spinlock: lockbreak cleanup (95c354fe) · Commits · 戴 / test

The break_lock data structure and code for spinlocks is quite nasty. Not only does it double the size of a spinlock but it changes locking to a potentially less optimal trylock. Put all of that under CONFIG_GENERIC_LOCKBREAK, and introduce a __raw_spin_is_contended that uses the lock data itself to determine whether there are waiters on the lock, to be used if CONFIG_GENERIC_LOCKBREAK is not set. Rename need_lockbreak to spin_needbreak, make it use spin_is_contended to decouple it from the spinlock implementation, and make it typesafe (rwlocks do not have any need_lockbreak sites -- why do they even get bloated up with that break_lock then?). Signed-off-by:

Nick Piggin <npiggin@suse.de> Signed-off-by:

Ingo Molnar <mingo@elte.hu> Signed-off-by:

Thomas Gleixner <tglx@linutronix.de>

arch/arm/Kconfig

+5 −0

Original line number	Diff line number	Diff line
		@@ -91,6 +91,11 @@ config GENERIC_IRQ_PROBE
		bool
		default y

		config GENERIC_LOCKBREAK
		bool
		default y
		depends on SMP && PREEMPT

		config RWSEM_GENERIC_SPINLOCK
		bool
		default y

arch/ia64/Kconfig

+5 −0

Original line number	Diff line number	Diff line
		@@ -42,6 +42,11 @@ config MMU
		config SWIOTLB
		bool

		config GENERIC_LOCKBREAK
		bool
		default y
		depends on SMP && PREEMPT

		config RWSEM_XCHGADD_ALGORITHM
		bool
		default y

arch/m32r/Kconfig

+5 −0

Original line number	Diff line number	Diff line
		@@ -235,6 +235,11 @@ config IRAM_SIZE
		# Define implied options from the CPU selection here
		#

		config GENERIC_LOCKBREAK
		bool
		default y
		depends on SMP && PREEMPT

		config RWSEM_GENERIC_SPINLOCK
		bool
		depends on M32R

arch/mips/Kconfig

+5 −0

Original line number	Diff line number	Diff line
		@@ -694,6 +694,11 @@ source "arch/mips/vr41xx/Kconfig"

		endmenu

		config GENERIC_LOCKBREAK
		bool
		default y
		depends on SMP && PREEMPT

		config RWSEM_GENERIC_SPINLOCK
		bool
		default y

arch/parisc/Kconfig

+5 −0

Original line number	Diff line number	Diff line
		@@ -19,6 +19,11 @@ config MMU
		config STACK_GROWSUP
		def_bool y

		config GENERIC_LOCKBREAK
		bool
		default y
		depends on SMP && PREEMPT

		config RWSEM_GENERIC_SPINLOCK
		def_bool y

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