Re: [PATCH 2/2] sched: fix cpupri priocount
From: Peter Zijlstra <peterz@infradead.org>
Date: 2008-06-04 21:09:52
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On Wed, 2008-06-04 at 15:04 -0400, Gregory Haskins wrote:
quoted hunk ↗ jump to hunk
A rounding error was pointed out by Peter Zijlstra which would result in the structure holding priorities to be off by one. Signed-off-by: Gregory Haskins <redacted> CC: Peter Zijlstra <peterz@infradead.org> --- kernel/sched_cpupri.h | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-)diff --git a/kernel/sched_cpupri.h b/kernel/sched_cpupri.h index 16d29b9..817c55c 100644 --- a/kernel/sched_cpupri.h +++ b/kernel/sched_cpupri.h@@ -4,7 +4,7 @@ #include <linux/sched.h> #define CPUPRI_NR_PRIORITIES 2+MAX_RT_PRIO -#define CPUPRI_NR_PRI_WORDS CPUPRI_NR_PRIORITIES/BITS_PER_LONG +#define CPUPRI_NR_PRI_WORDS (CPUPRI_NR_PRIORITIES + BITS_PER_LONG/2)/BITS_PER_LONG
(33 + 16) / 32 = 49 / 32 = 1 So its still wrong ;-) Please use DECLARE_BITMAP and or BITS_TO_LONGS to avoid these issues.