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author | Steven Rostedt (Red Hat) <srostedt@redhat.com> | 2013-03-07 22:48:09 -0500 |
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committer | Steven Rostedt <rostedt@goodmis.org> | 2013-03-15 00:35:53 -0400 |
commit | 55034cd6e648155393b0d665eef76b38d49ad6bf (patch) | |
tree | 3d51bc6a1f8c7bdf7f728113b3853f4c20441be9 /kernel | |
parent | f4e781c0a89d5810729772290441ac7d61f321ec (diff) | |
download | linux-stable-55034cd6e648155393b0d665eef76b38d49ad6bf.tar.gz linux-stable-55034cd6e648155393b0d665eef76b38d49ad6bf.tar.bz2 linux-stable-55034cd6e648155393b0d665eef76b38d49ad6bf.zip |
tracing: Add alloc_snapshot kernel command line parameter
If debugging the kernel, and the developer wants to use
tracing_snapshot() in places where tracing_snapshot_alloc() may
be difficult (or more likely, the developer is lazy and doesn't
want to bother with tracing_snapshot_alloc() at all), then adding
alloc_snapshot
to the kernel command line parameter will tell ftrace to allocate
the snapshot buffer (if configured) when it allocates the main
tracing buffer.
I also noticed that ring_buffer_expanded and tracing_selftest_disabled
had inconsistent use of boolean "true" and "false" with "0" and "1".
I cleaned that up too.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/trace/trace.c | 81 | ||||
-rw-r--r-- | kernel/trace/trace.h | 2 | ||||
-rw-r--r-- | kernel/trace/trace_events.c | 4 |
3 files changed, 51 insertions, 36 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 57b4220d96a9..4021a5e66412 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -47,7 +47,7 @@ * On boot up, the ring buffer is set to the minimum size, so that * we do not waste memory on systems that are not using tracing. */ -int ring_buffer_expanded; +bool ring_buffer_expanded; /* * We need to change this state when a selftest is running. @@ -121,12 +121,14 @@ static int tracing_set_tracer(const char *buf); static char bootup_tracer_buf[MAX_TRACER_SIZE] __initdata; static char *default_bootup_tracer; +static bool allocate_snapshot; + static int __init set_cmdline_ftrace(char *str) { strncpy(bootup_tracer_buf, str, MAX_TRACER_SIZE); default_bootup_tracer = bootup_tracer_buf; /* We are using ftrace early, expand it */ - ring_buffer_expanded = 1; + ring_buffer_expanded = true; return 1; } __setup("ftrace=", set_cmdline_ftrace); @@ -147,6 +149,15 @@ static int __init set_ftrace_dump_on_oops(char *str) } __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops); +static int __init alloc_snapshot(char *str) +{ + allocate_snapshot = true; + /* We also need the main ring buffer expanded */ + ring_buffer_expanded = true; + return 1; +} +__setup("alloc_snapshot", alloc_snapshot); + static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata; static char *trace_boot_options __initdata; @@ -951,7 +962,7 @@ int register_tracer(struct tracer *type) tracing_set_tracer(type->name); default_bootup_tracer = NULL; /* disable other selftests, since this will break it. */ - tracing_selftest_disabled = 1; + tracing_selftest_disabled = true; #ifdef CONFIG_FTRACE_STARTUP_TEST printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n", type->name); @@ -3318,7 +3329,7 @@ static int __tracing_resize_ring_buffer(struct trace_array *tr, * we use the size that was given, and we can forget about * expanding it later. */ - ring_buffer_expanded = 1; + ring_buffer_expanded = true; /* May be called before buffers are initialized */ if (!tr->trace_buffer.buffer) @@ -5396,53 +5407,57 @@ static void init_trace_buffers(struct trace_array *tr, struct trace_buffer *buf) } } -static int allocate_trace_buffers(struct trace_array *tr, int size) +static int +allocate_trace_buffer(struct trace_array *tr, struct trace_buffer *buf, int size) { enum ring_buffer_flags rb_flags; rb_flags = trace_flags & TRACE_ITER_OVERWRITE ? RB_FL_OVERWRITE : 0; - tr->trace_buffer.buffer = ring_buffer_alloc(size, rb_flags); - if (!tr->trace_buffer.buffer) - goto out_free; + buf->buffer = ring_buffer_alloc(size, rb_flags); + if (!buf->buffer) + return -ENOMEM; - tr->trace_buffer.data = alloc_percpu(struct trace_array_cpu); - if (!tr->trace_buffer.data) - goto out_free; + buf->data = alloc_percpu(struct trace_array_cpu); + if (!buf->data) { + ring_buffer_free(buf->buffer); + return -ENOMEM; + } - init_trace_buffers(tr, &tr->trace_buffer); + init_trace_buffers(tr, buf); /* Allocate the first page for all buffers */ set_buffer_entries(&tr->trace_buffer, ring_buffer_size(tr->trace_buffer.buffer, 0)); -#ifdef CONFIG_TRACER_MAX_TRACE - - tr->max_buffer.buffer = ring_buffer_alloc(1, rb_flags); - if (!tr->max_buffer.buffer) - goto out_free; - - tr->max_buffer.data = alloc_percpu(struct trace_array_cpu); - if (!tr->max_buffer.data) - goto out_free; + return 0; +} - init_trace_buffers(tr, &tr->max_buffer); +static int allocate_trace_buffers(struct trace_array *tr, int size) +{ + int ret; - set_buffer_entries(&tr->max_buffer, 1); -#endif - return 0; + ret = allocate_trace_buffer(tr, &tr->trace_buffer, size); + if (ret) + return ret; - out_free: - if (tr->trace_buffer.buffer) +#ifdef CONFIG_TRACER_MAX_TRACE + ret = allocate_trace_buffer(tr, &tr->max_buffer, + allocate_snapshot ? size : 1); + if (WARN_ON(ret)) { ring_buffer_free(tr->trace_buffer.buffer); - free_percpu(tr->trace_buffer.data); + free_percpu(tr->trace_buffer.data); + return -ENOMEM; + } + tr->allocated_snapshot = allocate_snapshot; -#ifdef CONFIG_TRACER_MAX_TRACE - if (tr->max_buffer.buffer) - ring_buffer_free(tr->max_buffer.buffer); - free_percpu(tr->max_buffer.data); + /* + * Only the top level trace array gets its snapshot allocated + * from the kernel command line. + */ + allocate_snapshot = false; #endif - return -ENOMEM; + return 0; } static int new_instance_create(const char *name) diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index f4931821a966..26bc71834041 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -660,7 +660,7 @@ extern int DYN_FTRACE_TEST_NAME(void); #define DYN_FTRACE_TEST_NAME2 trace_selftest_dynamic_test_func2 extern int DYN_FTRACE_TEST_NAME2(void); -extern int ring_buffer_expanded; +extern bool ring_buffer_expanded; extern bool tracing_selftest_disabled; DECLARE_PER_CPU(int, ftrace_cpu_disabled); diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c index a376ab5eec5c..38b54c5edeb9 100644 --- a/kernel/trace/trace_events.c +++ b/kernel/trace/trace_events.c @@ -1844,8 +1844,8 @@ static char bootup_event_buf[COMMAND_LINE_SIZE] __initdata; static __init int setup_trace_event(char *str) { strlcpy(bootup_event_buf, str, COMMAND_LINE_SIZE); - ring_buffer_expanded = 1; - tracing_selftest_disabled = 1; + ring_buffer_expanded = true; + tracing_selftest_disabled = true; return 1; } |