) int tracer_init(struct tracer *t, struct trace_array *tr); int tracing_is_enabled(void); -void trace_wake_up(void); void tracing_reset(struct trace_array *tr, int cpu); void tracing_reset_online_cpus(struct trace_array *tr); void tracing_reset_current(int cpu); @@ -349,9 +348,6 @@ trace_buffer_lock_reserve(struct ring_buffer *buffer, unsigned long len, unsigned long flags, int pc); -void trace_buffer_unlock_commit(struct ring_buffer *buffer, - struct ring_buffer_event *event, - unsigned long flags, int pc); struct trace_entry *tracing_get_trace_entry(struct trace_array *tr, struct trace_array_cpu *data); @@ -370,7 +366,6 @@ void trace_init_global_iter(struct trace_iterator *iter); void tracing_iter_reset(struct trace_iterator *iter, int cpu); -void default_wait_pipe(struct trace_iterator *iter); void poll_wait_pipe(struct trace_iterator *iter); void ftrace(struct trace_array *tr, diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index cb2df3b70f7f..880073d0b946 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1760,7 +1760,7 @@ function_test_events_call(unsigned long ip, unsigned long parent_ip, entry->ip = ip; entry->parent_ip = parent_ip; - trace_nowake_buffer_unlock_commit(buffer, event, flags, pc); + trace_buffer_unlock_commit(buffer, event, flags, pc); out: atomic_dec(&per_cpu(ftrace_test_event_disable, cpu)); diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 5a3c533ef060..1865d5f76538 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -751,8 +751,8 @@ static __kprobes void kprobe_trace_func(struct kprobe *kp, struct pt_regs *regs) store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize); if (!filter_current_check_discard(buffer, call, entry, event)) - trace_nowake_buffer_unlock_commit_regs(buffer, event, - irq_flags, pc, regs); + trace_buffer_unlock_commit_regs(buffer, event, + irq_flags, pc, regs); } /* Kretprobe handler */ @@ -784,8 +784,8 @@ static __kprobes void kretprobe_trace_func(struct kretprobe_instance *ri, store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize); if (!filter_current_check_discard(buffer, call, entry, event)) - trace_nowake_buffer_unlock_commit_regs(buffer, event, - irq_flags, pc, regs); + trace_buffer_unlock_commit_regs(buffer, event, + irq_flags, pc, regs); } /* Event entry printers */ diff --git a/kernel/trace/trace_sched_switch.c b/kernel/trace/trace_sched_switch.c index b0a136ac382a..3374c792ccd8 100644 --- a/kernel/trace/trace_sched_switch.c +++ b/kernel/trace/trace_sched_switch.c @@ -102,7 +102,7 @@ tracing_sched_wakeup_trace(struct trace_array *tr, entry->next_cpu = task_cpu(wakee); if (!filter_check_discard(call, entry, buffer, event)) - trace_nowake_buffer_unlock_commit(buffer, event, flags, pc); + trace_buffer_unlock_commit(buffer, event, flags, pc); } static void diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c index 091b815f7b0a..47623169a815 100644 --- a/kernel/trace/trace_selftest.c +++ b/kernel/trace/trace_selftest.c @@ -1094,6 +1094,7 @@ trace_selftest_startup_wakeup(struct tracer *trace, struct trace_array *tr) tracing_stop(); /* check both trace buffers */ ret = trace_test_buffer(tr, NULL); + printk("ret = %d\n", ret); if (!ret) ret = trace_test_buffer(&max_tr, &count); -- cgit v1.2.3-59-g8ed1b From 1c7d66732458dc187008e3f5b2f71e019e320fc2 Mon Sep 17 00:00:00 2001 From: Shan Wei Date: Sat, 3 Nov 2012 12:38:33 +0800 Subject: tracing: Kill unused and puzzled sample code in ftrace.h When doing per-cpu helper optimizing work, find that this code is so puzzled. 1. It's mark as comment text, maybe a sample function for guidelines or a todo work. 2. But, this sample code is odd where struct perf_trace_buf is nonexistent. commit ce71b9 delete struct perf_trace_buf definition. Author: Frederic Weisbecker Date: Sun Nov 22 05:26:55 2009 +0100 tracing: Use the perf recursion protection from trace event Is it necessary to keep there? just compile test. Link: http://lkml.kernel.org/r/50949FC9.6050202@gmail.com Signed-off-by: Shan Wei Signed-off-by: Steven Rostedt --- include/trace/ftrace.h | 73 -------------------------------------------------- 1 file changed, 73 deletions(-) (limited to 'include/trace') diff --git a/include/trace/ftrace.h b/include/trace/ftrace.h index 698f2a890322..40dc5e8fe340 100644 --- a/include/trace/ftrace.h +++ b/include/trace/ftrace.h @@ -619,79 +619,6 @@ __attribute__((section("_ftrace_events"))) *__event_##call = &event_##call #include TRACE_INCLUDE(TRACE_INCLUDE_FILE) -/* - * Define the insertion callback to perf events - * - * The job is very similar to ftrace_raw_event_ except that we don't - * insert in the ring buffer but in a perf counter. - * - * static void ftrace_perf_(proto) - * { - * struct ftrace_data_offsets_ __maybe_unused __data_offsets; - * struct ftrace_event_call *event_call = &event_; - * extern void perf_tp_event(int, u64, u64, void *, int); - * struct ftrace_raw_##call *entry; - * struct perf_trace_buf *trace_buf; - * u64 __addr = 0, __count = 1; - * unsigned long irq_flags; - * struct trace_entry *ent; - * int __entry_size; - * int __data_size; - * int __cpu - * int pc; - * - * pc = preempt_count(); - * - * __data_size = ftrace_get_offsets_(&__data_offsets, args); - * - * // Below we want to get the aligned size by taking into account - * // the u32 field that will later store the buffer size - * __entry_size = ALIGN(__data_size + sizeof(*entry) + sizeof(u32), - * sizeof(u64)); - * __entry_size -= sizeof(u32); - * - * // Protect the non nmi buffer - * // This also protects the rcu read side - * local_irq_save(irq_flags); - * __cpu = smp_processor_id(); - * - * if (in_nmi()) - * trace_buf = rcu_dereference_sched(perf_trace_buf_nmi); - * else - * trace_buf = rcu_dereference_sched(perf_trace_buf); - * - * if (!trace_buf) - * goto end; - * - * trace_buf = per_cpu_ptr(trace_buf, __cpu); - * - * // Avoid recursion from perf that could mess up the buffer - * if (trace_buf->recursion++) - * goto end_recursion; - * - * raw_data = trace_buf->buf; - * - * // Make recursion update visible before entering perf_tp_event - * // so that we protect from perf recursions. - * - * barrier(); - * - * //zero dead bytes from alignment to avoid stack leak to userspace: - * *(u64 *)(&raw_data[__entry_size - sizeof(u64)]) = 0ULL; - * entry = (struct ftrace_raw_ *)raw_data; - * ent = &entry->ent; - * tracing_generic_entry_update(ent, irq_flags, pc); - * ent->type = event_call->id; - * - * <- do some jobs with dynamic arrays - * - * <- affect our values - * - * perf_tp_event(event_call->id, __addr, __count, entry, - * __entry_size); <- submit them to perf counter - * - * } - */ #ifdef CONFIG_PERF_EVENTS -- cgit v1.2.3-59-g8ed1b