Re: [PATCH] Silly bitmap size accounting fix

[Steven Rostedt]

On Sat, 13 May 2006, Nick Piggin wrote:

> Ingo Molnar wrote:
> > * Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
> >
> >
> >>-#define BITMAP_SIZE ((((MAX_PRIO+1+7)/8)+sizeof(long)-1)/sizeof(long))
> >>+#define BITMAP_SIZE ((((MAX_PRIO+7)/8)+sizeof(long)-1)/sizeof(long))
> >
> >
> > Acked-by: Ingo Molnar <mingo@xxxxxxx>
>
> Really?! What about the delimiter bit set at MAX_PRIO?


		// delimiter for bitsearch
		__set_bit(MAX_PRIO, array->bitmap);


Ah! I see what you mean.  New patch (add a comment).

-- 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 10:09:15.000000000 -0400
@@ -192,6 +192,10 @@ 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.
+ */
 #define BITMAP_SIZE ((((MAX_PRIO+1+7)/8)+sizeof(long)-1)/sizeof(long))

 typedef struct runqueue runqueue_t;
-
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