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authorRusty Russell <rusty@rustcorp.com.au>2008-12-13 21:20:28 +1030
committerRusty Russell <rusty@rustcorp.com.au>2008-12-13 21:20:28 +1030
commit7be7585393d311866653564fbcd10a3232773c0b (patch)
tree50399f8f3bd97d521f91bf2de30dd41c081e3321 /include/linux/cpumask.h
parentf0b848ce6fe9062d504d997e9e97fe0f87d57217 (diff)
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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>
Diffstat (limited to 'include/linux/cpumask.h')
-rw-r--r--include/linux/cpumask.h11
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)