Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752515Ab3F0MNf (ORCPT ); Thu, 27 Jun 2013 08:13:35 -0400 Received: from e9.ny.us.ibm.com ([32.97.182.139]:39223 "EHLO e9.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751916Ab3F0MNe (ORCPT ); Thu, 27 Jun 2013 08:13:34 -0400 Date: Thu, 27 Jun 2013 17:42:31 +0530 From: Srikar Dronamraju To: "zhangwei(Jovi)" Cc: Steven Rostedt , Masami Hiramatsu , Oleg Nesterov , Frederic Weisbecker , Ingo Molnar , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 1/2 v3] tracing/uprobes: Support ftrace_event_file base multibuffer Message-ID: <20130627121231.GB8362@linux.vnet.ibm.com> Reply-To: Srikar Dronamraju References: <51C90ECC.9030303@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <51C90ECC.9030303@huawei.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: No x-cbid: 13062712-7182-0000-0000-0000078BEA7D Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8034 Lines: 265 * zhangwei(Jovi) [2013-06-25 11:30:20]: > 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 degisn. > > 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) > > Signed-off-by: zhangwei(Jovi) > Cc: Masami Hiramatsu > Cc: Frederic Weisbecker > Cc: Oleg Nesterov > Cc: Srikar Dronamraju > --- > kernel/trace/trace_uprobe.c | 118 +++++++++++++++++++++++++++++++++++-------- > 1 file changed, 97 insertions(+), 21 deletions(-) > > diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c > index 32494fb0..dbbb4a9 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 list_head files; > struct trace_uprobe_filter filter; > struct uprobe_consumer consumer; > struct inode *inode; > @@ -65,6 +66,11 @@ struct trace_uprobe { > struct probe_arg args[]; > }; > > +struct event_file_link { > + struct ftrace_event_file *file; > + struct list_head list; > +}; > + > #define SIZEOF_TRACE_UPROBE(n) \ > (offsetof(struct trace_uprobe, args) + \ > (sizeof(struct probe_arg) * (n))) > @@ -124,6 +130,7 @@ 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->files); > tu->consumer.handler = uprobe_dispatcher; > if (is_ret) > tu->consumer.ret_handler = uretprobe_dispatcher; > @@ -511,7 +518,8 @@ 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; > @@ -520,9 +528,12 @@ 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); > + > 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; > > @@ -546,15 +557,28 @@ 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 event_file_link *link; > + > + if (is_ret_probe(tu)) > + return 0; > + > + rcu_read_lock(); > + list_for_each_entry(link, &tu->files, list) > + 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) > + uprobe_trace_print(tu, func, regs, link->file); > + rcu_read_unlock(); > } > > /* Event entry printers */ > @@ -605,33 +629,84 @@ 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; > > + /* we cannot call uprobe_register twice for same tu */ > if (is_trace_uprobe_enabled(tu)) > - return -EINTR; > + enabled = 1; > + > + if (file) { > + struct event_file_link *link; > + > + if (tu->flags & TP_FLAG_PROFILE) > + return -EINTR; > + > + link = kmalloc(sizeof(*link), GFP_KERNEL); > + if (!link) > + return -ENOMEM; > + > + link->file = file; > + list_add_rcu(&link->list, &tu->files); > + > + tu->flags |= TP_FLAG_TRACE; > + } else { > + if (tu->flags & TP_FLAG_TRACE) > + return -EINTR; > + > + 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; Dont we need to free link here? or where does the link that got allocated freed? Think the list of files also needs to be cleaned up. No? > + } > > return ret; > } > > -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) > { > - if (!is_trace_uprobe_enabled(tu)) > - return; > + struct event_file_link *link; > + > + list_for_each_entry(link, &tu->files, list) > + if (link->file == file) > + return link; > + > + return NULL; > +} > + > +static void > +probe_event_disable(struct trace_uprobe *tu, struct ftrace_event_file *file) > +{ > + 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 +942,22 @@ 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 > > -- Thanks and Regards Srikar Dronamraju -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/