[ltt-dev] [PATCH] LTTng: Make mark-control work in debugfs
Mathieu Desnoyers
compudj at krystal.dyndns.org
Wed Feb 11 11:56:48 EST 2009
* Gui Jianfeng (guijianfeng at cn.fujitsu.com) wrote:
> Mathieu Desnoyers wrote:
> > I think I have an idea we could implement to support arming markers
> > which are not loaded in the kernel yet. The use-case is :
> >
> > We have a marker in a given module, which is not loaded. We are
> > interested in tracing events in this module happening soon after module
> > load. Therefore, we cannot use the /mnt/debugfs/ltt/markers/**/* files,
> > because the marker is not present yet.
> >
> > We could implement mkdir operations to support this. This is out of
> > ltt-armall scope, and people would have to use it manually and *know*
> > what channel and marker names they want to enable, but I think it's ok.
> >
> > So basically, we would have :
> >
> > cd /mnt/debugfs/ltt
> > mkdir channel_name
> > cd channel_name
> > mkdir marker_name
> >
> > The marker_name subdirectory would be populated with standard
> > information and enable files.
>
> Do you mean if we do "mkdir channel_name" and "mkdir marker_name"
> kernel will automatically insert the probe module, but in debugfs,
> it doesn't show all of the markers this module have, but just the
> requested one?
>
No. I mean that doing :
mkdir channel_name
mkdir channel_name/marker_name
echo 1 > channel_name/marker_name
Should be the same as the
echo "connect channel_name marker_name" > /proc/ltt
This worked even if the channel/marker pair were not listed in
/proc/ltt.
This would create the directories locally even if they do not exist in
the marker table, and call ltt_marker_connect() when echo 1 >
channel_name/marker_name is done.
Mathieu
> >
> > Do you think it could be added easily to ltt-trace-control ?
> >
> > Mathieu
> >
> >
> >> Thanks,
> >>
> >> Mathieu
> >>
> >>>> I'm providing the patch modified to fit with checkpatch below.
> >>>>
> >>>> Thanks,
> >>>>
> >>>> Mathieu
> >>>>
> >>>>
> >>>> lttng-make-mark-control-work-in-debugfs
> >>>>
> >>>> This patch makes mark-control work in debugfs
> >>>> Control files are organized as following.
> >>>> ltt/
> >>>> |-- markers
> >>>> | |-- fs
> >>>> | | |-- buffer_wait_end
> >>>> | | | |-- enable
> >>>> | | | `-- info
> >>>> | | |-- buffer_wait_start
> >>>> | | | |-- enable
> >>>> | | | `-- info
> >>>> | | |-- close
> >>>> | | | |-- enable
> >>>> | | | `-- info
> >>>> | | |-- exec
> >>>> | | | |-- enable
> >>>> | | | `-- info
> >>>> ...
> >>>>
> >>>> One can enable or disable a marker by using the following command
> >>>> # echo 1 > ltt/markers/fs/close/enable
> >>>> # echo 0 > ltt/markers/fs/close/enable
> >>>>
> >>>> Show the marker information as following
> >>>> # cat ltt/markers/fs/close/info
> >>>> format: "fd %u"
> >>>> state: 1
> >>>> event_id: 2
> >>>> call: 0xc0459118
> >>>> probe single : 0xc04f7b08
> >>>>
> >>>> Mathieu :
> >>>>
> >>>> enabled -> enable to follow the semantic of the rest of the debugfs API.
> >>>> checkpatch.pl cleanup.
> >>>>
> >>>> Signed-off-by: Gui Jianfeng <guijianfeng at cn.fujitsu.com>
> >>>> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers at polymtl.ca>
> >>>> ---
> >>>> ltt/ltt-trace-control.c | 298 +++++++++++++++++++++++++++++++++++++++++++++++-
> >>>> 1 file changed, 294 insertions(+), 4 deletions(-)
> >>>>
> >>>> Index: linux-2.6-lttng/ltt/ltt-trace-control.c
> >>>> ===================================================================
> >>>> --- linux-2.6-lttng.orig/ltt/ltt-trace-control.c 2009-02-04 00:56:05.000000000 -0500
> >>>> +++ linux-2.6-lttng/ltt/ltt-trace-control.c 2009-02-04 01:01:46.000000000 -0500
> >>>> @@ -1,8 +1,10 @@
> >>>> /*
> >>>> * LTT trace control module over debugfs.
> >>>> *
> >>>> - * Copyright 2008 -
> >>>> - * Zhaolei <zhaolei at cn.fujitsu.com>
> >>>> + * Copyright 2008 - Zhaolei <zhaolei at cn.fujitsu.com>
> >>>> + *
> >>>> + * Copyright 2009 - Gui Jianfeng <guijianfeng at cn.fujitsu.com>
> >>>> + * Make mark-control work in debugfs
> >>>> */
> >>>>
> >>>> /*
> >>>> @@ -16,14 +18,17 @@
> >>>> #include <linux/uaccess.h>
> >>>> #include <linux/debugfs.h>
> >>>> #include <linux/ltt-tracer.h>
> >>>> +#include <linux/notifier.h>
> >>>>
> >>>> #define LTT_CONTROL_DIR "control"
> >>>> +#define MARKERS_CONTROL_DIR "markers"
> >>>> #define LTT_SETUP_TRACE_FILE "setup_trace"
> >>>> #define LTT_DESTROY_TRACE_FILE "destroy_trace"
> >>>>
> >>>> #define LTT_WRITE_MAXLEN (128)
> >>>>
> >>>> -struct dentry *ltt_control_dir, *ltt_setup_trace_file, *ltt_destroy_trace_file;
> >>>> +struct dentry *ltt_control_dir, *ltt_setup_trace_file, *ltt_destroy_trace_file,
> >>>> + *markers_control_dir;
> >>>>
> >>>> /*
> >>>> * the traces_lock nests inside control_lock.
> >>>> @@ -692,6 +697,270 @@ static struct file_operations ltt_destro
> >>>> .write = destroy_trace_write,
> >>>> };
> >>>>
> >>>> +static int marker_enable_open(struct inode *inode, struct file *filp)
> >>>> +{
> >>>> + filp->private_data = inode->i_private;
> >>>> + return 0;
> >>>> +}
> >>>> +
> >>>> +static ssize_t marker_enable_read(struct file *filp, char __user *ubuf,
> >>>> + size_t cnt, loff_t *ppos)
> >>>> +{
> >>>> + struct marker *marker;
> >>>> + char *buf;
> >>>> + int len;
> >>>> +
> >>>> + marker = (struct marker *)filp->private_data;
> >>>> + buf = kmalloc(1024, GFP_KERNEL);
> >>>> +
> >>>> + len = sprintf(buf, "%d\n", _imv_read(marker->state));
> >>>> +
> >>>> + len = simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
> >>>> + kfree(buf);
> >>>> +
> >>>> + return len;
> >>>> +}
> >>>> +
> >>>> +static ssize_t marker_enable_write(struct file *filp, const char __user *ubuf,
> >>>> + size_t cnt, loff_t *ppos)
> >>>> +{
> >>>> + char buf[NAME_MAX];
> >>>> + int buf_size;
> >>>> + int err = 0;
> >>>> + struct marker *marker;
> >>>> +
> >>>> + marker = (struct marker *)filp->private_data;
> >>>> + buf_size = min(cnt, sizeof(buf) - 1);
> >>>> + err = copy_from_user(buf, ubuf, buf_size);
> >>>> + if (err)
> >>>> + return err;
> >>>> +
> >>>> + buf[buf_size] = 0;
> >>>> +
> >>>> + switch (buf[0]) {
> >>>> + case 'Y':
> >>>> + case 'y':
> >>>> + case '1':
> >>>> + err = ltt_marker_connect(marker->channel, marker->name,
> >>>> + "default");
> >>>> + if (err)
> >>>> + return err;
> >>>> + break;
> >>>> + case 'N':
> >>>> + case 'n':
> >>>> + case '0':
> >>>> + err = ltt_marker_disconnect(marker->channel, marker->name,
> >>>> + "default");
> >>>> + if (err)
> >>>> + return err;
> >>>> + break;
> >>>> + default:
> >>>> + return -EPERM;
> >>>> + }
> >>>> +
> >>>> + return cnt;
> >>>> +}
> >>>> +
> >>>> +static const struct file_operations enable_fops = {
> >>>> + .open = marker_enable_open,
> >>>> + .read = marker_enable_read,
> >>>> + .write = marker_enable_write,
> >>>> +};
> >>>> +
> >>>> +static int marker_info_open(struct inode *inode, struct file *filp)
> >>>> +{
> >>>> + filp->private_data = inode->i_private;
> >>>> + return 0;
> >>>> +}
> >>>> +
> >>>> +static ssize_t marker_info_read(struct file *filp, char __user *ubuf,
> >>>> + size_t cnt, loff_t *ppos)
> >>>> +{
> >>>> + struct marker *marker;
> >>>> + char *buf;
> >>>> + int len;
> >>>> +
> >>>> + marker = (struct marker *)filp->private_data;
> >>>> + buf = kmalloc(1024, GFP_KERNEL);
> >>>> +
> >>>> + len = sprintf(buf, "format: \"%s\"\nstate: %d\n"
> >>>> + "event_id: %hu\n"
> >>>> + "call: 0x%p\n"
> >>>> + "probe %s : 0x%p\n",
> >>>> + marker->format, _imv_read(marker->state),
> >>>> + marker->event_id, marker->call, marker->ptype ?
> >>>> + "multi" : "single", marker->ptype ?
> >>>> + (void *)marker->multi : (void *)marker->single.func);
> >>>> +
> >>>> + len = simple_read_from_buffer(ubuf, cnt, ppos, buf, len);
> >>>> + kfree(buf);
> >>>> +
> >>>> + return len;
> >>>> +}
> >>>> +
> >>>> +static const struct file_operations info_fops = {
> >>>> + .open = marker_info_open,
> >>>> + .read = marker_info_read,
> >>>> +};
> >>>> +
> >>>> +static int build_marker_file(struct marker *marker)
> >>>> +{
> >>>> + struct dentry *channel_d, *marker_d, *enable_d, *info_d;
> >>>> + int err;
> >>>> +
> >>>> + channel_d = dir_lookup(markers_control_dir, marker->channel);
> >>>> + if (!channel_d) {
> >>>> + channel_d = debugfs_create_dir(marker->channel,
> >>>> + markers_control_dir);
> >>>> + if (IS_ERR(channel_d) || !channel_d) {
> >>>> + printk(KERN_ERR
> >>>> + "%s: build channel dir of %s failed\n",
> >>>> + __func__, marker->channel);
> >>>> + err = -ENOMEM;
> >>>> + goto err_build_fail;
> >>>> + }
> >>>> + }
> >>>> +
> >>>> + marker_d = dir_lookup(channel_d, marker->name);
> >>>> + if (!marker_d) {
> >>>> + marker_d = debugfs_create_dir(marker->name, channel_d);
> >>>> + if (IS_ERR(marker_d) || !marker_d) {
> >>>> + printk(KERN_ERR
> >>>> + "%s: marker dir of %s failed\n",
> >>>> + __func__, marker->name);
> >>>> + err = -ENOMEM;
> >>>> + goto err_build_fail;
> >>>> + }
> >>>> + }
> >>>> +
> >>>> + enable_d = dir_lookup(marker_d, "enable");
> >>>> + if (!enable_d) {
> >>>> + enable_d = debugfs_create_file("enable", 0644, marker_d,
> >>>> + marker, &enable_fops);
> >>>> + if (IS_ERR(enable_d) || !enable_d) {
> >>>> + printk(KERN_ERR
> >>>> + "%s: create file of %s failed\n",
> >>>> + __func__, "enable");
> >>>> + err = -ENOMEM;
> >>>> + goto err_build_fail;
> >>>> + }
> >>>> + }
> >>>> +
> >>>> + info_d = dir_lookup(marker_d, "info");
> >>>> + if (!info_d) {
> >>>> + info_d = debugfs_create_file("info", 0444, marker_d,
> >>>> + marker, &info_fops);
> >>>> + if (IS_ERR(info_d) || !info_d) {
> >>>> + printk(KERN_ERR
> >>>> + "%s: create file of %s failed\n",
> >>>> + __func__, "enable");
> >>>> + err = -ENOMEM;
> >>>> + goto err_build_fail;
> >>>> + }
> >>>> + }
> >>>> +
> >>>> + return 0;
> >>>> +
> >>>> +err_build_fail:
> >>>> + return err;
> >>>> +}
> >>>> +
> >>>> +static int build_marker_control_files(void)
> >>>> +{
> >>>> + struct marker_iter iter;
> >>>> + int err;
> >>>> +
> >>>> + err = 0;
> >>>> + if (!markers_control_dir)
> >>>> + return -EEXIST;
> >>>> +
> >>>> + marker_iter_reset(&iter);
> >>>> + marker_iter_start(&iter);
> >>>> + for (; iter.marker != NULL; marker_iter_next(&iter)) {
> >>>> + err = build_marker_file(iter.marker);
> >>>> + if (err)
> >>>> + goto err_build_fail;
> >>>> + }
> >>>> + marker_iter_stop(&iter);
> >>>> + return 0;
> >>>> +
> >>>> +err_build_fail:
> >>>> + return err;
> >>>> +}
> >>>> +
> >>>> +static int remove_marker_control_dir(struct marker *marker)
> >>>> +{
> >>>> + struct dentry *channel_d, *marker_d;
> >>>> +
> >>>> + channel_d = dir_lookup(markers_control_dir, marker->channel);
> >>>> + if (!channel_d)
> >>>> + return -ENOENT;
> >>>> +
> >>>> + marker_d = dir_lookup(channel_d, marker->name);
> >>>> + if (!marker_d)
> >>>> + return -ENOENT;
> >>>> +
> >>>> + debugfs_remove_recursive(marker_d);
> >>>> + if (list_empty(&channel_d->d_subdirs))
> >>>> + debugfs_remove(channel_d);
> >>>> +
> >>>> + return 0;
> >>>> +}
> >>>> +
> >>>> +static void cleanup_control_dir(struct marker *begin, struct marker *end)
> >>>> +{
> >>>> + struct marker *iter;
> >>>> +
> >>>> + if (!markers_control_dir)
> >>>> + return;
> >>>> +
> >>>> + for (iter = begin; iter < end; iter++)
> >>>> + remove_marker_control_dir(iter);
> >>>> +
> >>>> + return;
> >>>> +}
> >>>> +
> >>>> +static void build_control_dir(struct marker *begin, struct marker *end)
> >>>> +{
> >>>> + struct marker *iter;
> >>>> + int err;
> >>>> +
> >>>> + err = 0;
> >>>> + if (!markers_control_dir)
> >>>> + return;
> >>>> +
> >>>> + for (iter = begin; iter < end; iter++) {
> >>>> + err = build_marker_file(iter);
> >>>> + if (err)
> >>>> + goto err_build_fail;
> >>>> + }
> >>>> +
> >>>> + return;
> >>>> +err_build_fail:
> >>>> + cleanup_control_dir(begin, end);
> >>>> +}
> >>>> +
> >>>> +static int module_notify(struct notifier_block *self,
> >>>> + unsigned long val, void *data)
> >>>> +{
> >>>> + struct module *mod = data;
> >>>> +
> >>>> + switch (val) {
> >>>> + case MODULE_STATE_COMING:
> >>>> + build_control_dir(mod->markers,
> >>>> + mod->markers + mod->num_markers);
> >>>> + break;
> >>>> + case MODULE_STATE_GOING:
> >>>> + cleanup_control_dir(mod->markers,
> >>>> + mod->markers + mod->num_markers);
> >>>> + break;
> >>>> + }
> >>>> + return NOTIFY_DONE;
> >>>> +}
> >>>> +
> >>>> +static struct notifier_block module_nb = {
> >>>> + .notifier_call = module_notify,
> >>>> +};
> >>>>
> >>>> static int __init ltt_trace_control_init(void)
> >>>> {
> >>>> @@ -733,8 +1002,27 @@ static int __init ltt_trace_control_init
> >>>> goto err_create_destroy_trace_file;
> >>>> }
> >>>>
> >>>> - return 0;
> >>>> + markers_control_dir = debugfs_create_dir(MARKERS_CONTROL_DIR,
> >>>> + ltt_root_dentry);
> >>>> + if (IS_ERR(markers_control_dir) || !markers_control_dir) {
> >>>> + printk(KERN_ERR
> >>>> + "ltt_channel_control_init: create dir of %s failed\n",
> >>>> + MARKERS_CONTROL_DIR);
> >>>> + err = -ENOMEM;
> >>>> + goto err_create_marker_control_dir;
> >>>> + }
> >>>>
> >>>> + if (build_marker_control_files())
> >>>> + goto err_build_fail;
> >>>> +
> >>>> + if (!register_module_notifier(&module_nb))
> >>>> + return 0;
> >>>> +
> >>>> +err_build_fail:
> >>>> + debugfs_remove_recursive(markers_control_dir);
> >>>> + markers_control_dir = NULL;
> >>>> +err_create_marker_control_dir:
> >>>> + debugfs_remove(ltt_destroy_trace_file);
> >>>> err_create_destroy_trace_file:
> >>>> debugfs_remove(ltt_setup_trace_file);
> >>>> err_create_setup_trace_file:
> >>>> @@ -759,6 +1047,8 @@ static void __exit ltt_trace_control_exi
> >>>> debugfs_remove(ltt_setup_trace_file);
> >>>> debugfs_remove(ltt_destroy_trace_file);
> >>>> debugfs_remove_recursive(ltt_control_dir);
> >>>> + debugfs_remove_recursive(markers_control_dir);
> >>>> + unregister_module_notifier(&module_nb);
> >>>> }
> >>>>
> >>>> module_init(ltt_trace_control_init);
> >>>>
> >>>>
> >>> --
> >>> Regards
> >>> Gui Jianfeng
> >>>
> >>>
> >>>
> >>> _______________________________________________
> >>> ltt-dev mailing list
> >>> ltt-dev at lists.casi.polymtl.ca
> >>> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
> >>>
> >> --
> >> Mathieu Desnoyers
> >> OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
> >
>
> --
> Regards
> Gui Jianfeng
>
> _______________________________________________
> ltt-dev mailing list
> ltt-dev at lists.casi.polymtl.ca
> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
>
--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
More information about the lttng-dev
mailing list