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authorHisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp>2008-01-26 14:11:28 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2008-01-26 14:11:31 +0100
commit894cdde26b538c77b9943bc72f0570abf6e58e37 (patch)
tree335f75460bd947c4969c9b7a1ec5764b98bf1d2b
parent[S390] add smp_call_function_mask (diff)
downloadlinux-894cdde26b538c77b9943bc72f0570abf6e58e37.tar.xz
linux-894cdde26b538c77b9943bc72f0570abf6e58e37.zip
[S390] do local_irq_restore while spinning in spin_lock_irqsave.
In s390's spin_lock_irqsave, interrupts remain disabled while spinning. In other architectures like x86 and powerpc, interrupts are re-enabled while spinning if IRQ is not masked before spin_lock_irqsave is called. The following patch re-enables interrupts through local_irq_restore while spinning for a lock acquisition. This can improve system response. [heiko.carstens@de.ibm.com: removed saving of pc] Signed-off-by: Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
-rw-r--r--arch/s390/lib/spinlock.c23
-rw-r--r--include/asm-s390/spinlock.h13
2 files changed, 35 insertions, 1 deletions
diff --git a/arch/s390/lib/spinlock.c b/arch/s390/lib/spinlock.c
index 59c56c3d72d0..e41f4008afc5 100644
--- a/arch/s390/lib/spinlock.c
+++ b/arch/s390/lib/spinlock.c
@@ -59,6 +59,29 @@ void _raw_spin_lock_wait(raw_spinlock_t *lp)
}
EXPORT_SYMBOL(_raw_spin_lock_wait);
+void _raw_spin_lock_wait_flags(raw_spinlock_t *lp, unsigned long flags)
+{
+ int count = spin_retry;
+ unsigned int cpu = ~smp_processor_id();
+
+ local_irq_restore(flags);
+ while (1) {
+ if (count-- <= 0) {
+ unsigned int owner = lp->owner_cpu;
+ if (owner != 0)
+ _raw_yield_cpu(~owner);
+ count = spin_retry;
+ }
+ if (__raw_spin_is_locked(lp))
+ continue;
+ local_irq_disable();
+ if (_raw_compare_and_swap(&lp->owner_cpu, 0, cpu) == 0)
+ return;
+ local_irq_restore(flags);
+ }
+}
+EXPORT_SYMBOL(_raw_spin_lock_wait_flags);
+
int _raw_spin_trylock_retry(raw_spinlock_t *lp)
{
unsigned int cpu = ~smp_processor_id();
diff --git a/include/asm-s390/spinlock.h b/include/asm-s390/spinlock.h
index c1d6e7e304e2..df84ae96915f 100644
--- a/include/asm-s390/spinlock.h
+++ b/include/asm-s390/spinlock.h
@@ -53,12 +53,12 @@ _raw_compare_and_swap(volatile unsigned int *lock,
*/
#define __raw_spin_is_locked(x) ((x)->owner_cpu != 0)
-#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
#define __raw_spin_unlock_wait(lock) \
do { while (__raw_spin_is_locked(lock)) \
_raw_spin_relax(lock); } while (0)
extern void _raw_spin_lock_wait(raw_spinlock_t *);
+extern void _raw_spin_lock_wait_flags(raw_spinlock_t *, unsigned long flags);
extern int _raw_spin_trylock_retry(raw_spinlock_t *);
extern void _raw_spin_relax(raw_spinlock_t *lock);
@@ -72,6 +72,17 @@ static inline void __raw_spin_lock(raw_spinlock_t *lp)
_raw_spin_lock_wait(lp);
}
+static inline void __raw_spin_lock_flags(raw_spinlock_t *lp,
+ unsigned long flags)
+{
+ int old;
+
+ old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id());
+ if (likely(old == 0))
+ return;
+ _raw_spin_lock_wait_flags(lp, flags);
+}
+
static inline int __raw_spin_trylock(raw_spinlock_t *lp)
{
int old;