From 64b47e8fdb40a0d46e8cf458dd3e24f8afa073f6 Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Mon, 7 Apr 2014 15:39:45 -0700 Subject: lglock: map to spinlock when !CONFIG_SMP When the system has only one CPU, lglock is effectively a spinlock; map it directly to spinlock to eliminate the indirection and duplicate code. In addition to removing overhead, this drops 1.6k of code with a defconfig modified to have !CONFIG_SMP, and 1.1k with a minimal config. Signed-off-by: Josh Triplett Cc: Rusty Russell Cc: Michal Marek Cc: Thomas Gleixner Cc: David Howells Cc: "H. Peter Anvin" Cc: Nick Piggin Cc: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/lglock.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'include/linux/lglock.h') diff --git a/include/linux/lglock.h b/include/linux/lglock.h index 96549abe8842..0081f000e34b 100644 --- a/include/linux/lglock.h +++ b/include/linux/lglock.h @@ -25,6 +25,8 @@ #include #include +#ifdef CONFIG_SMP + #ifdef CONFIG_DEBUG_LOCK_ALLOC #define LOCKDEP_INIT_MAP lockdep_init_map #else @@ -57,4 +59,18 @@ void lg_local_unlock_cpu(struct lglock *lg, int cpu); void lg_global_lock(struct lglock *lg); void lg_global_unlock(struct lglock *lg); +#else +/* When !CONFIG_SMP, map lglock to spinlock */ +#define lglock spinlock +#define DEFINE_LGLOCK(name) DEFINE_SPINLOCK(name) +#define DEFINE_STATIC_LGLOCK(name) static DEFINE_SPINLOCK(name) +#define lg_lock_init(lg, name) spin_lock_init(lg) +#define lg_local_lock spin_lock +#define lg_local_unlock spin_unlock +#define lg_local_lock_cpu(lg, cpu) spin_lock(lg) +#define lg_local_unlock_cpu(lg, cpu) spin_unlock(lg) +#define lg_global_lock spin_lock +#define lg_global_unlock spin_unlock +#endif + #endif -- cgit v1.2.3