On 06/14, zhangwei(Jovi) wrote:
>
> 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)
And the change in probe_event_enable() doesn't look right, but
let me repeat I didn't read the patch carefully yet.
> +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);
Do we really need this? Can't we really on mutex_event hold by the caller?
> 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;
So it can set both TP_FLAG_TRACE and TP_FLAG_PROFILE, yes?
If yes, this is not right. Until we change the pre-filtering at least.
Currently TP_FLAG_TRACE/TP_FLAG_PROFILE are mutually exclusive.
I think it makes sense to remove this limitation anyway, and in fact
I do not remember why I didn't do this... But this needs a separate
change.
Oleg.
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