Factor out #ifdefs from kernel/spinlock.c to LOCK_CONTENDED_FLAGS
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>
diff --git a/kernel/spinlock.c b/kernel/spinlock.c
index 29ab207..7283c6d 100644
--- a/kernel/spinlock.c
+++ b/kernel/spinlock.c
@@ -299,16 +299,8 @@
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);