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authorRobin Holt <holt@sgi.com>2009-04-03 03:59:45 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2009-04-03 06:05:10 +0400
commite8c158bb313c1df421eab7dc4299cd39cbbf5895 (patch)
tree8a5f1d01e58d0e358b2b0c9407fc494912e83c27 /include
parent41d577aa35aa0504fe28b76a948908bdb7fbec81 (diff)
downloadlinux-e8c158bb313c1df421eab7dc4299cd39cbbf5895.tar.xz
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>
Diffstat (limited to 'include')
-rw-r--r--include/linux/lockdep.h17
1 files changed, 17 insertions, 0 deletions
diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h
index 5a58ea3e91e9..da5a5a1f4cd2 100644
--- a/include/linux/lockdep.h
+++ b/include/linux/lockdep.h
@@ -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