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-rw-r--r--include/linux/ring_buffer.h3
-rw-r--r--kernel/profile.c2
-rw-r--r--kernel/trace/ftrace.c34
-rw-r--r--kernel/trace/ring_buffer.c115
4 files changed, 135 insertions, 19 deletions
diff --git a/include/linux/ring_buffer.h b/include/linux/ring_buffer.h
index 536b0ca46a03..e097c2e6b6dc 100644
--- a/include/linux/ring_buffer.h
+++ b/include/linux/ring_buffer.h
@@ -120,6 +120,9 @@ unsigned long ring_buffer_overruns(struct ring_buffer *buffer);
u64 ring_buffer_time_stamp(int cpu);
void ring_buffer_normalize_time_stamp(int cpu, u64 *ts);
+void tracing_on(void);
+void tracing_off(void);
+
enum ring_buffer_flags {
RB_FL_OVERWRITE = 1 << 0,
};
diff --git a/kernel/profile.c b/kernel/profile.c
index 9830a037d8db..5b7d1ac7124c 100644
--- a/kernel/profile.c
+++ b/kernel/profile.c
@@ -544,7 +544,7 @@ static const struct file_operations proc_profile_operations = {
};
#ifdef CONFIG_SMP
-static void __init profile_nop(void *unused)
+static inline void profile_nop(void *unused)
{
}
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c
index 4a39d24568c8..e60205722d0c 100644
--- a/kernel/trace/ftrace.c
+++ b/kernel/trace/ftrace.c
@@ -185,7 +185,6 @@ enum {
};
static int ftrace_filtered;
-static int tracing_on;
static LIST_HEAD(ftrace_new_addrs);
@@ -506,13 +505,10 @@ static int __ftrace_modify_code(void *data)
{
int *command = data;
- if (*command & FTRACE_ENABLE_CALLS) {
+ if (*command & FTRACE_ENABLE_CALLS)
ftrace_replace_code(1);
- tracing_on = 1;
- } else if (*command & FTRACE_DISABLE_CALLS) {
+ else if (*command & FTRACE_DISABLE_CALLS)
ftrace_replace_code(0);
- tracing_on = 0;
- }
if (*command & FTRACE_UPDATE_TRACE_FUNC)
ftrace_update_ftrace_func(ftrace_trace_function);
@@ -677,7 +673,7 @@ static int __init ftrace_dyn_table_alloc(unsigned long num_to_init)
cnt = num_to_init / ENTRIES_PER_PAGE;
pr_info("ftrace: allocating %ld entries in %d pages\n",
- num_to_init, cnt);
+ num_to_init, cnt + 1);
for (i = 0; i < cnt; i++) {
pg->next = (void *)get_zeroed_page(GFP_KERNEL);
@@ -757,13 +753,11 @@ static void *t_start(struct seq_file *m, loff_t *pos)
void *p = NULL;
loff_t l = -1;
- if (*pos != iter->pos) {
- for (p = t_next(m, p, &l); p && l < *pos; p = t_next(m, p, &l))
- ;
- } else {
- l = *pos;
- p = t_next(m, p, &l);
- }
+ if (*pos > iter->pos)
+ *pos = iter->pos;
+
+ l = *pos;
+ p = t_next(m, p, &l);
return p;
}
@@ -774,15 +768,21 @@ static void t_stop(struct seq_file *m, void *p)
static int t_show(struct seq_file *m, void *v)
{
+ struct ftrace_iterator *iter = m->private;
struct dyn_ftrace *rec = v;
char str[KSYM_SYMBOL_LEN];
+ int ret = 0;
if (!rec)
return 0;
kallsyms_lookup(rec->ip, NULL, NULL, NULL, str);
- seq_printf(m, "%s\n", str);
+ ret = seq_printf(m, "%s\n", str);
+ if (ret < 0) {
+ iter->pos--;
+ iter->idx--;
+ }
return 0;
}
@@ -808,7 +808,7 @@ ftrace_avail_open(struct inode *inode, struct file *file)
return -ENOMEM;
iter->pg = ftrace_pages_start;
- iter->pos = -1;
+ iter->pos = 0;
ret = seq_open(file, &show_ftrace_seq_ops);
if (!ret) {
@@ -895,7 +895,7 @@ ftrace_regex_open(struct inode *inode, struct file *file, int enable)
if (file->f_mode & FMODE_READ) {
iter->pg = ftrace_pages_start;
- iter->pos = -1;
+ iter->pos = 0;
iter->flags = enable ? FTRACE_ITER_FILTER :
FTRACE_ITER_NOTRACE;
diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c
index 2f76193c3489..036456cbb4f7 100644
--- a/kernel/trace/ring_buffer.c
+++ b/kernel/trace/ring_buffer.c
@@ -16,14 +16,49 @@
#include <linux/list.h>
#include <linux/fs.h>
+#include "trace.h"
+
+/* Global flag to disable all recording to ring buffers */
+static int ring_buffers_off __read_mostly;
+
+/**
+ * tracing_on - enable all tracing buffers
+ *
+ * This function enables all tracing buffers that may have been
+ * disabled with tracing_off.
+ */
+void tracing_on(void)
+{
+ ring_buffers_off = 0;
+}
+
+/**
+ * tracing_off - turn off all tracing buffers
+ *
+ * This function stops all tracing buffers from recording data.
+ * It does not disable any overhead the tracers themselves may
+ * be causing. This function simply causes all recording to
+ * the ring buffers to fail.
+ */
+void tracing_off(void)
+{
+ ring_buffers_off = 1;
+}
+
/* Up this if you want to test the TIME_EXTENTS and normalization */
#define DEBUG_SHIFT 0
/* FIXME!!! */
u64 ring_buffer_time_stamp(int cpu)
{
+ u64 time;
+
+ preempt_disable_notrace();
/* shift to debug/test normalization and TIME_EXTENTS */
- return sched_clock() << DEBUG_SHIFT;
+ time = sched_clock() << DEBUG_SHIFT;
+ preempt_enable_notrace();
+
+ return time;
}
void ring_buffer_normalize_time_stamp(int cpu, u64 *ts)
@@ -503,6 +538,12 @@ int ring_buffer_resize(struct ring_buffer *buffer, unsigned long size)
LIST_HEAD(pages);
int i, cpu;
+ /*
+ * Always succeed at resizing a non-existent buffer:
+ */
+ if (!buffer)
+ return size;
+
size = DIV_ROUND_UP(size, BUF_PAGE_SIZE);
size *= BUF_PAGE_SIZE;
buffer_size = buffer->pages * BUF_PAGE_SIZE;
@@ -1133,6 +1174,9 @@ ring_buffer_lock_reserve(struct ring_buffer *buffer,
struct ring_buffer_event *event;
int cpu, resched;
+ if (ring_buffers_off)
+ return NULL;
+
if (atomic_read(&buffer->record_disabled))
return NULL;
@@ -1249,6 +1293,9 @@ int ring_buffer_write(struct ring_buffer *buffer,
int ret = -EBUSY;
int cpu, resched;
+ if (ring_buffers_off)
+ return -EBUSY;
+
if (atomic_read(&buffer->record_disabled))
return -EBUSY;
@@ -2070,3 +2117,69 @@ int ring_buffer_swap_cpu(struct ring_buffer *buffer_a,
return 0;
}
+static ssize_t
+rb_simple_read(struct file *filp, char __user *ubuf,
+ size_t cnt, loff_t *ppos)
+{
+ int *p = filp->private_data;
+ char buf[64];
+ int r;
+
+ /* !ring_buffers_off == tracing_on */
+ r = sprintf(buf, "%d\n", !*p);
+
+ return simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
+}
+
+static ssize_t
+rb_simple_write(struct file *filp, const char __user *ubuf,
+ size_t cnt, loff_t *ppos)
+{
+ int *p = filp->private_data;
+ char buf[64];
+ long val;
+ int ret;
+
+ if (cnt >= sizeof(buf))
+ return -EINVAL;
+
+ if (copy_from_user(&buf, ubuf, cnt))
+ return -EFAULT;
+
+ buf[cnt] = 0;
+
+ ret = strict_strtoul(buf, 10, &val);
+ if (ret < 0)
+ return ret;
+
+ /* !ring_buffers_off == tracing_on */
+ *p = !val;
+
+ (*ppos)++;
+
+ return cnt;
+}
+
+static struct file_operations rb_simple_fops = {
+ .open = tracing_open_generic,
+ .read = rb_simple_read,
+ .write = rb_simple_write,
+};
+
+
+static __init int rb_init_debugfs(void)
+{
+ struct dentry *d_tracer;
+ struct dentry *entry;
+
+ d_tracer = tracing_init_dentry();
+
+ entry = debugfs_create_file("tracing_on", 0644, d_tracer,
+ &ring_buffers_off, &rb_simple_fops);
+ if (!entry)
+ pr_warning("Could not create debugfs 'tracing_on' entry\n");
+
+ return 0;
+}
+
+fs_initcall(rb_init_debugfs);