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

[Jeremy Fitzhardinge <jeremy@xxxxxxxx>]

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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