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Date: Fri, 17 Jan 2014 17:08:38 +0900
From: Namhyung Kim <namhyung@...nel.org>
To: Steven Rostedt <rostedt@...dmis.org>
Cc: Frederic Weisbecker <fweisbec@...il.com>,
Ingo Molnar <mingo@...nel.org>,
LKML <linux-kernel@...r.kernel.org>,
Namhyung Kim <namhyung.kim@....com>,
"zhangwei(Jovi)" <jovi.zhangwei@...wei.com>,
Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Subject: [PATCH 3/5] tracing/uprobes: Support ftrace_event_file base multibuffer
From: "zhangwei(Jovi)" <jovi.zhangwei@...wei.com>
Support multi-buffer on uprobe-based dynamic events by
using ftrace_event_file.
This patch is based kprobe-based dynamic events multibuffer
support work initially, commited by Masami(commit 41a7dd420c),
but revised as below:
Oleg changed the kprobe-based multibuffer design from
array-pointers of ftrace_event_file into simple list,
so this patch also change to the list design.
rcu_read_lock/unlock added into uprobe_trace_func/uretprobe_trace_func,
to synchronize with ftrace_event_file list add and delete.
Even though we allow multi-uprobes instances now,
but TP_FLAG_PROFILE/TP_FLAG_TRACE are still mutually exclusive
in probe_event_enable currently, this means we cannot allow
one user is using uprobe-tracer, and another user is using
perf-probe on same uprobe concurrently.
(Perhaps this will be fix in future, kprobe don't have this
limitation now)
Signed-off-by: zhangwei(Jovi) <jovi.zhangwei@...wei.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Reviewed-by: Oleg Nesterov <oleg@...hat.com>
Cc: Frederic Weisbecker <fweisbec@...il.com>
Cc: Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Signed-off-by: Namhyung Kim <namhyung@...nel.org>
---
kernel/trace/trace_kprobe.c | 17 -------
kernel/trace/trace_probe.h | 17 +++++++
kernel/trace/trace_uprobe.c | 105 +++++++++++++++++++++++++++++++++++---------
3 files changed, 101 insertions(+), 38 deletions(-)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index bdbae450c13e..d021d21dd150 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -35,11 +35,6 @@ struct trace_kprobe {
struct trace_probe tp;
};
-struct event_file_link {
- struct ftrace_event_file *file;
- struct list_head list;
-};
-
#define SIZEOF_TRACE_KPROBE(n) \
(offsetof(struct trace_kprobe, tp.args) + \
(sizeof(struct probe_arg) * (n)))
@@ -387,18 +382,6 @@ enable_trace_kprobe(struct trace_kprobe *tk, struct ftrace_event_file *file)
return ret;
}
-static struct event_file_link *
-find_event_file_link(struct trace_probe *tp, struct ftrace_event_file *file)
-{
- struct event_file_link *link;
-
- list_for_each_entry(link, &tp->files, list)
- if (link->file == file)
- return link;
-
- return NULL;
-}
-
/*
* Disable trace_probe
* if the file is NULL, disable "perf" handler, or disable "trace" handler.
diff --git a/kernel/trace/trace_probe.h b/kernel/trace/trace_probe.h
index b73574a5f429..fb1ab5dfbd42 100644
--- a/kernel/trace/trace_probe.h
+++ b/kernel/trace/trace_probe.h
@@ -288,6 +288,11 @@ struct trace_probe {
struct probe_arg args[];
};
+struct event_file_link {
+ struct ftrace_event_file *file;
+ struct list_head list;
+};
+
static inline bool trace_probe_is_enabled(struct trace_probe *tp)
{
return !!(tp->flags & (TP_FLAG_TRACE | TP_FLAG_PROFILE));
@@ -316,6 +321,18 @@ static inline int is_good_name(const char *name)
return 1;
}
+static inline struct event_file_link *
+find_event_file_link(struct trace_probe *tp, struct ftrace_event_file *file)
+{
+ struct event_file_link *link;
+
+ list_for_each_entry(link, &tp->files, list)
+ if (link->file == file)
+ return link;
+
+ return NULL;
+}
+
extern int traceprobe_parse_probe_arg(char *arg, ssize_t *size,
struct probe_arg *parg, bool is_return, bool is_kprobe);
diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c
index d83155e0da78..349c6df9e332 100644
--- a/kernel/trace/trace_uprobe.c
+++ b/kernel/trace/trace_uprobe.c
@@ -260,6 +260,7 @@ alloc_trace_uprobe(const char *group, const char *event, int nargs, bool is_ret)
goto error;
INIT_LIST_HEAD(&tu->list);
+ INIT_LIST_HEAD(&tu->tp.files);
tu->consumer.handler = uprobe_dispatcher;
if (is_ret)
tu->consumer.ret_handler = uretprobe_dispatcher;
@@ -760,7 +761,8 @@ static void uprobe_buffer_put(struct uprobe_cpu_buffer *ucb)
static void __uprobe_trace_func(struct trace_uprobe *tu,
unsigned long func, struct pt_regs *regs,
- struct uprobe_cpu_buffer *ucb, int dsize)
+ struct uprobe_cpu_buffer *ucb, int dsize,
+ struct ftrace_event_file *ftrace_file)
{
struct uprobe_trace_entry_head *entry;
struct ring_buffer_event *event;
@@ -769,13 +771,15 @@ static void __uprobe_trace_func(struct trace_uprobe *tu,
int size, esize;
struct ftrace_event_call *call = &tu->tp.call;
+ WARN_ON(call != ftrace_file->event_call);
+
if (WARN_ON_ONCE(tu->tp.size + dsize > PAGE_SIZE))
return;
esize = SIZEOF_TRACE_ENTRY(is_ret_probe(tu));
size = esize + tu->tp.size + dsize;
- event = trace_current_buffer_lock_reserve(&buffer, call->event.type,
- size, 0, 0);
+ event = trace_event_buffer_lock_reserve(&buffer, ftrace_file,
+ call->event.type, size, 0, 0);
if (!event)
return;
@@ -799,8 +803,16 @@ static void __uprobe_trace_func(struct trace_uprobe *tu,
static int uprobe_trace_func(struct trace_uprobe *tu, struct pt_regs *regs,
struct uprobe_cpu_buffer *ucb, int dsize)
{
- if (!is_ret_probe(tu))
- __uprobe_trace_func(tu, 0, regs, ucb, dsize);
+ struct event_file_link *link;
+
+ if (is_ret_probe(tu))
+ return 0;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(link, &tu->tp.files, list)
+ __uprobe_trace_func(tu, 0, regs, ucb, dsize, link->file);
+ rcu_read_unlock();
+
return 0;
}
@@ -808,7 +820,12 @@ static void uretprobe_trace_func(struct trace_uprobe *tu, unsigned long func,
struct pt_regs *regs,
struct uprobe_cpu_buffer *ucb, int dsize)
{
- __uprobe_trace_func(tu, func, regs, ucb, dsize);
+ struct event_file_link *link;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(link, &tu->tp.files, list)
+ __uprobe_trace_func(tu, func, regs, ucb, dsize, link->file);
+ rcu_read_unlock();
}
/* Event entry printers */
@@ -855,12 +872,31 @@ 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 ret = 0;
+ bool enabled = trace_probe_is_enabled(&tu->tp);
+ struct event_file_link *link = NULL;
+ int ret;
+
+ if (file) {
+ if (tu->tp.flags & TP_FLAG_PROFILE)
+ return -EINTR;
- if (trace_probe_is_enabled(&tu->tp))
- return -EINTR;
+ link = kmalloc(sizeof(*link), GFP_KERNEL);
+ if (!link)
+ return -ENOMEM;
+
+ link->file = file;
+ list_add_tail_rcu(&link->list, &tu->tp.files);
+
+ tu->tp.flags |= TP_FLAG_TRACE;
+ } else {
+ if (tu->tp.flags & TP_FLAG_TRACE)
+ return -EINTR;
+
+ tu->tp.flags |= TP_FLAG_PROFILE;
+ }
ret = uprobe_buffer_enable();
if (ret < 0)
@@ -868,24 +904,49 @@ probe_event_enable(struct trace_uprobe *tu, int flag, filter_func_t filter)
WARN_ON(!uprobe_filter_is_empty(&tu->filter));
- tu->tp.flags |= flag;
+ if (enabled)
+ return 0;
+
tu->consumer.filter = filter;
ret = uprobe_register(tu->inode, tu->offset, &tu->consumer);
- if (ret)
- tu->tp.flags &= ~flag;
+ if (ret) {
+ if (file) {
+ list_del(&link->list);
+ kfree(link);
+ tu->tp.flags &= ~TP_FLAG_TRACE;
+ } else
+ tu->tp.flags &= ~TP_FLAG_PROFILE;
+ }
return ret;
}
-static void probe_event_disable(struct trace_uprobe *tu, int flag)
+static void
+probe_event_disable(struct trace_uprobe *tu, struct ftrace_event_file *file)
{
if (!trace_probe_is_enabled(&tu->tp))
return;
+ if (file) {
+ struct event_file_link *link;
+
+ link = find_event_file_link(&tu->tp, file);
+ if (!link)
+ return;
+
+ list_del_rcu(&link->list);
+ /* synchronize with u{,ret}probe_trace_func */
+ synchronize_sched();
+ kfree(link);
+
+ if (!list_empty(&tu->tp.files))
+ return;
+ }
+
WARN_ON(!uprobe_filter_is_empty(&tu->filter));
uprobe_unregister(tu->inode, tu->offset, &tu->consumer);
- tu->tp.flags &= ~flag;
+ tu->tp.flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE;
uprobe_buffer_disable();
}
@@ -1077,25 +1138,27 @@ static void uretprobe_perf_func(struct trace_uprobe *tu, unsigned long func,
}
#endif /* CONFIG_PERF_EVENTS */
-static
-int trace_uprobe_register(struct ftrace_event_call *event, enum trace_reg type, void *data)
+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:
--
1.7.11.7
--
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