Messages in this thread Patch in this message | | | From | guoren@kernel ... | Subject | [PATCH V7 4/5] asm-generic: spinlock: Add combo spinlock (ticket & queued) | Date | Tue, 28 Jun 2022 04:17:06 -0400 |
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From: Guo Ren <guoren@linux.alibaba.com>
Some architecture has a flexible requirement on the type of spinlock. Some LL/SC architectures of ISA don't force micro-arch to give a strong forward guarantee. Thus different kinds of memory model micro-arch would come out in one ISA. The ticket lock is suitable for exclusive monitor designed LL/SC micro-arch with limited cores and "!NUMA". The queue-spinlock could deal with NUMA/large-scale scenarios with a strong forward guarantee designed LL/SC micro-arch.
So, make the spinlock a combo with feature.
Signed-off-by: Guo Ren <guoren@linux.alibaba.com> Signed-off-by: Guo Ren <guoren@kernel.org> Cc: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Palmer Dabbelt <palmer@rivosinc.com> --- include/asm-generic/spinlock.h | 43 ++++++++++++++++++++++++++++++++-- kernel/locking/qspinlock.c | 2 ++ 2 files changed, 43 insertions(+), 2 deletions(-)
diff --git a/include/asm-generic/spinlock.h b/include/asm-generic/spinlock.h index f41dc7c2b900..a9b43089bf99 100644 --- a/include/asm-generic/spinlock.h +++ b/include/asm-generic/spinlock.h @@ -28,34 +28,73 @@ #define __ASM_GENERIC_SPINLOCK_H #include <asm-generic/ticket_spinlock.h> +#ifdef CONFIG_ARCH_USE_QUEUED_SPINLOCKS +#include <linux/jump_label.h> +#include <asm-generic/qspinlock.h> + +DECLARE_STATIC_KEY_TRUE(use_qspinlock_key); +#endif + +#undef arch_spin_is_locked +#undef arch_spin_is_contended +#undef arch_spin_value_unlocked +#undef arch_spin_lock +#undef arch_spin_trylock +#undef arch_spin_unlock static __always_inline void arch_spin_lock(arch_spinlock_t *lock) { - ticket_spin_lock(lock); +#ifdef CONFIG_ARCH_USE_QUEUED_SPINLOCKS + if (static_branch_likely(&use_qspinlock_key)) + queued_spin_lock(lock); + else +#endif + ticket_spin_lock(lock); } static __always_inline bool arch_spin_trylock(arch_spinlock_t *lock) { +#ifdef CONFIG_ARCH_USE_QUEUED_SPINLOCKS + if (static_branch_likely(&use_qspinlock_key)) + return queued_spin_trylock(lock); +#endif return ticket_spin_trylock(lock); } static __always_inline void arch_spin_unlock(arch_spinlock_t *lock) { - ticket_spin_unlock(lock); +#ifdef CONFIG_ARCH_USE_QUEUED_SPINLOCKS + if (static_branch_likely(&use_qspinlock_key)) + queued_spin_unlock(lock); + else +#endif + ticket_spin_unlock(lock); } static __always_inline int arch_spin_is_locked(arch_spinlock_t *lock) { +#ifdef CONFIG_ARCH_USE_QUEUED_SPINLOCKS + if (static_branch_likely(&use_qspinlock_key)) + return queued_spin_is_locked(lock); +#endif return ticket_spin_is_locked(lock); } static __always_inline int arch_spin_is_contended(arch_spinlock_t *lock) { +#ifdef CONFIG_ARCH_USE_QUEUED_SPINLOCKS + if (static_branch_likely(&use_qspinlock_key)) + return queued_spin_is_contended(lock); +#endif return ticket_spin_is_contended(lock); } static __always_inline int arch_spin_value_unlocked(arch_spinlock_t lock) { +#ifdef CONFIG_ARCH_USE_QUEUED_SPINLOCKS + if (static_branch_likely(&use_qspinlock_key)) + return queued_spin_value_unlocked(lock); +#endif return ticket_spin_value_unlocked(lock); } diff --git a/kernel/locking/qspinlock.c b/kernel/locking/qspinlock.c index 65a9a10caa6f..b7f7436f42f6 100644 --- a/kernel/locking/qspinlock.c +++ b/kernel/locking/qspinlock.c @@ -566,6 +566,8 @@ void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val) } EXPORT_SYMBOL(queued_spin_lock_slowpath); +DEFINE_STATIC_KEY_TRUE_RO(use_qspinlock_key); + /* * Generate the paravirt code for queued_spin_unlock_slowpath(). */ -- 2.36.1
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