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author | Steven Rostedt (Red Hat) <rostedt@goodmis.org> | 2013-03-12 11:49:18 -0400 |
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committer | Steven Rostedt <rostedt@goodmis.org> | 2013-03-15 00:36:01 -0400 |
commit | 77fd5c15e3216b901be69047ca43b05ae9099951 (patch) | |
tree | 1790b9bacd1d371cf03902efaf99cdc9d08abdec /kernel | |
parent | 3209cff4490bee55fd2bc1d087cb8ecf2a686a88 (diff) | |
download | linux-stable-77fd5c15e3216b901be69047ca43b05ae9099951.tar.gz linux-stable-77fd5c15e3216b901be69047ca43b05ae9099951.tar.bz2 linux-stable-77fd5c15e3216b901be69047ca43b05ae9099951.zip |
tracing: Add snapshot trigger to function probes
echo 'schedule:snapshot:1' > /debug/tracing/set_ftrace_filter
This will cause the scheduler to trigger a snapshot the next time
it's called (you can use any function that's not called by NMI).
Even though it triggers only once, you still need to remove it with:
echo '!schedule:snapshot:0' > /debug/tracing/set_ftrace_filter
The :1 can be left off for the first command:
echo 'schedule:snapshot' > /debug/tracing/set_ftrace_filter
But this will cause all calls to schedule to trigger a snapshot.
This must be removed without the ':0'
echo '!schedule:snapshot' > /debug/tracing/set_ftrace_filter
As adding a "count" is a different operation (internally).
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/trace/trace.c | 111 |
1 files changed, 110 insertions, 1 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 906049c0af90..c5b844621562 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -5086,7 +5086,114 @@ static const struct file_operations tracing_dyn_info_fops = { .read = tracing_read_dyn_info, .llseek = generic_file_llseek, }; -#endif +#endif /* CONFIG_DYNAMIC_FTRACE */ + +#if defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) +static void +ftrace_snapshot(unsigned long ip, unsigned long parent_ip, void **data) +{ + tracing_snapshot(); +} + +static void +ftrace_count_snapshot(unsigned long ip, unsigned long parent_ip, void **data) +{ + unsigned long *count = (long *)data; + + if (!*count) + return; + + if (*count != -1) + (*count)--; + + tracing_snapshot(); +} + +static int +ftrace_snapshot_print(struct seq_file *m, unsigned long ip, + struct ftrace_probe_ops *ops, void *data) +{ + long count = (long)data; + + seq_printf(m, "%ps:", (void *)ip); + + seq_printf(m, "snapshot"); + + if (count == -1) + seq_printf(m, ":unlimited\n"); + else + seq_printf(m, ":count=%ld\n", count); + + return 0; +} + +static struct ftrace_probe_ops snapshot_probe_ops = { + .func = ftrace_snapshot, + .print = ftrace_snapshot_print, +}; + +static struct ftrace_probe_ops snapshot_count_probe_ops = { + .func = ftrace_count_snapshot, + .print = ftrace_snapshot_print, +}; + +static int +ftrace_trace_snapshot_callback(struct ftrace_hash *hash, + char *glob, char *cmd, char *param, int enable) +{ + struct ftrace_probe_ops *ops; + void *count = (void *)-1; + char *number; + int ret; + + /* hash funcs only work with set_ftrace_filter */ + if (!enable) + return -EINVAL; + + ops = param ? &snapshot_count_probe_ops : &snapshot_probe_ops; + + if (glob[0] == '!') { + unregister_ftrace_function_probe_func(glob+1, ops); + return 0; + } + + if (!param) + goto out_reg; + + number = strsep(¶m, ":"); + + if (!strlen(number)) + goto out_reg; + + /* + * We use the callback data field (which is a pointer) + * as our counter. + */ + ret = kstrtoul(number, 0, (unsigned long *)&count); + if (ret) + return ret; + + out_reg: + ret = register_ftrace_function_probe(glob, ops, count); + + if (ret >= 0) + alloc_snapshot(&global_trace); + + return ret < 0 ? ret : 0; +} + +static struct ftrace_func_command ftrace_snapshot_cmd = { + .name = "snapshot", + .func = ftrace_trace_snapshot_callback, +}; + +static int register_snapshot_cmd(void) +{ + return register_ftrace_command(&ftrace_snapshot_cmd); +} +#else +static inline int register_snapshot_cmd(void) { return 0; } +#endif /* defined(CONFIG_TRACER_SNAPSHOT) && defined(CONFIG_DYNAMIC_FTRACE) */ struct dentry *tracing_init_dentry_tr(struct trace_array *tr) { @@ -6076,6 +6183,8 @@ __init static int tracer_alloc_buffers(void) trace_set_options(&global_trace, option); } + register_snapshot_cmd(); + return 0; out_free_cpumask: |