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https://github.com/edk2-porting/linux-next.git
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70af2f8a4f
This rwlock uses the arch_spin_lock_t as a waitqueue, and assuming the arch_spin_lock_t is a fair lock (ticket,mcs etc..) the resulting rwlock is a fair lock. It fits in the same 8 bytes as the regular rwlock_t by folding the reader and writer count into a single integer, using the remaining 4 bytes for the arch_spinlock_t. Architectures that can single-copy adress bytes can optimize queue_write_unlock() with a 0 write to the LSB (the write count). Performance as measured by Davidlohr Bueso (rwlock_t -> qrwlock_t): +--------------+-------------+---------------+ | Workload | #users | delta | +--------------+-------------+---------------+ | alltests | > 1400 | -4.83% | | custom | 0-100,> 100 | +1.43%,-1.57% | | high_systime | > 1000 | -2.61 | | shared | all | +0.32 | +--------------+-------------+---------------+ http://www.stgolabs.net/qrwlock-stuff/aim7-results-vs-rwsem_optsin/ Signed-off-by: Waiman Long <Waiman.Long@hp.com> [peterz: near complete rewrite] Signed-off-by: Peter Zijlstra <peterz@infradead.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: "Paul E.McKenney" <paulmck@linux.vnet.ibm.com> Cc: linux-arch@vger.kernel.org Cc: linux-kernel@vger.kernel.org Link: http://lkml.kernel.org/n/tip-gac1nnl3wvs2ij87zv2xkdzq@git.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
29 lines
957 B
Makefile
29 lines
957 B
Makefile
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obj-y += mutex.o semaphore.o rwsem.o mcs_spinlock.o
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ifdef CONFIG_FUNCTION_TRACER
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CFLAGS_REMOVE_lockdep.o = -pg
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CFLAGS_REMOVE_lockdep_proc.o = -pg
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CFLAGS_REMOVE_mutex-debug.o = -pg
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CFLAGS_REMOVE_rtmutex-debug.o = -pg
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endif
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obj-$(CONFIG_DEBUG_MUTEXES) += mutex-debug.o
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obj-$(CONFIG_LOCKDEP) += lockdep.o
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ifeq ($(CONFIG_PROC_FS),y)
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obj-$(CONFIG_LOCKDEP) += lockdep_proc.o
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endif
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obj-$(CONFIG_SMP) += spinlock.o
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obj-$(CONFIG_SMP) += lglock.o
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obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
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obj-$(CONFIG_RT_MUTEXES) += rtmutex.o
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obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
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obj-$(CONFIG_RT_MUTEX_TESTER) += rtmutex-tester.o
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obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
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obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock_debug.o
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obj-$(CONFIG_RWSEM_GENERIC_SPINLOCK) += rwsem-spinlock.o
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obj-$(CONFIG_RWSEM_XCHGADD_ALGORITHM) += rwsem-xadd.o
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obj-$(CONFIG_PERCPU_RWSEM) += percpu-rwsem.o
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obj-$(CONFIG_QUEUE_RWLOCK) += qrwlock.o
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obj-$(CONFIG_LOCK_TORTURE_TEST) += locktorture.o
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