diff options
| -rw-r--r-- | kernel/trace/trace.c | 66 |
1 files changed, 56 insertions, 10 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index a08c127..3039326 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -2436,6 +2436,31 @@ static void test_ftrace_alive(struct seq_file *m) } #ifdef CONFIG_TRACER_MAX_TRACE +static void show_snapshot_main_help(struct seq_file *m) +{ + seq_printf(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"); + seq_printf(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"); + seq_printf(m, "# Takes a snapshot of the main buffer.\n"); + seq_printf(m, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)\n"); + seq_printf(m, "# (Doesn't have to be '2' works with any number that\n"); + seq_printf(m, "# is not a '0' or '1')\n"); +} + +static void show_snapshot_percpu_help(struct seq_file *m) +{ + seq_printf(m, "# echo 0 > snapshot : Invalid for per_cpu snapshot file.\n"); +#ifdef CONFIG_RING_BUFFER_ALLOW_SWAP + seq_printf(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"); + seq_printf(m, "# Takes a snapshot of the main buffer for this cpu.\n"); +#else + seq_printf(m, "# echo 1 > snapshot : Not supported with this kernel.\n"); + seq_printf(m, "# Must use main snapshot file to allocate.\n"); +#endif + seq_printf(m, "# echo 2 > snapshot : Clears this cpu's snapshot buffer (but does not allocate)\n"); + seq_printf(m, "# (Doesn't have to be '2' works with any number that\n"); + seq_printf(m, "# is not a '0' or '1')\n"); +} + static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) { if (iter->trace->allocated_snapshot) @@ -2444,12 +2469,10 @@ static void print_snapshot_help(struct seq_file *m, struct trace_iterator *iter) seq_printf(m, "#\n# * Snapshot is freed *\n#\n"); seq_printf(m, "# Snapshot commands:\n"); - seq_printf(m, "# echo 0 > snapshot : Clears and frees snapshot buffer\n"); - seq_printf(m, "# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.\n"); - seq_printf(m, "# Takes a snapshot of the main buffer.\n"); - seq_printf(m, "# echo 2 > snapshot : Clears snapshot buffer (but does not allocate)\n"); - seq_printf(m, "# (Doesn't have to be '2' works with any number that\n"); - seq_printf(m, "# is not a '0' or '1')\n"); + if (iter->cpu_file == RING_BUFFER_ALL_CPUS) + show_snapshot_main_help(m); + else + show_snapshot_percpu_help(m); } #else /* Should never be called */ @@ -4207,6 +4230,7 @@ static int tracing_snapshot_open(struct inode *inode, struct file *file) } iter->tr = tc->tr; iter->trace_buffer = &tc->tr->max_buffer; + iter->cpu_file = tc->cpu; m->private = iter; file->private_data = m; } @@ -4241,6 +4265,10 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt, switch (val) { case 0: + if (iter->cpu_file != RING_BUFFER_ALL_CPUS) { + ret = -EINVAL; + break; + } if (tr->current_trace->allocated_snapshot) { /* free spare buffer */ ring_buffer_resize(tr->max_buffer.buffer, 1, @@ -4251,6 +4279,13 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt, } break; case 1: +/* Only allow per-cpu swap if the ring buffer supports it */ +#ifndef CONFIG_RING_BUFFER_ALLOW_SWAP + if (iter->cpu_file != RING_BUFFER_ALL_CPUS) { + ret = -EINVAL; + break; + } +#endif if (!tr->current_trace->allocated_snapshot) { /* allocate spare buffer */ ret = resize_buffer_duplicate_size(&tr->max_buffer, @@ -4259,15 +4294,21 @@ tracing_snapshot_write(struct file *filp, const char __user *ubuf, size_t cnt, break; tr->current_trace->allocated_snapshot = true; } - local_irq_disable(); /* Now, we're going to swap */ - update_max_tr(&global_trace, current, smp_processor_id()); + if (iter->cpu_file == RING_BUFFER_ALL_CPUS) + update_max_tr(&global_trace, current, smp_processor_id()); + else + update_max_tr_single(&global_trace, current, iter->cpu_file); local_irq_enable(); break; default: - if (tr->current_trace->allocated_snapshot) - tracing_reset_online_cpus(&tr->max_buffer); + if (tr->current_trace->allocated_snapshot) { + if (iter->cpu_file == RING_BUFFER_ALL_CPUS) + tracing_reset_online_cpus(&tr->max_buffer); + else + tracing_reset(&tr->max_buffer, iter->cpu_file); + } break; } @@ -4835,6 +4876,11 @@ tracing_init_debugfs_percpu(struct trace_array *tr, long cpu) trace_create_file("buffer_size_kb", 0444, d_cpu, (void *)&data->trace_cpu, &tracing_entries_fops); + +#ifdef CONFIG_TRACER_SNAPSHOT + trace_create_file("snapshot", 0644, d_cpu, + (void *)&data->trace_cpu, &snapshot_fops); +#endif } #ifdef CONFIG_FTRACE_SELFTEST |