Commit 2602c3ba authored by Ingo Molnar's avatar Ingo Molnar

Merge branch 'rfc/splice/tip/tracing/ftrace' of...

Merge branch 'rfc/splice/tip/tracing/ftrace' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace into tracing/ftrace
parents a1be621d 2cadf913
......@@ -121,6 +121,9 @@ unsigned long ring_buffer_overrun_cpu(struct ring_buffer *buffer, int cpu);
u64 ring_buffer_time_stamp(int cpu);
void ring_buffer_normalize_time_stamp(int cpu, u64 *ts);
size_t ring_buffer_page_len(void *page);
/*
* The below functions are fine to use outside the tracing facility.
*/
......@@ -138,8 +141,8 @@ static inline int tracing_is_on(void) { return 0; }
void *ring_buffer_alloc_read_page(struct ring_buffer *buffer);
void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data);
int ring_buffer_read_page(struct ring_buffer *buffer,
void **data_page, int cpu, int full);
int ring_buffer_read_page(struct ring_buffer *buffer, void **data_page,
size_t len, int cpu, int full);
enum ring_buffer_flags {
RB_FL_OVERWRITE = 1 << 0,
......
......@@ -61,6 +61,8 @@ enum {
static unsigned long ring_buffer_flags __read_mostly = RB_BUFFERS_ON;
#define BUF_PAGE_HDR_SIZE offsetof(struct buffer_data_page, data)
/**
* tracing_on - enable all tracing buffers
*
......@@ -132,7 +134,7 @@ void ring_buffer_normalize_time_stamp(int cpu, u64 *ts)
}
EXPORT_SYMBOL_GPL(ring_buffer_normalize_time_stamp);
#define RB_EVNT_HDR_SIZE (sizeof(struct ring_buffer_event))
#define RB_EVNT_HDR_SIZE (offsetof(struct ring_buffer_event, array))
#define RB_ALIGNMENT 4U
#define RB_MAX_SMALL_DATA 28
......@@ -234,6 +236,18 @@ static void rb_init_page(struct buffer_data_page *bpage)
local_set(&bpage->commit, 0);
}
/**
* ring_buffer_page_len - the size of data on the page.
* @page: The page to read
*
* Returns the amount of data on the page, including buffer page header.
*/
size_t ring_buffer_page_len(void *page)
{
return local_read(&((struct buffer_data_page *)page)->commit)
+ BUF_PAGE_HDR_SIZE;
}
/*
* Also stolen from mm/slob.c. Thanks to Mathieu Desnoyers for pointing
* this issue out.
......@@ -254,7 +268,7 @@ static inline int test_time_stamp(u64 delta)
return 0;
}
#define BUF_PAGE_SIZE (PAGE_SIZE - offsetof(struct buffer_data_page, data))
#define BUF_PAGE_SIZE (PAGE_SIZE - BUF_PAGE_HDR_SIZE)
/*
* head_page == tail_page && head == tail then buffer is empty.
......@@ -2378,8 +2392,8 @@ static void rb_remove_entries(struct ring_buffer_per_cpu *cpu_buffer,
*/
void *ring_buffer_alloc_read_page(struct ring_buffer *buffer)
{
unsigned long addr;
struct buffer_data_page *bpage;
unsigned long addr;
addr = __get_free_page(GFP_KERNEL);
if (!addr)
......@@ -2387,6 +2401,8 @@ void *ring_buffer_alloc_read_page(struct ring_buffer *buffer)
bpage = (void *)addr;
rb_init_page(bpage);
return bpage;
}
......@@ -2406,6 +2422,7 @@ void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data)
* ring_buffer_read_page - extract a page from the ring buffer
* @buffer: buffer to extract from
* @data_page: the page to use allocated from ring_buffer_alloc_read_page
* @len: amount to extract
* @cpu: the cpu of the buffer to extract
* @full: should the extraction only happen when the page is full.
*
......@@ -2418,7 +2435,7 @@ void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data)
* rpage = ring_buffer_alloc_read_page(buffer);
* if (!rpage)
* return error;
* ret = ring_buffer_read_page(buffer, &rpage, cpu, 0);
* ret = ring_buffer_read_page(buffer, &rpage, len, cpu, 0);
* if (ret >= 0)
* process_page(rpage, ret);
*
......@@ -2435,70 +2452,103 @@ void ring_buffer_free_read_page(struct ring_buffer *buffer, void *data)
* <0 if no data has been transferred.
*/
int ring_buffer_read_page(struct ring_buffer *buffer,
void **data_page, int cpu, int full)
void **data_page, size_t len, int cpu, int full)
{
struct ring_buffer_per_cpu *cpu_buffer = buffer->buffers[cpu];
struct ring_buffer_event *event;
struct buffer_data_page *bpage;
struct buffer_page *reader;
unsigned long flags;
unsigned int commit;
unsigned int read;
int ret = -1;
/*
* If len is not big enough to hold the page header, then
* we can not copy anything.
*/
if (len <= BUF_PAGE_HDR_SIZE)
return -1;
len -= BUF_PAGE_HDR_SIZE;
if (!data_page)
return 0;
return -1;
bpage = *data_page;
if (!bpage)
return 0;
return -1;
spin_lock_irqsave(&cpu_buffer->reader_lock, flags);
/*
* rb_buffer_peek will get the next ring buffer if
* the current reader page is empty.
*/
event = rb_buffer_peek(buffer, cpu, NULL);
if (!event)
reader = rb_get_reader_page(cpu_buffer);
if (!reader)
goto out;
/* check for data */
if (!local_read(&cpu_buffer->reader_page->page->commit))
goto out;
event = rb_reader_event(cpu_buffer);
read = reader->read;
commit = rb_page_commit(reader);
read = cpu_buffer->reader_page->read;
/*
* If the writer is already off of the read page, then simply
* switch the read page with the given page. Otherwise
* we need to copy the data from the reader to the writer.
* If this page has been partially read or
* if len is not big enough to read the rest of the page or
* a writer is still on the page, then
* we must copy the data from the page to the buffer.
* Otherwise, we can simply swap the page with the one passed in.
*/
if (cpu_buffer->reader_page == cpu_buffer->commit_page) {
unsigned int commit = rb_page_commit(cpu_buffer->reader_page);
if (read || (len < (commit - read)) ||
cpu_buffer->reader_page == cpu_buffer->commit_page) {
struct buffer_data_page *rpage = cpu_buffer->reader_page->page;
unsigned int rpos = read;
unsigned int pos = 0;
unsigned int size;
if (full)
goto out;
/* The writer is still on the reader page, we must copy */
memcpy(bpage->data + read, rpage->data + read, commit - read);
/* consume what was read */
cpu_buffer->reader_page->read = commit;
if (len > (commit - read))
len = (commit - read);
size = rb_event_length(event);
if (len < size)
goto out;
/* Need to copy one event at a time */
do {
memcpy(bpage->data + pos, rpage->data + rpos, size);
len -= size;
rb_advance_reader(cpu_buffer);
rpos = reader->read;
pos += size;
event = rb_reader_event(cpu_buffer);
size = rb_event_length(event);
} while (len > size);
/* update bpage */
local_set(&bpage->commit, commit);
if (!read)
bpage->time_stamp = rpage->time_stamp;
local_set(&bpage->commit, pos);
bpage->time_stamp = rpage->time_stamp;
/* we copied everything to the beginning */
read = 0;
} else {
/* swap the pages */
rb_init_page(bpage);
bpage = cpu_buffer->reader_page->page;
cpu_buffer->reader_page->page = *data_page;
cpu_buffer->reader_page->read = 0;
bpage = reader->page;
reader->page = *data_page;
local_set(&reader->write, 0);
reader->read = 0;
*data_page = bpage;
/* update the entry counter */
rb_remove_entries(cpu_buffer, bpage, read);
}
ret = read;
/* update the entry counter */
rb_remove_entries(cpu_buffer, bpage, read);
out:
spin_unlock_irqrestore(&cpu_buffer->reader_lock, flags);
......
......@@ -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"
......@@ -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)
......@@ -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;
......@@ -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,
......
......@@ -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;
......
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