Re: [PATCH 2/2] mm/page_ref: add tracepoint to track down page reference manipulation

[Joonsoo Kim <js1304-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>]

2016-02-15 14:28 GMT+09:00 Sergey Senozhatsky
<sergey.senozhatsky.work-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>:
> On (02/15/16 14:08), Sergey Senozhatsky wrote:
>>
>> will this compile with !CONFIG_TRACEPOINTS config?
>>

Yes, even if !CONFIG_TRACEPOINTS, it is compiled well.

> uh.. sorry, was composed in email client. seems the correct way to do it is
>
> +#if defined CONFIG_DEBUG_PAGE_REF && defined CONFIG_TRACEPOINTS
>
>  #include <linux/tracepoint-defs.h>
>
>  #define page_ref_tracepoint_active(t) static_key_false(&(t).key)
>
>  extern struct tracepoint __tracepoint_page_ref_set;
>  ...
>
>  extern void __page_ref_set(struct page *page, int v);
>  ...
>
> #else
>
>  #define page_ref_tracepoint_active(t) false
>
>  static inline void __page_ref_set(struct page *page, int v)
>  {
>  }
>  ...
>
> #endif
>
>
>
> or add a dependency of PAGE_REF on CONFIG_TRACEPOINTS in Kconfig.

Thanks for catching it.
I will add "depends on CONFIG_TRACEPOINTS" to Kconfig because
this feature has no meaning if !CONFIG_TRACEPOINTS.


Thanks.