From b02ee9a33b65bcc4ad13c12a0b04afdaab3ddd8d Mon Sep 17 00:00:00 2001 From: Minho Ban Date: Mon, 7 May 2012 11:36:00 +0900 Subject: tracing: Prevent wasting time evaluating parameters in trace_preempt_on/off This fixes spending time for evaluating parameters in trace_preempt_on/off when the tracer config is off. The patch mainly inspired by Steven Rostedt, thanks Steven. Link: http://lkml.kernel.org/r/4FA73510.7070705@samsung.com Cc: Ingo Molnar Cc: Frederic Weisbecker Cc: Peter Zijlstra Cc: Paul Turner Cc: Thomas Gleixner Cc: Hidetoshi Seto Cc: Paul E. McKenney Cc: Josh Triplett Signed-off-by: Minho Ban Signed-off-by: Steven Rostedt --- include/linux/ftrace.h | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h index 0b5590330bca..d32cc5e4b0cc 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -491,8 +491,12 @@ static inline void __ftrace_enabled_restore(int enabled) extern void trace_preempt_on(unsigned long a0, unsigned long a1); extern void trace_preempt_off(unsigned long a0, unsigned long a1); #else - static inline void trace_preempt_on(unsigned long a0, unsigned long a1) { } - static inline void trace_preempt_off(unsigned long a0, unsigned long a1) { } +/* + * Use defines instead of static inlines because some arches will make code out + * of the CALLER_ADDR, when we really want these to be a real nop. + */ +# define trace_preempt_on(a0, a1) do { } while (0) +# define trace_preempt_off(a0, a1) do { } while (0) #endif #ifdef CONFIG_FTRACE_MCOUNT_RECORD -- cgit v1.2.3-58-ga151 From 50e18b94c695644d824381e7574b9c44acc25ffe Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Wed, 25 Apr 2012 10:23:39 +0200 Subject: tracing: Use seq_*_private interface for some seq files It's appropriate to use __seq_open_private interface to open some of trace seq files, because it covers all steps we are duplicating in tracing code - zallocating the iterator and setting it as seq_file's private. Using this for following files: trace available_filter_functions enabled_functions Link: http://lkml.kernel.org/r/1335342219-2782-5-git-send-email-jolsa@redhat.com Signed-off-by: Jiri Olsa [ Fixed warnings for: kernel/trace/trace.c: In function '__tracing_open': kernel/trace/trace.c:2418:11: warning: unused variable 'ret' [-Wunused-variable] kernel/trace/trace.c:2417:19: warning: unused variable 'm' [-Wunused-variable] ] Signed-off-by: Steven Rostedt --- kernel/trace/ftrace.c | 44 +++++++++++--------------------------------- kernel/trace/trace.c | 30 +++++------------------------- 2 files changed, 16 insertions(+), 58 deletions(-) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 0fa92f677c92..cf81f27ce6c6 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2469,57 +2469,35 @@ static int ftrace_avail_open(struct inode *inode, struct file *file) { struct ftrace_iterator *iter; - int ret; if (unlikely(ftrace_disabled)) return -ENODEV; - iter = kzalloc(sizeof(*iter), GFP_KERNEL); - if (!iter) - return -ENOMEM; - - iter->pg = ftrace_pages_start; - iter->ops = &global_ops; - - ret = seq_open(file, &show_ftrace_seq_ops); - if (!ret) { - struct seq_file *m = file->private_data; - - m->private = iter; - } else { - kfree(iter); + iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter)); + if (iter) { + iter->pg = ftrace_pages_start; + iter->ops = &global_ops; } - return ret; + return iter ? 0 : -ENOMEM; } static int ftrace_enabled_open(struct inode *inode, struct file *file) { struct ftrace_iterator *iter; - int ret; if (unlikely(ftrace_disabled)) return -ENODEV; - iter = kzalloc(sizeof(*iter), GFP_KERNEL); - if (!iter) - return -ENOMEM; - - iter->pg = ftrace_pages_start; - iter->flags = FTRACE_ITER_ENABLED; - iter->ops = &global_ops; - - ret = seq_open(file, &show_ftrace_seq_ops); - if (!ret) { - struct seq_file *m = file->private_data; - - m->private = iter; - } else { - kfree(iter); + iter = __seq_open_private(file, &show_ftrace_seq_ops, sizeof(*iter)); + if (iter) { + iter->pg = ftrace_pages_start; + iter->flags = FTRACE_ITER_ENABLED; + iter->ops = &global_ops; } - return ret; + return iter ? 0 : -ENOMEM; } static void ftrace_filter_reset(struct ftrace_hash *hash) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index f11a285ee5bb..4fb10ef727d3 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2413,15 +2413,13 @@ static struct trace_iterator * __tracing_open(struct inode *inode, struct file *file) { long cpu_file = (long) inode->i_private; - void *fail_ret = ERR_PTR(-ENOMEM); struct trace_iterator *iter; - struct seq_file *m; - int cpu, ret; + int cpu; if (tracing_disabled) return ERR_PTR(-ENODEV); - iter = kzalloc(sizeof(*iter), GFP_KERNEL); + iter = __seq_open_private(file, &tracer_seq_ops, sizeof(*iter)); if (!iter) return ERR_PTR(-ENOMEM); @@ -2478,32 +2476,15 @@ __tracing_open(struct inode *inode, struct file *file) tracing_iter_reset(iter, cpu); } - ret = seq_open(file, &tracer_seq_ops); - if (ret < 0) { - fail_ret = ERR_PTR(ret); - goto fail_buffer; - } - - m = file->private_data; - m->private = iter; - mutex_unlock(&trace_types_lock); return iter; - fail_buffer: - for_each_tracing_cpu(cpu) { - if (iter->buffer_iter[cpu]) - ring_buffer_read_finish(iter->buffer_iter[cpu]); - } - free_cpumask_var(iter->started); - tracing_start(); fail: mutex_unlock(&trace_types_lock); kfree(iter->trace); - kfree(iter); - - return fail_ret; + seq_release_private(inode, file); + return ERR_PTR(-ENOMEM); } int tracing_open_generic(struct inode *inode, struct file *filp) @@ -2539,11 +2520,10 @@ static int tracing_release(struct inode *inode, struct file *file) tracing_start(); mutex_unlock(&trace_types_lock); - seq_release(inode, file); mutex_destroy(&iter->mutex); free_cpumask_var(iter->started); kfree(iter->trace); - kfree(iter); + seq_release_private(inode, file); return 0; } -- cgit v1.2.3-58-ga151 From 68179686ac67cb08f08b1ef28b860d5ed899f242 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Tue, 8 May 2012 20:57:53 -0400 Subject: tracing: Remove ftrace_disable/enable_cpu() The ftrace_disable_cpu() and ftrace_enable_cpu() functions were needed back before the ring buffer was lockless. Now that the ring buffer is lockless (and has been for some time), these functions serve no purpose, and unnecessarily slow down operations of the tracer. Signed-off-by: Steven Rostedt --- kernel/trace/trace.c | 44 ++------------------------------------------ 1 file changed, 2 insertions(+), 42 deletions(-) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 4fb10ef727d3..48ef4960ec90 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -87,18 +87,6 @@ static int tracing_disabled = 1; DEFINE_PER_CPU(int, ftrace_cpu_disabled); -static inline void ftrace_disable_cpu(void) -{ - preempt_disable(); - __this_cpu_inc(ftrace_cpu_disabled); -} - -static inline void ftrace_enable_cpu(void) -{ - __this_cpu_dec(ftrace_cpu_disabled); - preempt_enable(); -} - cpumask_var_t __read_mostly tracing_buffer_mask; /* @@ -748,8 +736,6 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) arch_spin_lock(&ftrace_max_lock); - ftrace_disable_cpu(); - ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu); if (ret == -EBUSY) { @@ -763,8 +749,6 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) "Failed to swap buffers due to commit in progress\n"); } - ftrace_enable_cpu(); - WARN_ON_ONCE(ret && ret != -EAGAIN && ret != -EBUSY); __update_max_tr(tr, tsk, cpu); @@ -916,13 +900,6 @@ out: mutex_unlock(&trace_types_lock); } -static void __tracing_reset(struct ring_buffer *buffer, int cpu) -{ - ftrace_disable_cpu(); - ring_buffer_reset_cpu(buffer, cpu); - ftrace_enable_cpu(); -} - void tracing_reset(struct trace_array *tr, int cpu) { struct ring_buffer *buffer = tr->buffer; @@ -931,7 +908,7 @@ void tracing_reset(struct trace_array *tr, int cpu) /* Make sure all commits have finished */ synchronize_sched(); - __tracing_reset(buffer, cpu); + ring_buffer_reset_cpu(buffer, cpu); ring_buffer_record_enable(buffer); } @@ -949,7 +926,7 @@ void tracing_reset_online_cpus(struct trace_array *tr) tr->time_start = ftrace_now(tr->cpu); for_each_online_cpu(cpu) - __tracing_reset(buffer, cpu); + ring_buffer_reset_cpu(buffer, cpu); ring_buffer_record_enable(buffer); } @@ -1733,14 +1710,9 @@ EXPORT_SYMBOL_GPL(trace_vprintk); static void trace_iterator_increment(struct trace_iterator *iter) { - /* Don't allow ftrace to trace into the ring buffers */ - ftrace_disable_cpu(); - iter->idx++; if (iter->buffer_iter[iter->cpu]) ring_buffer_read(iter->buffer_iter[iter->cpu], NULL); - - ftrace_enable_cpu(); } static struct trace_entry * @@ -1750,17 +1722,12 @@ peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts, struct ring_buffer_event *event; struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu]; - /* Don't allow ftrace to trace into the ring buffers */ - ftrace_disable_cpu(); - if (buf_iter) event = ring_buffer_iter_peek(buf_iter, ts); else event = ring_buffer_peek(iter->tr->buffer, cpu, ts, lost_events); - ftrace_enable_cpu(); - if (event) { iter->ent_size = ring_buffer_event_length(event); return ring_buffer_event_data(event); @@ -1850,11 +1817,8 @@ void *trace_find_next_entry_inc(struct trace_iterator *iter) static void trace_consume(struct trace_iterator *iter) { - /* Don't allow ftrace to trace into the ring buffers */ - ftrace_disable_cpu(); ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts, &iter->lost_events); - ftrace_enable_cpu(); } static void *s_next(struct seq_file *m, void *v, loff_t *pos) @@ -1943,16 +1907,12 @@ static void *s_start(struct seq_file *m, loff_t *pos) iter->cpu = 0; iter->idx = -1; - ftrace_disable_cpu(); - if (cpu_file == TRACE_PIPE_ALL_CPU) { for_each_tracing_cpu(cpu) tracing_iter_reset(iter, cpu); } else tracing_iter_reset(iter, cpu_file); - ftrace_enable_cpu(); - iter->leftover = 0; for (p = iter; p && l < *pos; p = s_next(m, p, &l)) ; -- cgit v1.2.3-58-ga151