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Date: Thu, 12 Feb 2009 17:23:54 -0200
From: Arnaldo Carvalho de Melo <acme@...hat.com>
To: Steven Rostedt <rostedt@...dmis.org>
Cc: Ingo Molnar <mingo@...e.hu>,
Frédéric Weisbecker <fweisbec@...il.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: [PATCH tip 1/1] tracing: Only drop the BKL in register_tracer if
there is a selftest
Impact: cleanup
We only need to drop the BKL for some tracers, and then only if the
tracer being registered has a selftest method. So clean up moving the
selftest bits to a different function.
Cc: Ingo Molnar <mingo@...e.hu>
Cc: Frédéric Weisbecker <fweisbec@...il.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
kernel/trace/trace.c | 138 ++++++++++++++++++++++++++++----------------------
1 files changed, 77 insertions(+), 61 deletions(-)
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 95f99a7..fc01e0c 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -452,6 +452,76 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu)
__raw_spin_unlock(&ftrace_max_lock);
}
+static int trace_selftest(struct tracer *trace)
+{
+ int ret = 0;
+#ifdef CONFIG_FTRACE_STARTUP_TEST
+ struct tracer *saved_tracer;
+ struct trace_array *tr;
+ int i;
+
+ if (trace->selftest == NULL || tracing_selftest_disabled)
+ return 0;
+ /*
+ * When this gets called we hold the BKL which means that
+ * preemption is disabled. Various trace selftests however
+ * need to disable and enable preemption for successful tests.
+ * So we drop the BKL here and grab it after the tests again.
+ */
+ unlock_kernel();
+
+ saved_tracer = current_trace;
+ tr = &global_trace;
+
+ /*
+ * Run a selftest on this tracer.
+ * Here we reset the trace buffer, and set the current
+ * tracer to be this tracer. The tracer can then run some
+ * internal tracing to verify that everything is in order.
+ * If we fail, we do not register this tracer.
+ */
+ for_each_tracing_cpu(i)
+ tracing_reset(tr, i);
+
+ current_trace = trace;
+ /* the test is responsible for initializing and enabling */
+ pr_info("Testing tracer %s: ", trace->name);
+ ret = trace->selftest(trace, tr);
+ /* the test is responsible for resetting too */
+ current_trace = saved_tracer;
+ if (ret)
+ printk(KERN_CONT "FAILED!\n");
+ else {
+ /* Only reset on passing, to avoid touching corrupted buffers */
+ for_each_tracing_cpu(i)
+ tracing_reset(tr, i);
+
+ printk(KERN_CONT "PASSED\n");
+ }
+
+ tracing_selftest_running = false;
+ lock_kernel();
+#endif
+ return ret;
+}
+
+static void trace_boot(struct tracer *trace)
+{
+ if (strncmp(default_bootup_tracer, trace->name, BOOTUP_TRACER_SIZE))
+ return;
+
+ pr_info("Starting tracer '%s'\n", trace->name);
+ /* Do we want this tracer to start on bootup? */
+ tracing_set_tracer(trace->name);
+ default_bootup_tracer = NULL;
+ /* disable other selftests, since this will break it. */
+ tracing_selftest_disabled = 1;
+#ifdef CONFIG_FTRACE_STARTUP_TEST
+ pr_info("Disabling FTRACE selftests due to running tracer '%s'\n",
+ trace->name);
+#endif
+}
+
/**
* register_tracer - register a tracer with the ftrace system.
* @type - the plugin for the tracer
@@ -471,13 +541,6 @@ __acquires(kernel_lock)
return -1;
}
- /*
- * When this gets called we hold the BKL which means that
- * preemption is disabled. Various trace selftests however
- * need to disable and enable preemption for successful tests.
- * So we drop the BKL here and grab it after the tests again.
- */
- unlock_kernel();
mutex_lock(&trace_types_lock);
tracing_selftest_running = true;
@@ -488,7 +551,7 @@ __acquires(kernel_lock)
pr_info("Trace %s already registered\n",
type->name);
ret = -1;
- goto out;
+ goto out_mutex_unlock;
}
}
@@ -500,39 +563,9 @@ __acquires(kernel_lock)
if (!type->flags->opts)
type->flags->opts = dummy_tracer_opt;
-#ifdef CONFIG_FTRACE_STARTUP_TEST
- if (type->selftest && !tracing_selftest_disabled) {
- struct tracer *saved_tracer = current_trace;
- struct trace_array *tr = &global_trace;
- int i;
-
- /*
- * Run a selftest on this tracer.
- * Here we reset the trace buffer, and set the current
- * tracer to be this tracer. The tracer can then run some
- * internal tracing to verify that everything is in order.
- * If we fail, we do not register this tracer.
- */
- for_each_tracing_cpu(i)
- tracing_reset(tr, i);
-
- current_trace = type;
- /* the test is responsible for initializing and enabling */
- pr_info("Testing tracer %s: ", type->name);
- ret = type->selftest(type, tr);
- /* the test is responsible for resetting too */
- current_trace = saved_tracer;
- if (ret) {
- printk(KERN_CONT "FAILED!\n");
- goto out;
- }
- /* Only reset on passing, to avoid touching corrupted buffers */
- for_each_tracing_cpu(i)
- tracing_reset(tr, i);
-
- printk(KERN_CONT "PASSED\n");
- }
-#endif
+ ret = trace_selftest(type);
+ if (ret != 0)
+ goto out_mutex_unlock;
type->next = trace_types;
trace_types = type;
@@ -540,29 +573,12 @@ __acquires(kernel_lock)
if (len > max_tracer_type_len)
max_tracer_type_len = len;
- out:
- tracing_selftest_running = false;
+out_mutex_unlock:
mutex_unlock(&trace_types_lock);
- if (ret || !default_bootup_tracer)
- goto out_unlock;
-
- if (strncmp(default_bootup_tracer, type->name, BOOTUP_TRACER_SIZE))
- goto out_unlock;
-
- printk(KERN_INFO "Starting tracer '%s'\n", type->name);
- /* Do we want this tracer to start on bootup? */
- tracing_set_tracer(type->name);
- default_bootup_tracer = NULL;
- /* disable other selftests, since this will break it. */
- tracing_selftest_disabled = 1;
-#ifdef CONFIG_FTRACE_STARTUP_TEST
- printk(KERN_INFO "Disabling FTRACE selftests due to running tracer '%s'\n",
- type->name);
-#endif
+ if (ret == 0 && default_bootup_tracer)
+ trace_boot(type);
- out_unlock:
- lock_kernel();
return ret;
}
--
1.6.0.6
--
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