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Message-ID: <43b10ad23a80ee5ae9f10b6d47d7944b6b14a25d.camel@kernel.org>
Subject: Re: [PATCH v3 1/2] tracing: support "bool" type in synthetic trace
 events
From:   Tom Zanussi <zanussi@kernel.org>
To:     Steven Rostedt <rostedt@goodmis.org>,
        Axel Rasmussen <axelrasmussen@google.com>
Cc:     Ingo Molnar <mingo@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Michel Lespinasse <walken@google.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Daniel Jordan <daniel.m.jordan@oracle.com>,
        Laurent Dufour <ldufour@linux.ibm.com>,
        Jann Horn <jannh@google.com>,
        Chinwen Chang <chinwen.chang@mediatek.com>,
        Yafang Shao <laoar.shao@gmail.com>,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
Date:   Mon, 12 Oct 2020 09:26:13 -0500
In-Reply-To: <20201012101527.6df53dda@gandalf.local.home>
References: <20201009220524.485102-1-axelrasmussen@google.com>
         <20201009220524.485102-2-axelrasmussen@google.com>
         <20201012101527.6df53dda@gandalf.local.home>
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Hi Steve,

Looks ok to me.

Acked-by: Tom Zanussi <zanussi@kernel.org>

Thanks,

Tom


On Mon, 2020-10-12 at 10:15 -0400, Steven Rostedt wrote:
> Tom,
> 
> Can you ack this patch for me?
> 
> -- Steve
> 
> 
> On Fri,  9 Oct 2020 15:05:23 -0700
> Axel Rasmussen <axelrasmussen@google.com> wrote:
> 
> > It's common [1] to define tracepoint fields as "bool" when they
> > contain
> > a true / false value. Currently, defining a synthetic event with a
> > "bool" field yields EINVAL. It's possible to work around this by
> > using
> > e.g. u8 (assuming sizeof(bool) is 1, and bool is unsigned; if
> > either of
> > these properties don't match, you get EINVAL [2]).
> > 
> > Supporting "bool" explicitly makes hooking this up easier and more
> > portable for userspace.
> > 
> > [1]: grep -r "bool" include/trace/events/
> > [2]: check_synth_field() in kernel/trace/trace_events_hist.c
> > 
> > Acked-by: Michel Lespinasse <walken@google.com>
> > Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
> > ---
> >  kernel/trace/trace_events_synth.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/kernel/trace/trace_events_synth.c
> > b/kernel/trace/trace_events_synth.c
> > index 8e1974fbad0e..8f94c84349a6 100644
> > --- a/kernel/trace/trace_events_synth.c
> > +++ b/kernel/trace/trace_events_synth.c
> > @@ -234,6 +234,8 @@ static int synth_field_size(char *type)
> >  		size = sizeof(long);
> >  	else if (strcmp(type, "unsigned long") == 0)
> >  		size = sizeof(unsigned long);
> > +	else if (strcmp(type, "bool") == 0)
> > +		size = sizeof(bool);
> >  	else if (strcmp(type, "pid_t") == 0)
> >  		size = sizeof(pid_t);
> >  	else if (strcmp(type, "gfp_t") == 0)
> > @@ -276,6 +278,8 @@ static const char *synth_field_fmt(char *type)
> >  		fmt = "%ld";
> >  	else if (strcmp(type, "unsigned long") == 0)
> >  		fmt = "%lu";
> > +	else if (strcmp(type, "bool") == 0)
> > +		fmt = "%d";
> >  	else if (strcmp(type, "pid_t") == 0)
> >  		fmt = "%d";
> >  	else if (strcmp(type, "gfp_t") == 0)
> > --
> > 2.28.0.1011.ga647a8990f-goog
> 
>