We can use ilog2() to more easily produce the desired NR_BG_LOCKS. This
works because ilog2() is evaluated at compile-time when its argument is
a compile-time constant.
I did not change the chosen NR_BG_LOCKS values.
Signed-off-by: Eric Biggers <ebigg...@google.com>
---
include/linux/blockgroup_lock.h | 22 ++--------------------
1 file changed, 2 insertions(+), 20 deletions(-)
diff --git a/include/linux/blockgroup_lock.h b/include/linux/blockgroup_lock.h
index 61b583d..225bdb7 100644
--- a/include/linux/blockgroup_lock.h
+++ b/include/linux/blockgroup_lock.h
@@ -10,28 +10,10 @@
#include <linux/cache.h>
#ifdef CONFIG_SMP
-
-/*
- * We want a power-of-two. Is there a better way than this?
- */
-
-#if NR_CPUS >= 32
-#define NR_BG_LOCKS 128
-#elif NR_CPUS >= 16
-#define NR_BG_LOCKS 64
-#elif NR_CPUS >= 8
-#define NR_BG_LOCKS 32
-#elif NR_CPUS >= 4
-#define NR_BG_LOCKS 16
-#elif NR_CPUS >= 2
-#define NR_BG_LOCKS 8
+#define NR_BG_LOCKS (4 << ilog2(NR_CPUS < 32 ? NR_CPUS : 32))
#else
-#define NR_BG_LOCKS 4
-#endif
-
-#else /* CONFIG_SMP */
#define NR_BG_LOCKS 1
-#endif /* CONFIG_SMP */
+#endif
struct bgl_lock {
spinlock_t lock;
--
2.8.0.rc3.226.g39d4020
