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SubjectRe: [PATCH] Silly bitmap size accounting fix
Steven Rostedt wrote:
>
>>>+/*
>>>+ * Calculate BITMAP_SIZE.
>>>+ * The bitmask holds MAX_PRIO bits + 1 for the delimiter.
>>
>>+ * Calculation is to find the minimum number of longs that holds MAX_PRIO+1 bits:
>>+ * size-in-chars = ceiling((MAX_PRIO+1) / CHAR_BITS)
>>+ * size-in-longs = ceiling(size-in-chars / sizeof(long))
>>
>>
>>>+ */
>>> #define BITMAP_SIZE ((((MAX_PRIO+1+7)/8)+sizeof(long)-1)/sizeof(long))
>>>
>>
>
> What do you think of the following comment, better?

Cool, thanks.

>
> -- Steve
>
> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
>
> Index: linux-2.6.17-rc3-mm1/kernel/sched.c
> ===================================================================
> --- linux-2.6.17-rc3-mm1.orig/kernel/sched.c 2006-05-12 04:02:32.000000000 -0400
> +++ linux-2.6.17-rc3-mm1/kernel/sched.c 2006-05-13 10:50:44.000000000 -0400
> @@ -192,6 +192,13 @@ static inline unsigned int task_timeslic
> * These are the runqueue data structures:
> */
>
> +/*
> + * Calculate BITMAP_SIZE.
> + * The bitmask holds MAX_PRIO bits + 1 for the delimiter.
> + * BITMAP_SIZE is the minimum number of longs that holds MAX_PRIO+1 bits:
> + * size-in-bytes = ceiling((MAX_PRIO+1) / BITS_PER_BYTE)
> + * size-in-longs = ceiling(size-in-bytes / sizeof(long))
> + */
> #define BITMAP_SIZE ((((MAX_PRIO+1+7)/8)+sizeof(long)-1)/sizeof(long))
>
> typedef struct runqueue runqueue_t;
>


--
SUSE Labs, Novell Inc.
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