linux-kernel - [PATCH v2] x86, locking/spinlocks: Remove paravirt_ticketlocks

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Message-Id: <1484252878-1962-1-git-send-email-longman@redhat.com>
Date:   Thu, 12 Jan 2017 15:27:58 -0500
From:   Waiman Long <longman@...hat.com>
To:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        "H. Peter Anvin" <hpa@...or.com>
Cc:     linux-arch@...r.kernel.org, x86@...nel.org,
        linux-kernel@...r.kernel.org,
        virtualization@...ts.linux-foundation.org,
        xen-devel@...ts.xenproject.org, kvm@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Jeremy Fitzhardinge <jeremy@...p.org>,
        Chris Wright <chrisw@...s-sol.org>,
        Alok Kataria <akataria@...are.com>,
        Rusty Russell <rusty@...tcorp.com.au>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        Juergen Gross <jgross@...e.com>,
        Waiman Long <longman@...hat.com>
Subject: [PATCH v2] x86, locking/spinlocks: Remove paravirt_ticketlocks_enabled

This is a follow-up of commit cfd8983f03c7b2 ("x86, locking/spinlocks:
Remove ticket (spin)lock implementation"). The static_key structure
paravirt_ticketlocks_enabled is now removed as it is no longer used.
As a result, the init functions kvm_spinlock_init_jump() and
xen_init_spinlocks_jump() are also removed.

A simple build and boot test was done to verify it.

Signed-off-by: Waiman Long <longman@...hat.com>
---
 v1->v2:
  - Remove init functions kvm_spinlock_init_jump() and
    xen_init_spinlocks_jump().

 arch/x86/include/asm/spinlock.h      |  3 ---
 arch/x86/kernel/kvm.c                | 14 --------------
 arch/x86/kernel/paravirt-spinlocks.c |  3 ---
 arch/x86/xen/spinlock.c              | 19 -------------------
 4 files changed, 39 deletions(-)

diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h
index 921bea7..6d39190 100644
--- a/arch/x86/include/asm/spinlock.h
+++ b/arch/x86/include/asm/spinlock.h
@@ -23,9 +23,6 @@
 /* How long a lock should spin before we consider blocking */
 #define SPIN_THRESHOLD	(1 << 15)
 
-extern struct static_key paravirt_ticketlocks_enabled;
-static __always_inline bool static_key_false(struct static_key *key);
-
 #include <asm/qspinlock.h>
 
 /*
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 36bc664..099fcba 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -620,18 +620,4 @@ void __init kvm_spinlock_init(void)
 	}
 }
 
-static __init int kvm_spinlock_init_jump(void)
-{
-	if (!kvm_para_available())
-		return 0;
-	if (!kvm_para_has_feature(KVM_FEATURE_PV_UNHALT))
-		return 0;
-
-	static_key_slow_inc(&paravirt_ticketlocks_enabled);
-	printk(KERN_INFO "KVM setup paravirtual spinlock\n");
-
-	return 0;
-}
-early_initcall(kvm_spinlock_init_jump);
-
 #endif	/* CONFIG_PARAVIRT_SPINLOCKS */
diff --git a/arch/x86/kernel/paravirt-spinlocks.c b/arch/x86/kernel/paravirt-spinlocks.c
index 6d4bf81..6259327 100644
--- a/arch/x86/kernel/paravirt-spinlocks.c
+++ b/arch/x86/kernel/paravirt-spinlocks.c
@@ -42,6 +42,3 @@ struct pv_lock_ops pv_lock_ops = {
 #endif /* SMP */
 };
 EXPORT_SYMBOL(pv_lock_ops);
-
-struct static_key paravirt_ticketlocks_enabled = STATIC_KEY_INIT_FALSE;
-EXPORT_SYMBOL(paravirt_ticketlocks_enabled);
diff --git a/arch/x86/xen/spinlock.c b/arch/x86/xen/spinlock.c
index e8a9ea7..25a7c43 100644
--- a/arch/x86/xen/spinlock.c
+++ b/arch/x86/xen/spinlock.c
@@ -141,25 +141,6 @@ void __init xen_init_spinlocks(void)
 	pv_lock_ops.vcpu_is_preempted = PV_CALLEE_SAVE(xen_vcpu_stolen);
 }
 
-/*
- * While the jump_label init code needs to happend _after_ the jump labels are
- * enabled and before SMP is started. Hence we use pre-SMP initcall level
- * init. We cannot do it in xen_init_spinlocks as that is done before
- * jump labels are activated.
- */
-static __init int xen_init_spinlocks_jump(void)
-{
-	if (!xen_pvspin)
-		return 0;
-
-	if (!xen_domain())
-		return 0;
-
-	static_key_slow_inc(&paravirt_ticketlocks_enabled);
-	return 0;
-}
-early_initcall(xen_init_spinlocks_jump);
-
 static __init int xen_parse_nopvspin(char *arg)
 {
 	xen_pvspin = false;
-- 
1.8.3.1