Hi Jovi, Just a few of dummy questions..
On Thu, 4 Jul 2013 15:01:10 +0800, zhangwei wrote: > 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 dont't have this > limitation now) So why does this limitation exist? Didn't we support this kind of thing in the original code? > > Signed-off-by: zhangwei(Jovi) <[email protected]> > Cc: Masami Hiramatsu <[email protected]> > Cc: Frederic Weisbecker <[email protected]> > Cc: Oleg Nesterov <[email protected]> > Cc: Srikar Dronamraju <[email protected]> > --- [SNIP] > + rcu_read_lock(); > + list_for_each_entry(link, &tu->files, list) list_for_each_entry_rcu() ? > + uprobe_trace_print(tu, 0, regs, link->file); > + rcu_read_unlock(); > + > 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 event_file_link *link; > + > + rcu_read_lock(); > + list_for_each_entry(link, &tu->files, list) Ditto. > + uprobe_trace_print(tu, func, regs, link->file); > + rcu_read_unlock(); > } [SNIP] > -static void probe_event_disable(struct trace_uprobe *tu, int flag) > +static struct event_file_link * > +find_event_file_link(struct trace_uprobe *tu, struct ftrace_event_file *file) > +{ > + struct event_file_link *link; > + > + list_for_each_entry(link, &tu->files, list) Not sure of this case. ;) Thanks, Namhyung > + if (link->file == file) > + return link; > + > + return NULL; > +} > + > +static void > +probe_event_disable(struct trace_uprobe *tu, struct ftrace_event_file *file) > { > if (!is_trace_uprobe_enabled(tu)) > return; > > + if (file) { > + struct event_file_link *link; > + > + link = find_event_file_link(tu, file); > + if (!link) > + return; > + > + list_del_rcu(&link->list); > + /* synchronize with uprobe_trace_func/uretprobe_trace_func */ > + synchronize_sched(); > + kfree(link); > + > + if (!list_empty(&tu->files)) > + return; > + } > + > WARN_ON(!uprobe_filter_is_empty(&tu->filter)); > > uprobe_unregister(tu->inode, tu->offset, &tu->consumer); > - tu->flags &= ~flag; > + tu->flags &= file ? ~TP_FLAG_TRACE : ~TP_FLAG_PROFILE; > } > > static int uprobe_event_define_fields(struct ftrace_event_call *event_call) > @@ -867,21 +947,22 @@ 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
