Factor out #ifdefs from kernel/spinlock.c to LOCK_CONTENDED_FLAGS (e8c158bb) · Commits · 戴 / test

SGI has observed that on large systems, interrupts are not serviced for a long period of time when waiting for a rwlock. The following patch series re-enables irqs while waiting for the lock, resembling the code which is already there for spinlocks. I only made the ia64 version, because the patch adds some overhead to the fast path. I assume there is currently no demand to have this for other architectures, because the systems are not so large. Of course, the possibility to implement raw_{read|write}_lock_flags for any architecture is still there. This patch: The new macro LOCK_CONTENDED_FLAGS expands to the correct implementation depending on the config options, so that IRQ's are re-enabled when possible, but they remain disabled if CONFIG_LOCKDEP is set. Signed-off-by:

Petr Tesarik <ptesarik@suse.cz> Signed-off-by:

Robin Holt <holt@sgi.com> Cc: <linux-arch@vger.kernel.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by:

Andrew Morton <akpm@linux-foundation.org> Signed-off-by:

Linus Torvalds <torvalds@linux-foundation.org>

include/linux/lockdep.h

+17 −0

Original line number	Diff line number	Diff line
		@@ -364,6 +364,23 @@ do { \

		#endif /* CONFIG_LOCK_STAT */

		#ifdef CONFIG_LOCKDEP

		/*
		* On lockdep we dont want the hand-coded irq-enable of
		* _raw_*_lock_flags() code, because lockdep assumes
		* that interrupts are not re-enabled during lock-acquire:
		*/
		#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
		LOCK_CONTENDED((_lock), (try), (lock))

		#else /* CONFIG_LOCKDEP */

		#define LOCK_CONTENDED_FLAGS(_lock, try, lock, lockfl, flags) \
		lockfl((_lock), (flags))

		#endif /* CONFIG_LOCKDEP */

		#ifdef CONFIG_GENERIC_HARDIRQS
		extern void early_init_irq_lock_class(void);
		#else

kernel/spinlock.c

+2 −10

Original line number	Diff line number	Diff line
		@@ -299,16 +299,8 @@ unsigned long __lockfunc _spin_lock_irqsave_nested(spinlock_t *lock, int subclas
		local_irq_save(flags);
		preempt_disable();
		spin_acquire(&lock->dep_map, subclass, 0, _RET_IP_);
		/*
		* On lockdep we dont want the hand-coded irq-enable of
		* _raw_spin_lock_flags() code, because lockdep assumes
		* that interrupts are not re-enabled during lock-acquire:
		*/
		#ifdef CONFIG_LOCKDEP
		LOCK_CONTENDED(lock, _raw_spin_trylock, _raw_spin_lock);
		#else
		_raw_spin_lock_flags(lock, &flags);
		#endif
		LOCK_CONTENDED_FLAGS(lock, _raw_spin_trylock, _raw_spin_lock,
		_raw_spin_lock_flags, &flags);
		return flags;
		}
		EXPORT_SYMBOL(_spin_lock_irqsave_nested);

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