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authorJeremy Fitzhardinge <jeremy@goop.org>2013-08-09 19:51:55 +0530
committerH. Peter Anvin <hpa@linux.intel.com>2013-08-09 07:53:44 -0700
commit354714dd2607778692db53947ab93b74956494e5 (patch)
treef02add96b7d26f88cee9383ed522f7d67264e9bc /arch/x86/xen
parentb8fa70b51aa76737bdb6b493901ef7376977489c (diff)
x86, pvticketlock: Use callee-save for lock_spinning
Although the lock_spinning calls in the spinlock code are on the uncommon path, their presence can cause the compiler to generate many more register save/restores in the function pre/postamble, which is in the fast path. To avoid this, convert it to using the pvops callee-save calling convention, which defers all the save/restores until the actual function is called, keeping the fastpath clean. Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org> Link: http://lkml.kernel.org/r/1376058122-8248-8-git-send-email-raghavendra.kt@linux.vnet.ibm.com Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Tested-by: Attilio Rao <attilio.rao@citrix.com> Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Acked-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/xen')
-rw-r--r--arch/x86/xen/spinlock.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
index 669a971c78fd..6c8792b298ed 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -173,6 +173,7 @@ out:
local_irq_restore(flags);
spin_time_accum_blocked(start);
}
+PV_CALLEE_SAVE_REGS_THUNK(xen_lock_spinning);
static void xen_unlock_kick(struct arch_spinlock *lock, __ticket_t next)
{
@@ -260,7 +261,7 @@ void __init xen_init_spinlocks(void)
return;
}
- pv_lock_ops.lock_spinning = xen_lock_spinning;
+ pv_lock_ops.lock_spinning = PV_CALLEE_SAVE(xen_lock_spinning);
pv_lock_ops.unlock_kick = xen_unlock_kick;
}