Re: [PATCH v10 Golden] Unified trace buffer

[Mathieu Desnoyers <compudj@krystal.dyndns.org>]

* Steven Rostedt (rostedt@goodmis.org) wrote:
[...]
> +/*
> + * This hack stolen from mm/slob.c.
> + * We can store per page timing information in the page frame of the page.
> + * Thanks to Peter Zijlstra for suggesting this idea.
> + */
> +struct buffer_page {
> +	union {
> +		struct {
> +			unsigned long	 flags;		/* mandatory */
> +			atomic_t	 _count;	/* mandatory */
> +			u64		 time_stamp;	/* page time stamp */
> +			unsigned	 size;		/* size of page data */
> +			struct list_head list;		/* list of free pages */
> +		};
> +		struct page page;
> +	};
> +};
> +

Hi Steven,

You should have a look at mm/slob.c free_slob_page(). I think your page
free will generate a "bad_page" call due to mapping != NULL and mapcount
!= 0. I just ran into this in my own code. :)

Regards,

Mathieu

-- 
Mathieu Desnoyers
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