From 7be7585393d311866653564fbcd10a3232773c0b Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Sat, 13 Dec 2008 21:20:28 +1030 Subject: [PATCH] cpumask: Use all NR_CPUS bits unless CONFIG_CPUMASK_OFFSTACK Impact: futureproof as we convert more code to new APIs The old cpumask operators treat all NR_CPUS bits as relevent, the new ones use nr_cpumask_bits. For large NR_CPUS and small nr_cpu_ids, this makes a difference. However, mixing the two can cause problems with undefined bits. An arch which sets CONFIG_CPUMASK_OFFSTACK should have converted across to the new operators, so it's safe in that case. (Thanks to Stephen Rothwell for bisecting the initial unused-bits bug, and Mike Travis for this solution). Signed-off-by: Rusty Russell Cc: Mike Travis --- include/linux/cpumask.h | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index 94a2ab88ae85..d4bf52603e6b 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -510,9 +510,6 @@ extern cpumask_t cpu_active_map; [BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD \ } -/* This produces more efficient code. */ -#define nr_cpumask_bits NR_CPUS - #else /* NR_CPUS > BITS_PER_LONG */ #define CPU_BITS_ALL \ @@ -520,10 +517,16 @@ extern cpumask_t cpu_active_map; [0 ... BITS_TO_LONGS(NR_CPUS)-2] = ~0UL, \ [BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD \ } - -#define nr_cpumask_bits nr_cpu_ids #endif /* NR_CPUS > BITS_PER_LONG */ +#ifdef CONFIG_CPUMASK_OFFSTACK +/* Assuming NR_CPUS is huge, a runtime limit is more efficient. Also, + * not all bits may be allocated. */ +#define nr_cpumask_bits nr_cpu_ids +#else +#define nr_cpumask_bits NR_CPUS +#endif + /* verify cpu argument to cpumask_* operators */ static inline unsigned int cpumask_check(unsigned int cpu) {