diff options
| -rw-r--r-- | kernel/trace/trace.c | 168 | ||||
| -rw-r--r-- | kernel/trace/trace.h | 3 |
2 files changed, 147 insertions, 24 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 11ba100f9a9..aa58b7bc847 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -98,6 +98,9 @@ static inline void ftrace_enable_cpu(void) static cpumask_var_t __read_mostly tracing_buffer_mask; +/* Define which cpu buffers are currently read in trace_pipe */ +static cpumask_var_t tracing_reader_cpumask; + #define for_each_tracing_cpu(cpu) \ for_each_cpu(cpu, tracing_buffer_mask) @@ -1195,10 +1198,25 @@ __find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts) { struct ring_buffer *buffer = iter->tr->buffer; struct trace_entry *ent, *next = NULL; + int cpu_file = iter->cpu_file; u64 next_ts = 0, ts; int next_cpu = -1; int cpu; + /* + * If we are in a per_cpu trace file, don't bother by iterating over + * all cpu and peek directly. + */ + if (cpu_file > TRACE_PIPE_ALL_CPU) { + if (ring_buffer_empty_cpu(buffer, cpu_file)) + return NULL; + ent = peek_next_entry(iter, cpu_file, ent_ts); + if (ent_cpu) + *ent_cpu = cpu_file; + + return ent; + } + for_each_tracing_cpu(cpu) { if (ring_buffer_empty_cpu(buffer, cpu)) @@ -1279,6 +1297,7 @@ static void *s_next(struct seq_file *m, void *v, loff_t *pos) static void *s_start(struct seq_file *m, loff_t *pos) { struct trace_iterator *iter = m->private; + int cpu_file = iter->cpu_file; void *p = NULL; loff_t l = 0; int cpu; @@ -1299,9 +1318,12 @@ static void *s_start(struct seq_file *m, loff_t *pos) ftrace_disable_cpu(); - for_each_tracing_cpu(cpu) { - ring_buffer_iter_reset(iter->buffer_iter[cpu]); - } + if (cpu_file == TRACE_PIPE_ALL_CPU) { + for_each_tracing_cpu(cpu) + ring_buffer_iter_reset(iter->buffer_iter[cpu]); + } else + ring_buffer_iter_reset(iter->buffer_iter[cpu_file]); + ftrace_enable_cpu(); @@ -1653,6 +1675,7 @@ static struct seq_operations tracer_seq_ops = { static struct trace_iterator * __tracing_open(struct inode *inode, struct file *file, int *ret) { + long cpu_file = (long) inode->i_private; struct trace_iterator *iter; struct seq_file *m; int cpu; @@ -1672,9 +1695,10 @@ __tracing_open(struct inode *inode, struct file *file, int *ret) if (current_trace && current_trace->print_max) iter->tr = &max_tr; else - iter->tr = inode->i_private; + iter->tr = &global_trace; iter->trace = current_trace; iter->pos = -1; + iter->cpu_file = cpu_file; /* Notify the tracer early; before we stop tracing. */ if (iter->trace && iter->trace->open) @@ -1684,14 +1708,22 @@ __tracing_open(struct inode *inode, struct file *file, int *ret) if (ring_buffer_overruns(iter->tr->buffer)) iter->iter_flags |= TRACE_FILE_ANNOTATE; + if (iter->cpu_file == TRACE_PIPE_ALL_CPU) { + for_each_tracing_cpu(cpu) { - for_each_tracing_cpu(cpu) { + iter->buffer_iter[cpu] = + ring_buffer_read_start(iter->tr->buffer, cpu); + if (!iter->buffer_iter[cpu]) + goto fail_buffer; + } + } else { + cpu = iter->cpu_file; iter->buffer_iter[cpu] = - ring_buffer_read_start(iter->tr->buffer, cpu); + ring_buffer_read_start(iter->tr->buffer, cpu); if (!iter->buffer_iter[cpu]) - goto fail_buffer; + goto fail; } /* TODO stop tracer */ @@ -1715,6 +1747,7 @@ __tracing_open(struct inode *inode, struct file *file, int *ret) if (iter->buffer_iter[cpu]) ring_buffer_read_finish(iter->buffer_iter[cpu]); } +fail: mutex_unlock(&trace_types_lock); kfree(iter); @@ -2325,54 +2358,77 @@ tracing_max_lat_write(struct file *filp, const char __user *ubuf, return cnt; } -static atomic_t tracing_reader; - static int tracing_open_pipe(struct inode *inode, struct file *filp) { + long cpu_file = (long) inode->i_private; struct trace_iterator *iter; + int ret = 0; if (tracing_disabled) return -ENODEV; - /* We only allow for reader of the pipe */ - if (atomic_inc_return(&tracing_reader) != 1) { - atomic_dec(&tracing_reader); - return -EBUSY; + mutex_lock(&trace_types_lock); + + /* We only allow one reader per cpu */ + if (cpu_file == TRACE_PIPE_ALL_CPU) { + if (!cpumask_empty(tracing_reader_cpumask)) { + ret = -EBUSY; + goto out; + } + cpumask_setall(tracing_reader_cpumask); + } else { + if (!cpumask_test_cpu(cpu_file, tracing_reader_cpumask)) + cpumask_set_cpu(cpu_file, tracing_reader_cpumask); + else { + ret = -EBUSY; + goto out; + } } /* create a buffer to store the information to pass to userspace */ iter = kzalloc(sizeof(*iter), GFP_KERNEL); - if (!iter) - return -ENOMEM; + if (!iter) { + ret = -ENOMEM; + goto out; + } if (!alloc_cpumask_var(&iter->started, GFP_KERNEL)) { kfree(iter); - return -ENOMEM; + ret = -ENOMEM; + goto out; } - mutex_lock(&trace_types_lock); - /* trace pipe does not show start of buffer */ cpumask_setall(iter->started); + iter->cpu_file = cpu_file; iter->tr = &global_trace; iter->trace = current_trace; filp->private_data = iter; if (iter->trace->pipe_open) iter->trace->pipe_open(iter); - mutex_unlock(&trace_types_lock); - return 0; +out: + mutex_unlock(&trace_types_lock); + return ret; } static int tracing_release_pipe(struct inode *inode, struct file *file) { struct trace_iterator *iter = file->private_data; + mutex_lock(&trace_types_lock); + + if (iter->cpu_file == TRACE_PIPE_ALL_CPU) + cpumask_clear(tracing_reader_cpumask); + else + cpumask_clear_cpu(iter->cpu_file, tracing_reader_cpumask); + + mutex_unlock(&trace_types_lock); + free_cpumask_var(iter->started); kfree(iter); - atomic_dec(&tracing_reader); return 0; } @@ -2911,6 +2967,59 @@ struct dentry *tracing_init_dentry(void) return d_tracer; } +static struct dentry *d_percpu; + +struct dentry *tracing_dentry_percpu(void) +{ + static int once; + struct dentry *d_tracer; + + if (d_percpu) + return d_percpu; + + d_tracer = tracing_init_dentry(); + + if (!d_tracer) + return NULL; + + d_percpu = debugfs_create_dir("per_cpu", d_tracer); + + if (!d_percpu && !once) { + once = 1; + pr_warning("Could not create debugfs directory 'per_cpu'\n"); + return NULL; + } + + return d_percpu; +} + +static void tracing_init_debugfs_percpu(long cpu) +{ + struct dentry *d_percpu = tracing_dentry_percpu(); + struct dentry *entry; + /* strlen(trace_pipe) + MAX(log10(cpu)) + '\0' */ + char filename[17]; + + if (cpu > 999 || cpu < 0) + return; + + /* per cpu trace_pipe */ + sprintf(filename, "trace_pipe%ld", cpu); + + entry = debugfs_create_file(filename, 0444, d_percpu, + (void *) cpu, &tracing_pipe_fops); + if (!entry) + pr_warning("Could not create debugfs '%s' entry\n", filename); + + /* per cpu trace */ + sprintf(filename, "trace%ld", cpu); + + entry = debugfs_create_file(filename, 0444, d_percpu, + (void *) cpu, &tracing_fops); + if (!entry) + pr_warning("Could not create debugfs '%s' entry\n", filename); +} + #ifdef CONFIG_FTRACE_SELFTEST /* Let selftest have access to static functions in this file */ #include "trace_selftest.c" @@ -2920,6 +3029,7 @@ static __init int tracer_init_debugfs(void) { struct dentry *d_tracer; struct dentry *entry; + int cpu; d_tracer = tracing_init_dentry(); @@ -2939,7 +3049,7 @@ static __init int tracer_init_debugfs(void) pr_warning("Could not create debugfs 'tracing_cpumask' entry\n"); entry = debugfs_create_file("trace", 0444, d_tracer, - &global_trace, &tracing_fops); + (void *) TRACE_PIPE_ALL_CPU, &tracing_fops); if (!entry) pr_warning("Could not create debugfs 'trace' entry\n"); @@ -2970,8 +3080,8 @@ static __init int tracer_init_debugfs(void) if (!entry) pr_warning("Could not create debugfs 'README' entry\n"); - entry = debugfs_create_file("trace_pipe", 0644, d_tracer, - NULL, &tracing_pipe_fops); + entry = debugfs_create_file("trace_pipe", 0444, d_tracer, + (void *) TRACE_PIPE_ALL_CPU, &tracing_pipe_fops); if (!entry) pr_warning("Could not create debugfs " "'trace_pipe' entry\n"); @@ -2999,6 +3109,10 @@ static __init int tracer_init_debugfs(void) #ifdef CONFIG_SYSPROF_TRACER init_tracer_sysprof_debugfs(d_tracer); #endif + + for_each_tracing_cpu(cpu) + tracing_init_debugfs_percpu(cpu); + return 0; } @@ -3222,8 +3336,12 @@ __init static int tracer_alloc_buffers(void) if (!alloc_cpumask_var(&tracing_cpumask, GFP_KERNEL)) goto out_free_buffer_mask; + if (!alloc_cpumask_var(&tracing_reader_cpumask, GFP_KERNEL)) + goto out_free_tracing_cpumask; + cpumask_copy(tracing_buffer_mask, cpu_possible_mask); cpumask_copy(tracing_cpumask, cpu_all_mask); + cpumask_clear(tracing_reader_cpumask); /* TODO: make the number of buffers hot pluggable with CPUS */ global_trace.buffer = ring_buffer_alloc(trace_buf_size, @@ -3272,6 +3390,8 @@ __init static int tracer_alloc_buffers(void) ret = 0; out_free_cpumask: + free_cpumask_var(tracing_reader_cpumask); +out_free_tracing_cpumask: free_cpumask_var(tracing_cpumask); out_free_buffer_mask: free_cpumask_var(tracing_buffer_mask); diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index eed732c151f..508235a39da 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -395,6 +395,8 @@ struct trace_seq { unsigned int readpos; }; +#define TRACE_PIPE_ALL_CPU -1 + /* * Trace iterator - used by printout routines who present trace * results to users and which routines might sleep, etc: @@ -404,6 +406,7 @@ struct trace_iterator { struct tracer *trace; void *private; struct ring_buffer_iter *buffer_iter[NR_CPUS]; + int cpu_file; /* The below is zeroed out in pipe_read */ struct trace_seq seq; |