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yaml
---
r: 140849
b: refs/heads/master
c: 2cadf91
h: refs/heads/master
i:
  140847: adc9016
v: v3
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Steven Rostedt committed Mar 4, 2009
1 parent 7ee5aab commit 54fdf9c
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Showing 3 changed files with 269 additions and 8 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 474d32b68d6d842f3e710e9ae9fe2568c53339f8
refs/heads/master: 2cadf9135eb3b6d84b6427314be827ddd443c308
274 changes: 267 additions & 7 deletions trunk/kernel/trace/trace.c
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Original file line number Diff line number Diff line change
Expand Up @@ -11,31 +11,30 @@
* Copyright (C) 2004-2006 Ingo Molnar
* Copyright (C) 2004 William Lee Irwin III
*/
#include <linux/ring_buffer.h>
#include <linux/utsrelease.h>
#include <linux/stacktrace.h>
#include <linux/writeback.h>
#include <linux/kallsyms.h>
#include <linux/seq_file.h>
#include <linux/notifier.h>
#include <linux/irqflags.h>
#include <linux/debugfs.h>
#include <linux/pagemap.h>
#include <linux/hardirq.h>
#include <linux/linkage.h>
#include <linux/uaccess.h>
#include <linux/kprobes.h>
#include <linux/ftrace.h>
#include <linux/module.h>
#include <linux/percpu.h>
#include <linux/splice.h>
#include <linux/kdebug.h>
#include <linux/ctype.h>
#include <linux/init.h>
#include <linux/poll.h>
#include <linux/gfp.h>
#include <linux/fs.h>
#include <linux/kprobes.h>
#include <linux/writeback.h>
#include <linux/splice.h>

#include <linux/stacktrace.h>
#include <linux/ring_buffer.h>
#include <linux/irqflags.h>

#include "trace.h"
#include "trace_output.h"
Expand Down Expand Up @@ -3005,6 +3004,246 @@ static struct file_operations tracing_mark_fops = {
.write = tracing_mark_write,
};

struct ftrace_buffer_info {
struct trace_array *tr;
void *spare;
int cpu;
unsigned int read;
};

static int tracing_buffers_open(struct inode *inode, struct file *filp)
{
int cpu = (int)(long)inode->i_private;
struct ftrace_buffer_info *info;

if (tracing_disabled)
return -ENODEV;

info = kzalloc(sizeof(*info), GFP_KERNEL);
if (!info)
return -ENOMEM;

info->tr = &global_trace;
info->cpu = cpu;
info->spare = ring_buffer_alloc_read_page(info->tr->buffer);
/* Force reading ring buffer for first read */
info->read = (unsigned int)-1;
if (!info->spare)
goto out;

filp->private_data = info;

return 0;

out:
kfree(info);
return -ENOMEM;
}

static ssize_t
tracing_buffers_read(struct file *filp, char __user *ubuf,
size_t count, loff_t *ppos)
{
struct ftrace_buffer_info *info = filp->private_data;
unsigned int pos;
ssize_t ret;
size_t size;

/* Do we have previous read data to read? */
if (info->read < PAGE_SIZE)
goto read;

info->read = 0;

ret = ring_buffer_read_page(info->tr->buffer,
&info->spare,
count,
info->cpu, 0);
if (ret < 0)
return 0;

pos = ring_buffer_page_len(info->spare);

if (pos < PAGE_SIZE)
memset(info->spare + pos, 0, PAGE_SIZE - pos);

read:
size = PAGE_SIZE - info->read;
if (size > count)
size = count;

ret = copy_to_user(ubuf, info->spare + info->read, size);
if (ret)
return -EFAULT;
*ppos += size;
info->read += size;

return size;
}

static int tracing_buffers_release(struct inode *inode, struct file *file)
{
struct ftrace_buffer_info *info = file->private_data;

ring_buffer_free_read_page(info->tr->buffer, info->spare);
kfree(info);

return 0;
}

struct buffer_ref {
struct ring_buffer *buffer;
void *page;
int ref;
};

static void buffer_pipe_buf_release(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
struct buffer_ref *ref = (struct buffer_ref *)buf->private;

if (--ref->ref)
return;

ring_buffer_free_read_page(ref->buffer, ref->page);
kfree(ref);
buf->private = 0;
}

static int buffer_pipe_buf_steal(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
return 1;
}

static void buffer_pipe_buf_get(struct pipe_inode_info *pipe,
struct pipe_buffer *buf)
{
struct buffer_ref *ref = (struct buffer_ref *)buf->private;

ref->ref++;
}

/* Pipe buffer operations for a buffer. */
static struct pipe_buf_operations buffer_pipe_buf_ops = {
.can_merge = 0,
.map = generic_pipe_buf_map,
.unmap = generic_pipe_buf_unmap,
.confirm = generic_pipe_buf_confirm,
.release = buffer_pipe_buf_release,
.steal = buffer_pipe_buf_steal,
.get = buffer_pipe_buf_get,
};

/*
* Callback from splice_to_pipe(), if we need to release some pages
* at the end of the spd in case we error'ed out in filling the pipe.
*/
static void buffer_spd_release(struct splice_pipe_desc *spd, unsigned int i)
{
struct buffer_ref *ref =
(struct buffer_ref *)spd->partial[i].private;

if (--ref->ref)
return;

ring_buffer_free_read_page(ref->buffer, ref->page);
kfree(ref);
spd->partial[i].private = 0;
}

static ssize_t
tracing_buffers_splice_read(struct file *file, loff_t *ppos,
struct pipe_inode_info *pipe, size_t len,
unsigned int flags)
{
struct ftrace_buffer_info *info = file->private_data;
struct partial_page partial[PIPE_BUFFERS];
struct page *pages[PIPE_BUFFERS];
struct splice_pipe_desc spd = {
.pages = pages,
.partial = partial,
.flags = flags,
.ops = &buffer_pipe_buf_ops,
.spd_release = buffer_spd_release,
};
struct buffer_ref *ref;
int size, i;
size_t ret;

/*
* We can't seek on a buffer input
*/
if (unlikely(*ppos))
return -ESPIPE;


for (i = 0; i < PIPE_BUFFERS && len; i++, len -= size) {
struct page *page;
int r;

ref = kzalloc(sizeof(*ref), GFP_KERNEL);
if (!ref)
break;

ref->buffer = info->tr->buffer;
ref->page = ring_buffer_alloc_read_page(ref->buffer);
if (!ref->page) {
kfree(ref);
break;
}

r = ring_buffer_read_page(ref->buffer, &ref->page,
len, info->cpu, 0);
if (r < 0) {
ring_buffer_free_read_page(ref->buffer,
ref->page);
kfree(ref);
break;
}

/*
* zero out any left over data, this is going to
* user land.
*/
size = ring_buffer_page_len(ref->page);
if (size < PAGE_SIZE)
memset(ref->page + size, 0, PAGE_SIZE - size);

page = virt_to_page(ref->page);

spd.pages[i] = page;
spd.partial[i].len = PAGE_SIZE;
spd.partial[i].offset = 0;
spd.partial[i].private = (unsigned long)ref;
spd.nr_pages++;
}

spd.nr_pages = i;

/* did we read anything? */
if (!spd.nr_pages) {
if (flags & SPLICE_F_NONBLOCK)
ret = -EAGAIN;
else
ret = 0;
/* TODO: block */
return ret;
}

ret = splice_to_pipe(pipe, &spd);

return ret;
}

static const struct file_operations tracing_buffers_fops = {
.open = tracing_buffers_open,
.read = tracing_buffers_read,
.release = tracing_buffers_release,
.splice_read = tracing_buffers_splice_read,
.llseek = no_llseek,
};

#ifdef CONFIG_DYNAMIC_FTRACE

int __weak ftrace_arch_read_dyn_info(char *buf, int size)
Expand Down Expand Up @@ -3399,6 +3638,7 @@ static __init void create_trace_options_dir(void)
static __init int tracer_init_debugfs(void)
{
struct dentry *d_tracer;
struct dentry *buffers;
struct dentry *entry;
int cpu;

Expand Down Expand Up @@ -3471,6 +3711,26 @@ static __init int tracer_init_debugfs(void)
pr_warning("Could not create debugfs "
"'trace_marker' entry\n");

buffers = debugfs_create_dir("binary_buffers", d_tracer);

if (!buffers)
pr_warning("Could not create buffers directory\n");
else {
int cpu;
char buf[64];

for_each_tracing_cpu(cpu) {
sprintf(buf, "%d", cpu);

entry = debugfs_create_file(buf, 0444, buffers,
(void *)(long)cpu,
&tracing_buffers_fops);
if (!entry)
pr_warning("Could not create debugfs buffers "
"'%s' entry\n", buf);
}
}

#ifdef CONFIG_DYNAMIC_FTRACE
entry = debugfs_create_file("dyn_ftrace_total_info", 0444, d_tracer,
&ftrace_update_tot_cnt,
Expand Down
1 change: 1 addition & 0 deletions trunk/kernel/trace/trace.h
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Original file line number Diff line number Diff line change
Expand Up @@ -217,6 +217,7 @@ enum trace_flag_type {
*/
struct trace_array_cpu {
atomic_t disabled;
void *buffer_page; /* ring buffer spare */

/* these fields get copied into max-trace: */
unsigned long trace_idx;
Expand Down

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