[PATCH 09/13] x86/pvticketlocks: we only need to kick if there's waiters

From: Jeremy Fitzhardinge
Date: Thu Sep 01 2011 - 20:57:40 EST


From: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>

If we're releasing the lock into an uncontended state, there's nobody
waiting on it, so there's no need to kick anyone.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@xxxxxxxxxx>
---
arch/x86/kernel/paravirt-spinlocks.c | 3 +--
1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kernel/paravirt-spinlocks.c b/arch/x86/kernel/paravirt-spinlocks.c
index 21b6986..71b8557 100644
--- a/arch/x86/kernel/paravirt-spinlocks.c
+++ b/arch/x86/kernel/paravirt-spinlocks.c
@@ -47,8 +47,7 @@ void __ticket_unlock_release_slowpath(struct arch_spinlock *lock)
old.head_tail, new.head_tail) != old.head_tail) {
/* still people waiting */
__ticket_unlock_release(lock);
+ __ticket_unlock_kick(lock, new.tickets.head);
}
-
- __ticket_unlock_kick(lock, new.tickets.head);
}
EXPORT_SYMBOL(__ticket_unlock_release_slowpath);
--
1.7.6

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