Re: [PATCH] Silly bitmap size accounting fix

[Steven Rostedt]

> > +/*
> > + * 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?

-- Steve

Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>

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;
-
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