Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755001Ab3GATWQ (ORCPT ); Mon, 1 Jul 2013 15:22:16 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:30482 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752294Ab3GATWP (ORCPT ); Mon, 1 Jul 2013 15:22:15 -0400 X-Authority-Analysis: v=2.0 cv=Odoa/2vY c=1 sm=0 a=Sro2XwOs0tJUSHxCKfOySw==:17 a=Drc5e87SC40A:10 a=b50BksreE0kA:10 a=5SG0PmZfjMsA:10 a=IkcTkHD0fZMA:10 a=meVymXHHAAAA:8 a=KGjhK52YXX0A:10 a=R4sMS_rjWVkA:10 a=i0EeH86SAAAA:8 a=3nbZYyFuAAAA:8 a=pGLkceISAAAA:8 a=20KFwNOVAAAA:8 a=VnNF1IyMAAAA:8 a=rxTo8IrRAAAA:8 a=xmjMVpMzI-pPJyG_v48A:9 a=QEXdDO2ut3YA:10 a=xYdMApT76mEA:10 a=hPjdaMEvmhQA:10 a=EvKJbDF4Ut8A:10 a=MSl-tDqOz04A:10 a=jEp0ucaQiEUA:10 a=Sro2XwOs0tJUSHxCKfOySw==:117 X-Cloudmark-Score: 0 X-Authenticated-User: X-Originating-IP: 67.255.60.225 Message-ID: <1372706533.22688.15.camel@gandalf.local.home> Subject: Re: [PATCH v4] tracing/uprobes: Support ftrace_event_file base multibuffer From: Steven Rostedt To: "zhangwei(Jovi)" Cc: Masami Hiramatsu , Oleg Nesterov , Srikar Dronamraju , Frederic Weisbecker , Ingo Molnar , "linux-kernel@vger.kernel.org" Date: Mon, 01 Jul 2013 15:22:13 -0400 In-Reply-To: <51CE920C.5020001@huawei.com> References: <51CE920C.5020001@huawei.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.4.4-3 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8390 Lines: 274 On Sat, 2013-06-29 at 15:51 +0800, zhangwei(Jovi) wrote: > [v3->v4]: > 1. use "bool enabled = is_trace_uprobe_enabled(tu);", suggested by Oleg. > 2. use list_add_tail_rcu instead of list_add_rcu, suggested by Masami. > 3. fix the error handling in probe_event_enable, found by Srikar. Is this the final patch? Masami, can you give your reviewed by (Oleg and Srikar, feel free to add your tags either). Also, the origin was a two patch set. Is the second patch needed? Thanks, -- Steve > > ------------------- > > 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 | 123 +++++++++++++++++++++++++++++++++++-------- > 1 file changed, 101 insertions(+), 22 deletions(-) > > diff --git a/kernel/trace/trace_uprobe.c b/kernel/trace/trace_uprobe.c > index 32494fb0..760d4ed 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 +629,87 @@ 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) > { > + bool enabled = is_trace_uprobe_enabled(tu); > + struct event_file_link *link; > int ret = 0; > > - if (is_trace_uprobe_enabled(tu)) > - return -EINTR; > + if (file) { > + if (tu->flags & TP_FLAG_PROFILE) > + return -EINTR; > + > + link = kmalloc(sizeof(*link), GFP_KERNEL); > + if (!link) > + return -ENOMEM; > + > + link->file = file; > + list_add_tail_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; > + /* we cannot call uprobe_register twice for same tu */ > + if (!enabled) { > + tu->consumer.filter = filter; > + ret = uprobe_register(tu->inode, tu->offset, &tu->consumer); > + } > + > + if (ret) { > + if (file) { > + list_del_rcu(&link->list); > + kfree(link); > + tu->flags &= ~TP_FLAG_TRACE; > + } else > + tu->flags &= ~TP_FLAG_PROFILE; > + } > > 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 +945,22 @@ 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: -- 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/