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Date:   Wed, 27 Mar 2019 09:24:22 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Huang Shijie <sjhuang@iluvatar.ai>
Cc:     <mingo@redhat.com>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] trace/page_ref: print out the page migratetype name
Message-ID: <20190327092422.3cf2c7a3@gandalf.local.home>
In-Reply-To: <20190327050937.5395-1-sjhuang@iluvatar.ai>
References: <20190327050937.5395-1-sjhuang@iluvatar.ai>
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On Wed, 27 Mar 2019 13:09:37 +0800
Huang Shijie <sjhuang@iluvatar.ai> wrote:

> Print out the page migratetype name which is more readable.

Except that it breaks perf and trace-cmd, as they wont know what a
migratetype_names array contains.

See how writeback does it. Which would be something like this for you.

/* enums need to be exported to user space */
#undef EM
#undef EMe
#undef EM_CMA
#undef EM_ISOLATE
#define EM(a)	 	TRACE_DEFINE_ENUM(MIGRATE_##a);
#define EMe(a)		TRACE_DEFINE_ENUM(MIGRATE_##a);

#ifdef CONFIG_CMA
# define EM_CMA		TRACE_DEFINE_ENUM(MIGRATE_CMA);
#else
# define EM_CMA
#endif

#ifdef CONFIG_MEMORY_ISOLATION
# define EM_ISOLATE	TRACE_DEFINE_ENUM(MIGRATE_ISOLATION);
#else
# define EM_ISOLATE
#endif

#define MIGRATE_ENUM_TYPES	\
	EM(UNMOVABLE)		\
	EM(MOVABLE)		\
	EM(RECLAIMABLE)		\
	EM(PCPTYPES)		\
	EM(HIGHATOMIC)		\
	EM_CMA			\
	EM_ISOLATE		\
	EMe(TYPES)

MIGRATE_ENUM_TYPES

#undef EM
#undef EMe
#undef EM_CMA
#undef EM_ISOLATE
#define EM(a)		{ MIGRATE_##a, #a },
#define EMe(a)		{ MIGRATE_##a, #a }

#ifdef CONFIG_CMA
# define EM_CMA		{ MIGRATE_CMA, "CMA" },
#else
# define EM_CMA
#endif

#ifdef CONFIG_MEMORY_ISOLATION
# define EM_ISOLATE	{ MIGRATE_ISOLATION, "ISOLATION" }
#else
# define EM_ISOLATE
#endif

> 
> Signed-off-by: Huang Shijie <sjhuang@iluvatar.ai>
> ---
>  include/trace/events/page_ref.h | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/include/trace/events/page_ref.h b/include/trace/events/page_ref.h
> index 5d2ea93956ce..94df979c2d6b 100644
> --- a/include/trace/events/page_ref.h
> +++ b/include/trace/events/page_ref.h
> @@ -36,11 +36,12 @@ DECLARE_EVENT_CLASS(page_ref_mod_template,
>  		__entry->val = v;
>  	),
>  
> -	TP_printk("pfn=0x%lx flags=%s count=%d mapcount=%d mapping=%p mt=%d val=%d",
> +	TP_printk("pfn=0x%lx flags=%s count=%d mapcount=%d mapping=%p mt=%s val=%d",
>  		__entry->pfn,
>  		show_page_flags(__entry->flags & ((1UL << NR_PAGEFLAGS) - 1)),
>  		__entry->count,
> -		__entry->mapcount, __entry->mapping, __entry->mt,
> +		__entry->mapcount, __entry->mapping,
> +		migratetype_names[__entry->mt],

Then here you add:

		print_symbolic(__entry->mt, MIGRATE_ENUM_TYPES),

>  		__entry->val)
>  );
>  
> @@ -86,11 +87,12 @@ DECLARE_EVENT_CLASS(page_ref_mod_and_test_template,
>  		__entry->ret = ret;
>  	),
>  
> -	TP_printk("pfn=0x%lx flags=%s count=%d mapcount=%d mapping=%p mt=%d val=%d ret=%d",
> +	TP_printk("pfn=0x%lx flags=%s count=%d mapcount=%d mapping=%p mt=%s val=%d ret=%d",
>  		__entry->pfn,
>  		show_page_flags(__entry->flags & ((1UL << NR_PAGEFLAGS) - 1)),
>  		__entry->count,
> -		__entry->mapcount, __entry->mapping, __entry->mt,
> +		__entry->mapcount, __entry->mapping,
> +		migratetype_names[__entry->mt],
>  		__entry->val, __entry->ret)
>  );
>