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| author | Rusty Russell <rusty@rustcorp.com.au> | 2008-12-13 21:20:28 +1030 |
|---|---|---|
| committer | Rusty Russell <rusty@rustcorp.com.au> | 2008-12-13 21:20:28 +1030 |
| commit | 7be7585393d311866653564fbcd10a3232773c0b (patch) | |
| tree | 50399f8f3bd97d521f91bf2de30dd41c081e3321 | |
| parent | f0b848ce6fe9062d504d997e9e97fe0f87d57217 (diff) | |
| download | lwn-7be7585393d311866653564fbcd10a3232773c0b.tar.gz lwn-7be7585393d311866653564fbcd10a3232773c0b.zip | |
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 <rusty@rustcorp.com.au>
Cc: Mike Travis <travis@sgi.com>
| -rw-r--r-- | include/linux/cpumask.h | 11 |
1 files changed, 7 insertions, 4 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 \ @@ -520,9 +517,15 @@ extern cpumask_t cpu_active_map; [0 ... BITS_TO_LONGS(NR_CPUS)-2] = ~0UL, \ [BITS_TO_LONGS(NR_CPUS)-1] = CPU_MASK_LAST_WORD \ } +#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 -#endif /* NR_CPUS > BITS_PER_LONG */ +#else +#define nr_cpumask_bits NR_CPUS +#endif /* verify cpu argument to cpumask_* operators */ static inline unsigned int cpumask_check(unsigned int cpu) |