Commit-ID: 41946c86876ea6a3e8857182356e6d76dbfe7fb6 Gitweb: http://git.kernel.org/tip/41946c86876ea6a3e8857182356e6d76dbfe7fb6 Author: Pan Xinhui <[email protected]> AuthorDate: Wed, 2 Nov 2016 05:08:31 -0400 Committer: Ingo Molnar <[email protected]> CommitDate: Tue, 22 Nov 2016 12:48:06 +0100
locking/core, powerpc: Implement vcpu_is_preempted(cpu) Optimize spinlock and mutex busy-loops by providing a vcpu_is_preempted(cpu) function on pSeries. We do not support PowerNV. All this can be achieved by using lppaca->yield_count, which is zero on PowerNV. Suggested-by: Boqun Feng <[email protected]> Suggested-by: Peter Zijlstra (Intel) <[email protected]> Signed-off-by: Pan Xinhui <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Cc: [email protected] Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Cc: [email protected] Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]> --- arch/powerpc/include/asm/spinlock.h | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h index fa37fe9..8c1b913 100644 --- a/arch/powerpc/include/asm/spinlock.h +++ b/arch/powerpc/include/asm/spinlock.h @@ -52,6 +52,14 @@ #define SYNC_IO #endif +#ifdef CONFIG_PPC_PSERIES +#define vcpu_is_preempted vcpu_is_preempted +static inline bool vcpu_is_preempted(int cpu) +{ + return !!(be32_to_cpu(lppaca_of(cpu).yield_count) & 1); +} +#endif + static __always_inline int arch_spin_value_unlocked(arch_spinlock_t lock) { return lock.slock == 0;
