summaryrefslogtreecommitdiff
path: root/kernel/trace/trace_printk.c
diff options
context:
space:
mode:
authorFrederic Weisbecker <fweisbec@gmail.com>2009-03-06 17:21:49 +0100
committerIngo Molnar <mingo@elte.hu>2009-03-06 17:59:12 +0100
commit769b0441f438c4bb4872cb8560eb6fe51bcc09ee (patch)
tree9908682dfd89e97c3097a7c3adcae35d821e1895 /kernel/trace/trace_printk.c
parent1ba28e02a18cbdbea123836f6c98efb09cbf59ec (diff)
downloadlinux-next-769b0441f438c4bb4872cb8560eb6fe51bcc09ee.tar.gz
tracing/core: drop the old trace_printk() implementation in favour of trace_bprintk()
Impact: faster and lighter tracing Now that we have trace_bprintk() which is faster and consume lesser memory than trace_printk() and has the same purpose, we can now drop the old implementation in favour of the binary one from trace_bprintk(), which means we move all the implementation of trace_bprintk() to trace_printk(), so the Api doesn't change except that we must now use trace_seq_bprintk() to print the TRACE_PRINT entries. Some changes result of this: - Previously, trace_bprintk depended of a single tracer and couldn't work without. This tracer has been dropped and the whole implementation of trace_printk() (like the module formats management) is now integrated in the tracing core (comes with CONFIG_TRACING), though we keep the file trace_printk (previously trace_bprintk.c) where we can find the module management. Thus we don't overflow trace.c - changes some parts to use trace_seq_bprintk() to print TRACE_PRINT entries. - change a bit trace_printk/trace_vprintk macros to support non-builtin formats constants, and fix 'const' qualifiers warnings. But this is all transparent for developers. - etc... V2: - Rebase against last changes - Fix mispell on the changelog V3: - Rebase against last changes (moving trace_printk() to kernel.h) Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Acked-by: Steven Rostedt <rostedt@goodmis.org> LKML-Reference: <1236356510-8381-5-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/trace/trace_printk.c')
-rw-r--r--kernel/trace/trace_printk.c138
1 files changed, 138 insertions, 0 deletions
diff --git a/kernel/trace/trace_printk.c b/kernel/trace/trace_printk.c
new file mode 100644
index 000000000000..a50aea22e929
--- /dev/null
+++ b/kernel/trace/trace_printk.c
@@ -0,0 +1,138 @@
+/*
+ * trace binary printk
+ *
+ * Copyright (C) 2008 Lai Jiangshan <laijs@cn.fujitsu.com>
+ *
+ */
+#include <linux/kernel.h>
+#include <linux/ftrace.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/seq_file.h>
+#include <linux/fs.h>
+#include <linux/marker.h>
+#include <linux/uaccess.h>
+
+#include "trace.h"
+
+#ifdef CONFIG_MODULES
+
+/*
+ * modules trace_printk()'s formats are autosaved in struct trace_bprintk_fmt
+ * which are queued on trace_bprintk_fmt_list.
+ */
+static LIST_HEAD(trace_bprintk_fmt_list);
+
+/* serialize accesses to trace_bprintk_fmt_list */
+static DEFINE_MUTEX(btrace_mutex);
+
+struct trace_bprintk_fmt {
+ struct list_head list;
+ char fmt[0];
+};
+
+static inline struct trace_bprintk_fmt *lookup_format(const char *fmt)
+{
+ struct trace_bprintk_fmt *pos;
+ list_for_each_entry(pos, &trace_bprintk_fmt_list, list) {
+ if (!strcmp(pos->fmt, fmt))
+ return pos;
+ }
+ return NULL;
+}
+
+static
+void hold_module_trace_bprintk_format(const char **start, const char **end)
+{
+ const char **iter;
+
+ mutex_lock(&btrace_mutex);
+ for (iter = start; iter < end; iter++) {
+ struct trace_bprintk_fmt *tb_fmt = lookup_format(*iter);
+ if (tb_fmt) {
+ *iter = tb_fmt->fmt;
+ continue;
+ }
+
+ tb_fmt = kmalloc(offsetof(struct trace_bprintk_fmt, fmt)
+ + strlen(*iter) + 1, GFP_KERNEL);
+ if (tb_fmt) {
+ list_add_tail(&tb_fmt->list, &trace_bprintk_fmt_list);
+ strcpy(tb_fmt->fmt, *iter);
+ *iter = tb_fmt->fmt;
+ } else
+ *iter = NULL;
+ }
+ mutex_unlock(&btrace_mutex);
+}
+
+static int module_trace_bprintk_format_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ struct module *mod = data;
+ if (mod->num_trace_bprintk_fmt) {
+ const char **start = mod->trace_bprintk_fmt_start;
+ const char **end = start + mod->num_trace_bprintk_fmt;
+
+ if (val == MODULE_STATE_COMING)
+ hold_module_trace_bprintk_format(start, end);
+ }
+ return 0;
+}
+
+#else /* !CONFIG_MODULES */
+__init static int
+module_trace_bprintk_format_notify(struct notifier_block *self,
+ unsigned long val, void *data)
+{
+ return 0;
+}
+#endif /* CONFIG_MODULES */
+
+
+__initdata_or_module static
+struct notifier_block module_trace_bprintk_format_nb = {
+ .notifier_call = module_trace_bprintk_format_notify,
+};
+
+int __trace_printk(unsigned long ip, const char *fmt, ...)
+ {
+ int ret;
+ va_list ap;
+
+ if (unlikely(!fmt))
+ return 0;
+
+ if (!(trace_flags & TRACE_ITER_PRINTK))
+ return 0;
+
+ va_start(ap, fmt);
+ ret = trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
+ va_end(ap);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(__trace_printk);
+
+int __ftrace_vprintk(unsigned long ip, const char *fmt, va_list ap)
+ {
+ if (unlikely(!fmt))
+ return 0;
+
+ if (!(trace_flags & TRACE_ITER_PRINTK))
+ return 0;
+
+ return trace_vprintk(ip, task_curr_ret_stack(current), fmt, ap);
+}
+EXPORT_SYMBOL_GPL(__ftrace_vprintk);
+
+
+static __init int init_trace_printk(void)
+{
+ return register_module_notifier(&module_trace_bprintk_format_nb);
+}
+
+early_initcall(init_trace_printk);