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Date: Tue, 11 Jun 2024 12:54:40 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: Bart Van Assche <bvanassche@acm.org>
Cc: Dongliang Cui <dongliang.cui@unisoc.com>, axboe@kernel.dk,
 mhiramat@kernel.org, mathieu.desnoyers@efficios.com, ebiggers@kernel.org,
 ke.wang@unisoc.com, hongyu.jin.cn@gmail.com, niuzhiguo84@gmail.com,
 hao_hao.wang@unisoc.com, linux-block@vger.kernel.org,
 linux-kernel@vger.kernel.org, akailash@google.com,
 cuidongliang390@gmail.com
Subject: Re: [PATCH v4] block: Add ioprio to block_rq tracepoint
Message-ID: <20240611125440.6d095270@gandalf.local.home>
In-Reply-To: <86eb3dd0-77a1-4d1d-8e62-38c46bd7563a@acm.org>
References: <20240611073519.323680-1-dongliang.cui@unisoc.com>
	<86eb3dd0-77a1-4d1d-8e62-38c46bd7563a@acm.org>
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On Tue, 11 Jun 2024 09:26:54 -0700
Bart Van Assche <bvanassche@acm.org> wrote:

> On 6/11/24 12:35 AM, Dongliang Cui wrote:
> > +#define IOPRIO_CLASS_STRINGS \
> > +	{ IOPRIO_CLASS_NONE,	"none" }, \
> > +	{ IOPRIO_CLASS_RT,	"rt" }, \
> > +	{ IOPRIO_CLASS_BE,	"be" }, \
> > +	{ IOPRIO_CLASS_IDLE,	"idle" }, \
> > +	{ IOPRIO_CLASS_INVALID,	"invalid"}  
> 
> Shouldn't this array be defined in a C file instead of in a header file?

The way the TRACE_EVENT() macro works, this will not work in a C file.

> -	TP_printk("%d,%d %s (%s) %llu + %u [%d]",
> +	TP_printk("%d,%d %s (%s) %llu + %u %s,%u,%u [%d]",
>  		  MAJOR(__entry->dev), MINOR(__entry->dev),
>  		  __entry->rwbs, __get_str(cmd),
> -		  (unsigned long long)__entry->sector,
> -		  __entry->nr_sector, 0)
> +		  (unsigned long long)__entry->sector, __entry->nr_sector,
> +		  __print_symbolic(IOPRIO_PRIO_CLASS(__entry->ioprio),
> +				   IOPRIO_CLASS_STRINGS),
> +		  IOPRIO_PRIO_HINT(__entry->ioprio),
> +		  IOPRIO_PRIO_LEVEL(__entry->ioprio),  0)
>  );
>  

It's used for __print_symbolic() which the TRACE_EVENT() macro logic (using
header files) will expand it to something useful.

-- Steve