From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754429Ab0HQM6A (ORCPT ); Tue, 17 Aug 2010 08:58:00 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:61277 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753129Ab0HQM57 (ORCPT ); Tue, 17 Aug 2010 08:57:59 -0400 X-Authority-Analysis: v=1.1 cv=mWMe3HXt1P3ELXxrmMgI9QKdSRnwjSxQbBh3ay0KAh4= c=1 sm=0 a=c1PsnirsPswA:10 a=Q9fys5e9bTEA:10 a=IXo+6rlC6z1XzBFn1RNpIA==:17 a=omOdbC7AAAAA:8 a=FVIerGIqPrdJkPS56NEA:9 a=GTC0x3jP4mdD5oxznWUA:7 a=_HIJCkXGof81LGDVwIc8sxloKcUA:4 a=PUjeQqilurYA:10 a=IXo+6rlC6z1XzBFn1RNpIA==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.87.39 Subject: Re: [PATCH] tracing: Simplify seqfile code for format file From: Steven Rostedt To: Li Zefan Cc: Frederic Weisbecker , Ingo Molnar , LKML In-Reply-To: <4C6A23C2.9020606@cn.fujitsu.com> References: <4C6A23C2.9020606@cn.fujitsu.com> Content-Type: text/plain; charset="ISO-8859-15" Date: Tue, 17 Aug 2010 08:57:56 -0400 Message-ID: <1282049876.3268.1292.camel@gandalf.stny.rr.com> Mime-Version: 1.0 X-Mailer: Evolution 2.30.2 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2010-08-17 at 13:53 +0800, Li Zefan wrote: > We don't have to use the trick that marks a pointer's LSB to > distinguish event fields from common fields. > Hehe, you don't like tricks. I find it as a certain art to the magic of programming ;-) > Signed-off-by: Li Zefan I'll pull this in and see if we can get this into 2.6.36 too. Thanks! -- Steve > --- > kernel/trace/trace_events.c | 55 ++++++++++++++----------------------------- > 1 files changed, 18 insertions(+), 37 deletions(-) > > diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c > index 4c758f1..398c0e8 100644 > --- a/kernel/trace/trace_events.c > +++ b/kernel/trace/trace_events.c > @@ -600,21 +600,29 @@ out: > > enum { > FORMAT_HEADER = 1, > - FORMAT_PRINTFMT = 2, > + FORMAT_FIELD_SEPERATOR = 2, > + FORMAT_PRINTFMT = 3, > }; > > static void *f_next(struct seq_file *m, void *v, loff_t *pos) > { > struct ftrace_event_call *call = m->private; > struct ftrace_event_field *field; > - struct list_head *head; > + struct list_head *common_head = &ftrace_common_fields; > + struct list_head *head = trace_get_fields(call); > > (*pos)++; > > switch ((unsigned long)v) { > case FORMAT_HEADER: > - head = &ftrace_common_fields; > + if (unlikely(list_empty(common_head))) > + return NULL; > + > + field = list_entry(common_head->prev, > + struct ftrace_event_field, link); > + return field; > > + case FORMAT_FIELD_SEPERATOR: > if (unlikely(list_empty(head))) > return NULL; > > @@ -626,31 +634,10 @@ static void *f_next(struct seq_file *m, void *v, loff_t *pos) > return NULL; > } > > - head = trace_get_fields(call); > - > - /* > - * To separate common fields from event fields, the > - * LSB is set on the first event field. Clear it in case. > - */ > - v = (void *)((unsigned long)v & ~1L); > - > field = v; > - /* > - * If this is a common field, and at the end of the list, then > - * continue with main list. > - */ > - if (field->link.prev == &ftrace_common_fields) { > - if (unlikely(list_empty(head))) > - return NULL; > - field = list_entry(head->prev, struct ftrace_event_field, link); > - /* Set the LSB to notify f_show to print an extra newline */ > - field = (struct ftrace_event_field *) > - ((unsigned long)field | 1); > - return field; > - } > - > - /* If we are done tell f_show to print the format */ > - if (field->link.prev == head) > + if (field->link.prev == common_head) > + return (void *)FORMAT_FIELD_SEPERATOR; > + else if (field->link.prev == head) > return (void *)FORMAT_PRINTFMT; > > field = list_entry(field->link.prev, struct ftrace_event_field, link); > @@ -688,22 +675,16 @@ static int f_show(struct seq_file *m, void *v) > seq_printf(m, "format:\n"); > return 0; > > + case FORMAT_FIELD_SEPERATOR: > + seq_putc(m, '\n'); > + return 0; > + > case FORMAT_PRINTFMT: > seq_printf(m, "\nprint fmt: %s\n", > call->print_fmt); > return 0; > } > > - /* > - * To separate common fields from event fields, the > - * LSB is set on the first event field. Clear it and > - * print a newline if it is set. > - */ > - if ((unsigned long)v & 1) { > - seq_putc(m, '\n'); > - v = (void *)((unsigned long)v & ~1L); > - } > - > field = v; > > /*