locking/rwsem: Remove rwsem-spinlock.c & use rwsem-xadd.c for all archs

Currently, we have two different implementation of rwsem: 1) CONFIG_RWSEM_GENERIC_SPINLOCK (rwsem-spinlock.c) 2) CONFIG_RWSEM_XCHGADD_ALGORITHM (rwsem-xadd.c) As we are going to use a single generic implementation for rwsem-xadd.c and no architecture-specific code will be needed, there is no point in keeping two different implementations of rwsem. In most cases, the performance of rwsem-spinlock.c will be worse. It also doesn't get all the performance tuning and optimizations that had been implemented in rwsem-xadd.c over the years. For simplication, we are going to remove rwsem-spinlock.c and make all architectures use a single implementation of rwsem - rwsem-xadd.c. All references to RWSEM_GENERIC_SPINLOCK and RWSEM_XCHGADD_ALGORITHM in the code are removed. Suggested-by: Peter Zijlstra <[email protected]> Signed-off-by: Waiman Long <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Acked-by: Linus Torvalds <[email protected]> Cc: Andrew Morton <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Davidlohr Bueso <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Paul E. McKenney <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Tim Chen <[email protected]> Cc: Will Deacon <[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: https://lkml.kernel.org/r/[email protected] Signed-off-by: Ingo Molnar <[email protected]>
niw · Apr 3, 2019 · 390a0c6 · 390a0c6
1 parent 46ad084
commit 390a0c6
Show file tree

Hide file tree

Showing 31 changed files with 2 additions and 520 deletions.
diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
@@ -49,13 +49,6 @@ config MMU
 	bool
 	default y
 
-config RWSEM_GENERIC_SPINLOCK
-	bool
-
-config RWSEM_XCHGADD_ALGORITHM
-	bool
-	default y
-
 config ARCH_HAS_ILOG2_U32
 	bool
 	default n

diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
@@ -63,9 +63,6 @@ config SCHED_OMIT_FRAME_POINTER
 config GENERIC_CSUM
 	def_bool y
 
-config RWSEM_GENERIC_SPINLOCK
-	def_bool y
-
 config ARCH_DISCONTIGMEM_ENABLE
 	def_bool n
 

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
@@ -178,10 +178,6 @@ config TRACE_IRQFLAGS_SUPPORT
 	bool
 	default !CPU_V7M
 
-config RWSEM_XCHGADD_ALGORITHM
-	bool
-	default y
-
 config ARCH_HAS_ILOG2_U32
 	bool
 

diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
@@ -237,9 +237,6 @@ config LOCKDEP_SUPPORT
 config TRACE_IRQFLAGS_SUPPORT
 	def_bool y
 
-config RWSEM_XCHGADD_ALGORITHM
-	def_bool y
-
 config GENERIC_BUG
 	def_bool y
 	depends on BUG

diff --git a/arch/c6x/Kconfig b/arch/c6x/Kconfig
@@ -27,9 +27,6 @@ config MMU
 config FPU
 	def_bool n
 
-config RWSEM_GENERIC_SPINLOCK
-	def_bool y
-
 config GENERIC_CALIBRATE_DELAY
 	def_bool y
 

diff --git a/arch/csky/Kconfig b/arch/csky/Kconfig
@@ -92,9 +92,6 @@ config GENERIC_HWEIGHT
 config MMU
 	def_bool y
 
-config RWSEM_GENERIC_SPINLOCK
-	def_bool y
-
 config STACKTRACE_SUPPORT
 	def_bool y
 

diff --git a/arch/h8300/Kconfig b/arch/h8300/Kconfig
@@ -27,9 +27,6 @@ config H8300
 config CPU_BIG_ENDIAN
 	def_bool y
 
-config RWSEM_GENERIC_SPINLOCK
-	def_bool y
-
 config GENERIC_HWEIGHT
 	def_bool y
 

diff --git a/arch/hexagon/Kconfig b/arch/hexagon/Kconfig
@@ -65,12 +65,6 @@ config GENERIC_CSUM
 config GENERIC_IRQ_PROBE
 	def_bool y
 
-config RWSEM_GENERIC_SPINLOCK
-	def_bool n
-
-config RWSEM_XCHGADD_ALGORITHM
-	def_bool y
-
 config GENERIC_HWEIGHT
 	def_bool y
 

diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
@@ -83,10 +83,6 @@ config STACKTRACE_SUPPORT
 config GENERIC_LOCKBREAK
 	def_bool n
 
-config RWSEM_XCHGADD_ALGORITHM
-	bool
-	default y
-
 config HUGETLB_PAGE_SIZE_VARIABLE
 	bool
 	depends on HUGETLB_PAGE

diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
@@ -32,13 +32,6 @@ config M68K
 config CPU_BIG_ENDIAN
 	def_bool y
 
-config RWSEM_GENERIC_SPINLOCK
-	bool
-	default y
-
-config RWSEM_XCHGADD_ALGORITHM
-	bool
-
 config ARCH_HAS_ILOG2_U32
 	bool
 

diff --git a/arch/microblaze/Kconfig b/arch/microblaze/Kconfig
@@ -58,15 +58,9 @@ config CPU_LITTLE_ENDIAN
 
 endchoice
 
-config RWSEM_GENERIC_SPINLOCK
-	def_bool y
-
 config ZONE_DMA
 	def_bool y
 
-config RWSEM_XCHGADD_ALGORITHM
-	bool
-
 config ARCH_HAS_ILOG2_U32
 	def_bool n
 

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
@@ -1037,13 +1037,6 @@ source "arch/mips/paravirt/Kconfig"
 
 endmenu
 
-config RWSEM_GENERIC_SPINLOCK
-	bool
-	default y
-
-config RWSEM_XCHGADD_ALGORITHM
-	bool
-
 config GENERIC_HWEIGHT
 	bool
 	default y

diff --git a/arch/nds32/Kconfig b/arch/nds32/Kconfig
@@ -60,9 +60,6 @@ config GENERIC_LOCKBREAK
         def_bool y
 	depends on PREEMPT
 
-config RWSEM_GENERIC_SPINLOCK
-	def_bool y
-
 config TRACE_IRQFLAGS_SUPPORT
 	def_bool y
 

diff --git a/arch/nios2/Kconfig b/arch/nios2/Kconfig
@@ -40,9 +40,6 @@ config NO_IOPORT_MAP
 config FPU
 	def_bool n
 
-config RWSEM_GENERIC_SPINLOCK
-	def_bool y
-
 config TRACE_IRQFLAGS_SUPPORT
 	def_bool n
 

diff --git a/arch/openrisc/Kconfig b/arch/openrisc/Kconfig
@@ -43,12 +43,6 @@ config CPU_BIG_ENDIAN
 config MMU
 	def_bool y
 
-config RWSEM_GENERIC_SPINLOCK
-	def_bool y
-
-config RWSEM_XCHGADD_ALGORITHM
-	def_bool n
-
 config GENERIC_HWEIGHT
 	def_bool y
 

diff --git a/arch/parisc/Kconfig b/arch/parisc/Kconfig
@@ -75,12 +75,6 @@ config GENERIC_LOCKBREAK
 	default y
 	depends on SMP && PREEMPT
 
-config RWSEM_GENERIC_SPINLOCK
-	def_bool y
-
-config RWSEM_XCHGADD_ALGORITHM
-	bool
-
 config ARCH_HAS_ILOG2_U32
 	bool
 	default n

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
@@ -103,13 +103,6 @@ config LOCKDEP_SUPPORT
 	bool
 	default y
 
-config RWSEM_GENERIC_SPINLOCK
-	bool
-
-config RWSEM_XCHGADD_ALGORITHM
-	bool
-	default y
-
 config GENERIC_LOCKBREAK
 	bool
 	default y

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
@@ -69,9 +69,6 @@ config STACKTRACE_SUPPORT
 config TRACE_IRQFLAGS_SUPPORT
 	def_bool y
 
-config RWSEM_GENERIC_SPINLOCK
-	def_bool y
-
 config GENERIC_BUG
 	def_bool y
 	depends on BUG

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
@@ -14,12 +14,6 @@ config LOCKDEP_SUPPORT
 config STACKTRACE_SUPPORT
 	def_bool y
 
-config RWSEM_GENERIC_SPINLOCK
-	bool
-
-config RWSEM_XCHGADD_ALGORITHM
-	def_bool y
-
 config ARCH_HAS_ILOG2_U32
 	def_bool n
 

diff --git a/arch/sh/Kconfig b/arch/sh/Kconfig
@@ -90,12 +90,6 @@ config ARCH_DEFCONFIG
 	default "arch/sh/configs/shx3_defconfig" if SUPERH32
 	default "arch/sh/configs/cayman_defconfig" if SUPERH64
 
-config RWSEM_GENERIC_SPINLOCK
-	def_bool y
-
-config RWSEM_XCHGADD_ALGORITHM
-	bool
-
 config GENERIC_BUG
 	def_bool y
 	depends on BUG && SUPERH32

diff --git a/arch/sparc/Kconfig b/arch/sparc/Kconfig
@@ -191,14 +191,6 @@ config NR_CPUS
 
 source "kernel/Kconfig.hz"
 
-config RWSEM_GENERIC_SPINLOCK
-	bool
-	default y if SPARC32
-
-config RWSEM_XCHGADD_ALGORITHM
-	bool
-	default y if SPARC64
-
 config GENERIC_HWEIGHT
 	bool
 	default y

diff --git a/arch/unicore32/Kconfig b/arch/unicore32/Kconfig
@@ -38,12 +38,6 @@ config STACKTRACE_SUPPORT
 config LOCKDEP_SUPPORT
 	def_bool y
 
-config RWSEM_GENERIC_SPINLOCK
-	def_bool y
-
-config RWSEM_XCHGADD_ALGORITHM
-	bool
-
 config ARCH_HAS_ILOG2_U32
 	bool
 

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
@@ -268,9 +268,6 @@ config ARCH_MAY_HAVE_PC_FDC
 	def_bool y
 	depends on ISA_DMA_API
 
-config RWSEM_XCHGADD_ALGORITHM
-	def_bool y
-
 config GENERIC_CALIBRATE_DELAY
 	def_bool y
 

diff --git a/arch/x86/um/Kconfig b/arch/x86/um/Kconfig
@@ -32,12 +32,6 @@ config ARCH_DEFCONFIG
 	default "arch/um/configs/i386_defconfig" if X86_32
 	default "arch/um/configs/x86_64_defconfig" if X86_64
 
-config RWSEM_XCHGADD_ALGORITHM
-	def_bool 64BIT
-
-config RWSEM_GENERIC_SPINLOCK
-	def_bool !RWSEM_XCHGADD_ALGORITHM
-
 config 3_LEVEL_PGTABLES
 	bool "Three-level pagetables" if !64BIT
 	default 64BIT

diff --git a/arch/xtensa/Kconfig b/arch/xtensa/Kconfig
@@ -46,9 +46,6 @@ config XTENSA
 	  with reasonable minimum requirements.  The Xtensa Linux project has
 	  a home page at <http://www.linux-xtensa.org/>.
 
-config RWSEM_XCHGADD_ALGORITHM
-	def_bool y
-
 config GENERIC_HWEIGHT
 	def_bool y
 

diff --git a/include/linux/rwsem-spinlock.h b/include/linux/rwsem-spinlock.h
diff --git a/include/linux/rwsem.h b/include/linux/rwsem.h
@@ -22,10 +22,6 @@
 
 struct rw_semaphore;
 
-#ifdef CONFIG_RWSEM_GENERIC_SPINLOCK
-#include <linux/rwsem-spinlock.h> /* use a generic implementation */
-#define __RWSEM_INIT_COUNT(name)	.count = RWSEM_UNLOCKED_VALUE
-#else
 /* All arch specific implementations share the same struct */
 struct rw_semaphore {
 	atomic_long_t count;
@@ -65,7 +61,6 @@ static inline int rwsem_is_locked(struct rw_semaphore *sem)
 
 #define RWSEM_UNLOCKED_VALUE		0L
 #define __RWSEM_INIT_COUNT(name)	.count = ATOMIC_LONG_INIT(RWSEM_UNLOCKED_VALUE)
-#endif
 
 /* Common initializer macros and functions */
 

diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks
@@ -229,7 +229,7 @@ config MUTEX_SPIN_ON_OWNER
 
 config RWSEM_SPIN_ON_OWNER
        def_bool y
-       depends on SMP && RWSEM_XCHGADD_ALGORITHM && ARCH_SUPPORTS_ATOMIC_RMW
+       depends on SMP && ARCH_SUPPORTS_ATOMIC_RMW
 
 config LOCK_SPIN_ON_OWNER
        def_bool y

diff --git a/kernel/locking/Makefile b/kernel/locking/Makefile
@@ -3,7 +3,7 @@
 # and is generally not a function of system call inputs.
 KCOV_INSTRUMENT		:= n
 
-obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o
+obj-y += mutex.o semaphore.o rwsem.o percpu-rwsem.o rwsem-xadd.o
 
 ifdef CONFIG_FUNCTION_TRACER
 CFLAGS_REMOVE_lockdep.o = $(CC_FLAGS_FTRACE)
@@ -25,8 +25,6 @@ obj-$(CONFIG_RT_MUTEXES) += rtmutex.o
 obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
 obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
-obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
-obj-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem-xadd.o
 obj-$(CONFIG_QUEUED_RWLOCKS) += qrwlock.o
 obj-$(CONFIG_LOCK_TORTURE_TEST) += locktorture.o
 obj-$(CONFIG_WW_MUTEX_SELFTEST) += test-ww_mutex.o