Support multi-buffer on uprobe-based dynamic events by
using ftrace_event_file.
The code change is based on kprobe-based dynamic events
multibuffer support work commited by Masami(commit 41a7dd420c)
Signed-off-by: zhangwei(Jovi) <jovi.zhang...@huawei.com>
Cc: Masami Hiramatsu <masami.hiramatsu...@hitachi.com>
Cc: Frederic Weisbecker <fweis...@gmail.com>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: Srikar Dronamraju <sri...@linux.vnet.ibm.com>
---
kernel/trace/trace_uprobe.c | 183 +++++++++++++++++++++++++++++++++++++------
1 file changed, 161 insertions(+), 22 deletions(-)
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index d5d0cd3..31f08d6 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -53,6 +53,7 @@ struct trace_uprobe {
struct list_head list;
struct ftrace_event_class class;
struct ftrace_event_call call;
+ struct ftrace_event_file * __rcu *files;
struct trace_uprobe_filter filter;
struct uprobe_consumer consumer;
struct inode *inode;
@@ -513,7 +514,8 @@ static const struct file_operations uprobe_profile_ops = {
};
static void uprobe_trace_print(struct trace_uprobe *tu,
- unsigned long func, struct pt_regs *regs)
+ unsigned long func, struct pt_regs *regs,
+ struct ftrace_event_file *ftrace_file)
{
struct uprobe_trace_entry_head *entry;
struct ring_buffer_event *event;
@@ -522,9 +524,15 @@ static void uprobe_trace_print(struct trace_uprobe *tu,
int size, i;
struct ftrace_event_call *call = &tu->call;
+ WARN_ON(call != ftrace_file->event_call);
+
+ if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags))
+ return;
+
size = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
- event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
- size + tu->size, 0, 0);
+ event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
+ call->event.type,
+ size + tu->size, 0, 0);
if (!event)
return;
@@ -548,15 +556,35 @@ static void uprobe_trace_print(struct trace_uprobe *tu,
/* uprobe handler */
static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs)
{
- if (!is_ret_probe(tu))
- uprobe_trace_print(tu, 0, regs);
+ struct ftrace_event_file **file;
+
+ if (is_ret_probe(tu))
+ return 0;
+
+ file = rcu_dereference_raw(tu->files);
+ if (unlikely(!file))
+ return 0;
+
+ while (*file) {
+ uprobe_trace_print(tu, 0, regs, *file);
+ file++;
+ }
+
return 0;
}
static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
struct pt_regs *regs)
{
- uprobe_trace_print(tu, func, regs);
+ struct ftrace_event_file **file = rcu_dereference_raw(tu->files);
+
+ if (unlikely(!file))
+ return;
+
+ while (*file) {
+ uprobe_trace_print(tu, func, regs, *file);
+ file++;
+ }
}
/* Event entry printers */
@@ -597,6 +625,26 @@ partial:
return TRACE_TYPE_PARTIAL_LINE;
}
+
+static int trace_uprobe_nr_files(struct trace_uprobe *tu)
+{
+ struct ftrace_event_file **file;
+ int ret = 0;
+
+ /*
+ * Since all tu->files updater is protected by uprobe_enable_lock,
+ * we don't need to lock an rcu_read_lock.
+ */
+ file = rcu_dereference_raw(tu->files);
+ if (file)
+ while (*(file++))
+ ret++;
+
+ return ret;
+}
+
+static DEFINE_MUTEX(uprobe_enable_lock);
+
static inline bool is_trace_uprobe_enabled(struct trace_uprobe *tu)
{
return tu->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE);
@@ -607,33 +655,123 @@ typedef bool (*filter_func_t)(struct uprobe_consumer
*self,
struct mm_struct *mm);
static int
-probe_event_enable(struct trace_uprobe *tu, int flag, filter_func_t filter)
+probe_event_enable(struct trace_uprobe *tu, struct ftrace_event_file *file,
+ filter_func_t filter)
{
+ int enabled = 0;
int ret = 0;
+ mutex_lock(&uprobe_enable_lock);
+
if (is_trace_uprobe_enabled(tu))
- return -EINTR;
+ enabled = 1;
+
+ if (file) {
+ struct ftrace_event_file **new, **old;
+ int n = trace_uprobe_nr_files(tu);
+
+ old = rcu_dereference_raw(tu->files);
+ /* 1 is for new one and 1 is for stopper */
+ new = kzalloc((n + 2) * sizeof(struct ftrace_event_file *),
+ GFP_KERNEL);
+ if (!new) {
+ ret = -ENOMEM;
+ goto out_unlock;
+ }
+ memcpy(new, old, n * sizeof(struct ftrace_event_file *));
+ new[n] = file;
+ /* The last one keeps a NULL */
+
+ rcu_assign_pointer(tu->files, new);
+ tu->flags |= TP_FLAG_TRACE;
+
+ if (old) {
+ /* Make sure the probe is done with old files */
+ synchronize_sched();
+ kfree(old);
+ }
+ } else
+ tu->flags |= TP_FLAG_PROFILE;
WARN_ON(!uprobe_filter_is_empty(&tu->filter));
- tu->flags |= flag;
- tu->consumer.filter = filter;
- ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
- if (ret)
- tu->flags &= ~flag;
+ if (!enabled) {
+ tu->consumer.filter = filter;
+ ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
+ if (ret)
+ tu->flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE;
+ }
+ out_unlock:
+ mutex_unlock(&uprobe_enable_lock);
return ret;
}
-static void probe_event_disable(struct trace_uprobe *tu, int flag)
+static int
+trace_uprobe_file_index(struct trace_uprobe *tu, struct ftrace_event_file
*file)
{
- if (!is_trace_uprobe_enabled(tu))
- return;
+ struct ftrace_event_file **files;
+ int i;
+
+ /*
+ * Since all tu->files updater is protected by uprobe_enable_lock,
+ * we don't need to lock an rcu_read_lock.
+ */
+ files = rcu_dereference_raw(tu->files);
+ if (files) {
+ for (i = 0; files[i]; i++)
+ if (files[i] == file)
+ return i;
+ }
+
+ return -1;
+}
+
+static void
+probe_event_disable(struct trace_uprobe *tu, struct ftrace_event_file *file)
+{
+ mutex_lock(&uprobe_enable_lock);
+
+ if (file) {
+ struct ftrace_event_file **new, **old;
+ int n = trace_uprobe_nr_files(tu);
+ int i, j;
+
+ old = rcu_dereference_raw(tu->files);
+ if (n == 0 || trace_uprobe_file_index(tu, file) < 0)
+ goto out_unlock;
+
+ if (n == 1) { /* Remove the last file */
+ tu->flags &= ~TP_FLAG_TRACE;
+ new = NULL;
+ } else {
+ new = kzalloc(n * sizeof(struct ftrace_event_file *),
+ GFP_KERNEL);
+ if (!new)
+ goto out_unlock;
+
+ /* This copy & check loop copies the NULL stopper too */
+ for (i = 0, j = 0; j < n && i < n + 1; i++)
+ if (old[i] != file)
+ new[j++] = old[i];
+ }
+
+ rcu_assign_pointer(tu->files, new);
+
+ /* Make sure the probe is done with old files */
+ synchronize_sched();
+ kfree(old);
+ } else
+ tu->flags &= ~TP_FLAG_PROFILE;
+
WARN_ON(!uprobe_filter_is_empty(&tu->filter));
- uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
- tu->flags &= ~flag;
+ if (!is_trace_uprobe_enabled(tu))
+ uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
+
+ out_unlock:
+ mutex_unlock(&uprobe_enable_lock);
}
static int uprobe_event_define_fields(struct ftrace_event_call *event_call)
@@ -869,21 +1007,22 @@ static
int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg
type, void *data)
{
struct trace_uprobe *tu = event->data;
+ struct ftrace_event_file *file = data;
switch (type) {
case TRACE_REG_REGISTER:
- return probe_event_enable(tu, TP_FLAG_TRACE, NULL);
+ return probe_event_enable(tu, file, NULL);
case TRACE_REG_UNREGISTER:
- probe_event_disable(tu, TP_FLAG_TRACE);
+ probe_event_disable(tu, file);
return 0;
#ifdef CONFIG_PERF_EVENTS
case TRACE_REG_PERF_REGISTER:
- return probe_event_enable(tu, TP_FLAG_PROFILE,
uprobe_perf_filter);
+ return probe_event_enable(tu, NULL, uprobe_perf_filter);
case TRACE_REG_PERF_UNREGISTER:
- probe_event_disable(tu, TP_FLAG_PROFILE);
+ probe_event_disable(tu, NULL);
return 0;
case TRACE_REG_PERF_OPEN:
--
1.7.9.7
--
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