Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755731AbZCVRjZ (ORCPT ); Sun, 22 Mar 2009 13:39:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751360AbZCVRjP (ORCPT ); Sun, 22 Mar 2009 13:39:15 -0400 Received: from fg-out-1718.google.com ([72.14.220.158]:1883 "EHLO fg-out-1718.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750879AbZCVRjO (ORCPT ); Sun, 22 Mar 2009 13:39:14 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; b=EMT583LzkVebX3SAZnTXp9apdJuU0rmTLi4aaKk5W5BVx2VDq/+yyLoYwyM5MFcTt8 qv2fNCiCRjpCufLQvxFpHX9a4dsFnquU83g4iV8XofhVPRrlGK7D9PNTyFQ3hwzljbZ3 KVg4X/GPCcoo56Xt+FLYMmWth1FV0BaDOgCJs= Date: Sun, 22 Mar 2009 18:39:09 +0100 From: Frederic Weisbecker To: Tom Zanussi Cc: linux-kernel , Ingo Molnar , Steven Rostedt Subject: Re: [PATCH 1/4] tracing: add run-time field descriptions for event filtering Message-ID: <20090322173908.GB6002@nowhere> References: <1237710639.7703.46.camel@charm-linux> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1237710639.7703.46.camel@charm-linux> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7121 Lines: 235 Hi Tom, On Sun, Mar 22, 2009 at 03:30:39AM -0500, Tom Zanussi wrote: > This patch makes the field descriptions defined for event tracing > available at run-time, for the event-filtering mechanism introduced in a > subsequent patch. > > The common event fields are prepended with 'common_' in the format > display, allowing them to be distinguished from the other fields that > might internally have same name and can therefore be unambiguously used > in filters. > > Signed-off-by: Tom Zanussi > > --- > kernel/trace/trace.h | 30 ++++++++++++++++------- > kernel/trace/trace_events.c | 40 ++++++++++++++++++++++++++++++- > kernel/trace/trace_events_stage_2.h | 45 +++++++++++++++++++++++++++++++++++ > kernel/trace/trace_events_stage_3.h | 2 + > 4 files changed, 107 insertions(+), 10 deletions(-) > > diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h > index 7cfb741..9288dc7 100644 > --- a/kernel/trace/trace.h > +++ b/kernel/trace/trace.h > @@ -775,16 +775,26 @@ enum { > TRACE_EVENT_TYPE_RAW = 2, > }; > > +struct ftrace_event_field { > + struct list_head link; > + char *name; > + char *type; > + int offset; > + int size; > +}; > + > struct ftrace_event_call { > - char *name; > - char *system; > - struct dentry *dir; > - int enabled; > - int (*regfunc)(void); > - void (*unregfunc)(void); > - int id; > - int (*raw_init)(void); > - int (*show_format)(struct trace_seq *s); > + char *name; > + char *system; > + struct dentry *dir; > + int enabled; > + int (*regfunc)(void); > + void (*unregfunc)(void); > + int id; > + int (*raw_init)(void); > + int (*show_format)(struct trace_seq *s); > + int (*define_fields)(void); > + struct list_head fields; > > #ifdef CONFIG_EVENT_PROFILE > atomic_t profile_count; > @@ -793,6 +803,8 @@ struct ftrace_event_call { > #endif > }; > > +int trace_define_field(struct ftrace_event_call *call, char *type, > + char *name, int offset, int size); > void event_trace_printk(unsigned long ip, const char *fmt, ...); > extern struct ftrace_event_call __start_ftrace_events[]; > extern struct ftrace_event_call __stop_ftrace_events[]; > diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c > index 3047b56..961b057 100644 > --- a/kernel/trace/trace_events.c > +++ b/kernel/trace/trace_events.c > @@ -19,6 +19,34 @@ > > static DEFINE_MUTEX(event_mutex); > > +int trace_define_field(struct ftrace_event_call *call, char *type, > + char *name, int offset, int size) > +{ > + struct ftrace_event_field *field; > + > + field = kmalloc(sizeof(*field), GFP_KERNEL); > + if (!field) > + goto err; > + field->name = kstrdup(name, GFP_KERNEL); > + if (!field->name) > + goto err; > + field->type = kstrdup(type, GFP_KERNEL); > + if (!field->type) > + goto err; > + field->offset = offset; > + field->size = size; > + list_add(&field->link, &call->fields); > + > + return 0; > +err: > + if (field) { > + kfree(field->name); > + kfree(field->type); You need kzalloc to allocate field. With kmalloc, field will point to random filled memory after a fresh allocation. Imagine this path: if (!field->name) goto err; ... err: kfree(field->name) <- field->name = NULL, correct kfree(field->type) <- field->type = ? > + } > + kfree(field); > + return -ENOMEM; > +} > + > static void ftrace_clear_events(void) > { > struct ftrace_event_call *call = (void *)__start_ftrace_events; > @@ -343,7 +371,8 @@ event_enable_write(struct file *filp, const char __user *ubuf, size_t cnt, > > #undef FIELD > #define FIELD(type, name) \ > - #type, #name, offsetof(typeof(field), name), sizeof(field.name) > + #type, "common_" #name, offsetof(typeof(field), name), \ > + sizeof(field.name) > > static int trace_write_header(struct trace_seq *s) > { > @@ -581,6 +610,15 @@ event_create_dir(struct ftrace_event_call *call, struct dentry *d_events) > call->name); > } > > + if (call->define_fields) { > + ret = call->define_fields(); > + if (ret < 0) { > + pr_warning("Could not initialize trace point" > + " events/%s\n", call->name); > + return ret; > + } > + } > + > /* A trace may not want to export its format */ > if (!call->show_format) > return 0; > diff --git a/kernel/trace/trace_events_stage_2.h b/kernel/trace/trace_events_stage_2.h > index 5117c43..30743f7 100644 > --- a/kernel/trace/trace_events_stage_2.h > +++ b/kernel/trace/trace_events_stage_2.h > @@ -129,3 +129,48 @@ ftrace_format_##call(struct trace_seq *s) \ > } > > #include > + > +#undef __field > +#define __field(type, item) \ > + ret = trace_define_field(event_call, #type, #item, \ > + offsetof(typeof(field), item), \ > + sizeof(field.item)); \ > + if (ret) \ > + return ret; > + > +#undef __array > +#define __array(type, item, len) \ > + ret = trace_define_field(event_call, #type "[" #len "]", #item, \ > + offsetof(typeof(field), item), \ > + sizeof(field.item)); \ > + if (ret) \ > + return ret; > + > +#define __common_field(type, item) \ > + ret = trace_define_field(event_call, #type, "common_" #item, \ > + offsetof(typeof(field.ent), item), \ > + sizeof(field.ent.item)); \ > + if (ret) \ > + return ret; > + > +#undef TRACE_EVENT > +#define TRACE_EVENT(call, proto, args, tstruct, func, print) \ > +int \ > +ftrace_define_fields_##call(void) \ > +{ \ > + struct ftrace_raw_##call field; \ > + struct ftrace_event_call *event_call = &event_##call; \ > + int ret; \ > + \ > + __common_field(unsigned char, type); \ > + __common_field(unsigned char, flags); \ > + __common_field(unsigned char, preempt_count); \ > + __common_field(int, pid); \ > + __common_field(int, tgid); \ > + \ > + tstruct; \ > + \ > + return ret; \ > +} > + > +#include > diff --git a/kernel/trace/trace_events_stage_3.h b/kernel/trace/trace_events_stage_3.h > index 6b3261c..468938f 100644 > --- a/kernel/trace/trace_events_stage_3.h > +++ b/kernel/trace/trace_events_stage_3.h > @@ -252,6 +252,7 @@ static int ftrace_raw_init_event_##call(void) \ > if (!id) \ > return -ENODEV; \ > event_##call.id = id; \ > + INIT_LIST_HEAD(&event_##call.fields); \ > return 0; \ > } \ > \ > @@ -264,6 +265,7 @@ __attribute__((section("_ftrace_events"))) event_##call = { \ > .regfunc = ftrace_raw_reg_event_##call, \ > .unregfunc = ftrace_raw_unreg_event_##call, \ > .show_format = ftrace_format_##call, \ > + .define_fields = ftrace_define_fields_##call, \ > _TRACE_PROFILE_INIT(call) \ > } > Other than the small possible memory leak, it looks good. Acked-by: Frederic Weisbecker -- 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/