diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2014-10-13 15:51:40 +0200 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2014-10-13 15:51:40 +0200 |
commit | 6d5f0ebfc0be9cbfeaafdd9258d5fa24b7975a36 (patch) | |
tree | 3b7a5851a3d9f02441e2dcbaf22785d131544544 /arch/x86 | |
parent | dbb885fecc1b1b35e93416bedd24d21bd20f60ed (diff) | |
parent | 8acd91e8620836a56ff62028ed28ba629f2881a0 (diff) |
Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull core locking updates from Ingo Molnar:
"The main updates in this cycle were:
- mutex MCS refactoring finishing touches: improve comments, refactor
and clean up code, reduce debug data structure footprint, etc.
- qrwlock finishing touches: remove old code, self-test updates.
- small rwsem optimization
- various smaller fixes/cleanups"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/lockdep: Revert qrwlock recusive stuff
locking/rwsem: Avoid double checking before try acquiring write lock
locking/rwsem: Move EXPORT_SYMBOL() lines to follow function definition
locking/rwlock, x86: Delete unused asm/rwlock.h and rwlock.S
locking/rwlock, x86: Clean up asm/spinlock*.h to remove old rwlock code
locking/semaphore: Resolve some shadow warnings
locking/selftest: Support queued rwlock
locking/lockdep: Restrict the use of recursive read_lock() with qrwlock
locking/spinlocks: Always evaluate the second argument of spin_lock_nested()
locking/Documentation: Update locking/mutex-design.txt disadvantages
locking/Documentation: Move locking related docs into Documentation/locking/
locking/mutexes: Use MUTEX_SPIN_ON_OWNER when appropriate
locking/mutexes: Refactor optimistic spinning code
locking/mcs: Remove obsolete comment
locking/mutexes: Document quick lock release when unlocking
locking/mutexes: Standardize arguments in lock/unlock slowpaths
locking: Remove deprecated smp_mb__() barriers
Diffstat (limited to 'arch/x86')
-rw-r--r-- | arch/x86/include/asm/rwlock.h | 49 | ||||
-rw-r--r-- | arch/x86/include/asm/spinlock.h | 81 | ||||
-rw-r--r-- | arch/x86/include/asm/spinlock_types.h | 4 | ||||
-rw-r--r-- | arch/x86/lib/Makefile | 1 | ||||
-rw-r--r-- | arch/x86/lib/rwlock.S | 44 |
5 files changed, 2 insertions, 177 deletions
diff --git a/arch/x86/include/asm/rwlock.h b/arch/x86/include/asm/rwlock.h deleted file mode 100644 index a5370a03d90..00000000000 --- a/arch/x86/include/asm/rwlock.h +++ /dev/null @@ -1,49 +0,0 @@ -#ifndef _ASM_X86_RWLOCK_H -#define _ASM_X86_RWLOCK_H - -#include <asm/asm.h> - -#if CONFIG_NR_CPUS <= 2048 - -#ifndef __ASSEMBLY__ -typedef union { - s32 lock; - s32 write; -} arch_rwlock_t; -#endif - -#define RW_LOCK_BIAS 0x00100000 -#define READ_LOCK_SIZE(insn) __ASM_FORM(insn##l) -#define READ_LOCK_ATOMIC(n) atomic_##n -#define WRITE_LOCK_ADD(n) __ASM_FORM_COMMA(addl n) -#define WRITE_LOCK_SUB(n) __ASM_FORM_COMMA(subl n) -#define WRITE_LOCK_CMP RW_LOCK_BIAS - -#else /* CONFIG_NR_CPUS > 2048 */ - -#include <linux/const.h> - -#ifndef __ASSEMBLY__ -typedef union { - s64 lock; - struct { - u32 read; - s32 write; - }; -} arch_rwlock_t; -#endif - -#define RW_LOCK_BIAS (_AC(1,L) << 32) -#define READ_LOCK_SIZE(insn) __ASM_FORM(insn##q) -#define READ_LOCK_ATOMIC(n) atomic64_##n -#define WRITE_LOCK_ADD(n) __ASM_FORM(incl) -#define WRITE_LOCK_SUB(n) __ASM_FORM(decl) -#define WRITE_LOCK_CMP 1 - -#endif /* CONFIG_NR_CPUS */ - -#define __ARCH_RW_LOCK_UNLOCKED { RW_LOCK_BIAS } - -/* Actual code is in asm/spinlock.h or in arch/x86/lib/rwlock.S */ - -#endif /* _ASM_X86_RWLOCK_H */ diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h index 54f1c8068c0..9295016485c 100644 --- a/arch/x86/include/asm/spinlock.h +++ b/arch/x86/include/asm/spinlock.h @@ -187,7 +187,6 @@ static inline void arch_spin_unlock_wait(arch_spinlock_t *lock) cpu_relax(); } -#ifndef CONFIG_QUEUE_RWLOCK /* * Read-write spinlocks, allowing multiple readers * but only one writer. @@ -198,91 +197,15 @@ static inline void arch_spin_unlock_wait(arch_spinlock_t *lock) * irq-safe write-lock, but readers can get non-irqsafe * read-locks. * - * On x86, we implement read-write locks as a 32-bit counter - * with the high bit (sign) being the "contended" bit. + * On x86, we implement read-write locks using the generic qrwlock with + * x86 specific optimization. */ -/** - * read_can_lock - would read_trylock() succeed? - * @lock: the rwlock in question. - */ -static inline int arch_read_can_lock(arch_rwlock_t *lock) -{ - return lock->lock > 0; -} - -/** - * write_can_lock - would write_trylock() succeed? - * @lock: the rwlock in question. - */ -static inline int arch_write_can_lock(arch_rwlock_t *lock) -{ - return lock->write == WRITE_LOCK_CMP; -} - -static inline void arch_read_lock(arch_rwlock_t *rw) -{ - asm volatile(LOCK_PREFIX READ_LOCK_SIZE(dec) " (%0)\n\t" - "jns 1f\n" - "call __read_lock_failed\n\t" - "1:\n" - ::LOCK_PTR_REG (rw) : "memory"); -} - -static inline void arch_write_lock(arch_rwlock_t *rw) -{ - asm volatile(LOCK_PREFIX WRITE_LOCK_SUB(%1) "(%0)\n\t" - "jz 1f\n" - "call __write_lock_failed\n\t" - "1:\n" - ::LOCK_PTR_REG (&rw->write), "i" (RW_LOCK_BIAS) - : "memory"); -} - -static inline int arch_read_trylock(arch_rwlock_t *lock) -{ - READ_LOCK_ATOMIC(t) *count = (READ_LOCK_ATOMIC(t) *)lock; - - if (READ_LOCK_ATOMIC(dec_return)(count) >= 0) - return 1; - READ_LOCK_ATOMIC(inc)(count); - return 0; -} - -static inline int arch_write_trylock(arch_rwlock_t *lock) -{ - atomic_t *count = (atomic_t *)&lock->write; - - if (atomic_sub_and_test(WRITE_LOCK_CMP, count)) - return 1; - atomic_add(WRITE_LOCK_CMP, count); - return 0; -} - -static inline void arch_read_unlock(arch_rwlock_t *rw) -{ - asm volatile(LOCK_PREFIX READ_LOCK_SIZE(inc) " %0" - :"+m" (rw->lock) : : "memory"); -} - -static inline void arch_write_unlock(arch_rwlock_t *rw) -{ - asm volatile(LOCK_PREFIX WRITE_LOCK_ADD(%1) "%0" - : "+m" (rw->write) : "i" (RW_LOCK_BIAS) : "memory"); -} -#else #include <asm/qrwlock.h> -#endif /* CONFIG_QUEUE_RWLOCK */ #define arch_read_lock_flags(lock, flags) arch_read_lock(lock) #define arch_write_lock_flags(lock, flags) arch_write_lock(lock) -#undef READ_LOCK_SIZE -#undef READ_LOCK_ATOMIC -#undef WRITE_LOCK_ADD -#undef WRITE_LOCK_SUB -#undef WRITE_LOCK_CMP - #define arch_spin_relax(lock) cpu_relax() #define arch_read_relax(lock) cpu_relax() #define arch_write_relax(lock) cpu_relax() diff --git a/arch/x86/include/asm/spinlock_types.h b/arch/x86/include/asm/spinlock_types.h index 73c4c007200..5f9d7572d82 100644 --- a/arch/x86/include/asm/spinlock_types.h +++ b/arch/x86/include/asm/spinlock_types.h @@ -34,10 +34,6 @@ typedef struct arch_spinlock { #define __ARCH_SPIN_LOCK_UNLOCKED { { 0 } } -#ifdef CONFIG_QUEUE_RWLOCK #include <asm-generic/qrwlock_types.h> -#else -#include <asm/rwlock.h> -#endif #endif /* _ASM_X86_SPINLOCK_TYPES_H */ diff --git a/arch/x86/lib/Makefile b/arch/x86/lib/Makefile index 4d4f96a2763..7ef9a30e7da 100644 --- a/arch/x86/lib/Makefile +++ b/arch/x86/lib/Makefile @@ -20,7 +20,6 @@ lib-y := delay.o misc.o cmdline.o lib-y += thunk_$(BITS).o lib-y += usercopy_$(BITS).o usercopy.o getuser.o putuser.o lib-y += memcpy_$(BITS).o -lib-$(CONFIG_SMP) += rwlock.o lib-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem.o lib-$(CONFIG_INSTRUCTION_DECODER) += insn.o inat.o diff --git a/arch/x86/lib/rwlock.S b/arch/x86/lib/rwlock.S deleted file mode 100644 index 1cad22139c8..00000000000 --- a/arch/x86/lib/rwlock.S +++ /dev/null @@ -1,44 +0,0 @@ -/* Slow paths of read/write spinlocks. */ - -#include <linux/linkage.h> -#include <asm/alternative-asm.h> -#include <asm/frame.h> -#include <asm/rwlock.h> - -#ifdef CONFIG_X86_32 -# define __lock_ptr eax -#else -# define __lock_ptr rdi -#endif - -ENTRY(__write_lock_failed) - CFI_STARTPROC - FRAME -0: LOCK_PREFIX - WRITE_LOCK_ADD($RW_LOCK_BIAS) (%__lock_ptr) -1: rep; nop - cmpl $WRITE_LOCK_CMP, (%__lock_ptr) - jne 1b - LOCK_PREFIX - WRITE_LOCK_SUB($RW_LOCK_BIAS) (%__lock_ptr) - jnz 0b - ENDFRAME - ret - CFI_ENDPROC -END(__write_lock_failed) - -ENTRY(__read_lock_failed) - CFI_STARTPROC - FRAME -0: LOCK_PREFIX - READ_LOCK_SIZE(inc) (%__lock_ptr) -1: rep; nop - READ_LOCK_SIZE(cmp) $1, (%__lock_ptr) - js 1b - LOCK_PREFIX - READ_LOCK_SIZE(dec) (%__lock_ptr) - js 0b - ENDFRAME - ret - CFI_ENDPROC -END(__read_lock_failed) |