diff mbox

[resend] powerpc: enable qspinlock and its virtualization support

Message ID 5721EC0E.8040506@linux.vnet.ibm.com (mailing list archive)
State Superseded, archived
Headers show

Commit Message

xinhui April 28, 2016, 10:55 a.m. UTC
From: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>

This patch aims to enable qspinlock on PPC. And on pseries platform, it also support
paravirt qspinlock.

Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
---
 arch/powerpc/include/asm/qspinlock.h               | 37 +++++++++++++++
 arch/powerpc/include/asm/qspinlock_paravirt.h      | 36 +++++++++++++++
 .../powerpc/include/asm/qspinlock_paravirt_types.h | 13 ++++++
 arch/powerpc/include/asm/spinlock.h                | 31 ++++++++-----
 arch/powerpc/include/asm/spinlock_types.h          |  4 ++
 arch/powerpc/kernel/paravirt.c                     | 52 ++++++++++++++++++++++
 arch/powerpc/lib/locks.c                           | 32 +++++++++++++
 arch/powerpc/platforms/pseries/setup.c             |  5 +++
 8 files changed, 198 insertions(+), 12 deletions(-)
 create mode 100644 arch/powerpc/include/asm/qspinlock.h
 create mode 100644 arch/powerpc/include/asm/qspinlock_paravirt.h
 create mode 100644 arch/powerpc/include/asm/qspinlock_paravirt_types.h
 create mode 100644 arch/powerpc/kernel/paravirt.c

-- 2.4.3

Comments

Waiman Long April 28, 2016, 9:07 p.m. UTC | #1
On 04/28/2016 06:55 AM, Pan Xinhui wrote:
> From: Pan Xinhui<xinhui.pan@linux.vnet.ibm.com>
>
> This patch aims to enable qspinlock on PPC. And on pseries platform, it also support
> paravirt qspinlock.
>
> Signed-off-by: Pan Xinhui<xinhui.pan@linux.vnet.ibm.com>
> ---
>   arch/powerpc/include/asm/qspinlock.h               | 37 +++++++++++++++
>   arch/powerpc/include/asm/qspinlock_paravirt.h      | 36 +++++++++++++++
>   .../powerpc/include/asm/qspinlock_paravirt_types.h | 13 ++++++
>   arch/powerpc/include/asm/spinlock.h                | 31 ++++++++-----
>   arch/powerpc/include/asm/spinlock_types.h          |  4 ++
>   arch/powerpc/kernel/paravirt.c                     | 52 ++++++++++++++++++++++
>   arch/powerpc/lib/locks.c                           | 32 +++++++++++++
>   arch/powerpc/platforms/pseries/setup.c             |  5 +++
>   8 files changed, 198 insertions(+), 12 deletions(-)
>   create mode 100644 arch/powerpc/include/asm/qspinlock.h
>   create mode 100644 arch/powerpc/include/asm/qspinlock_paravirt.h
>   create mode 100644 arch/powerpc/include/asm/qspinlock_paravirt_types.h
>   create mode 100644 arch/powerpc/kernel/paravirt.c
>
>

This is just an enablement patch. You will also need a patch to activate 
qspinlock for, at lease, some PPC configs. Right?

It has dependency on the pv_wait() patch that I sent out extend the 
parameter list. Some performance data on how PPC system will perform 
with and without qspinlock will also be helpful data points.

Cheers,
Longman
diff mbox

Patch

diff --git a/arch/powerpc/include/asm/qspinlock.h b/arch/powerpc/include/asm/qspinlock.h
new file mode 100644
index 0000000..d4e4dc3
--- /dev/null
+++ b/arch/powerpc/include/asm/qspinlock.h
@@ -0,0 +1,37 @@ 
+#ifndef _ASM_POWERPC_QSPINLOCK_H
+#define _ASM_POWERPC_QSPINLOCK_H
+
+#include <asm-generic/qspinlock_types.h>
+
+#define SPIN_THRESHOLD	(1 << 15)
+#define	queued_spin_unlock queued_spin_unlock
+
+static inline void native_queued_spin_unlock(struct qspinlock *lock)
+{
+	/* no load/store can be across the unlock()*/
+	smp_store_release((u8 *)lock, 0);
+}
+
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+
+#include <asm/qspinlock_paravirt.h>
+
+static inline void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val)
+{
+	pv_queued_spin_lock(lock, val);
+}
+
+static inline void queued_spin_unlock(struct qspinlock *lock)
+{
+	pv_queued_spin_unlock(lock);
+}
+#else
+static inline void queued_spin_unlock(struct qspinlock *lock)
+{
+	native_queued_spin_unlock(lock);
+}
+#endif
+
+#include <asm-generic/qspinlock.h>
+
+#endif /* _ASM_POWERPC_QSPINLOCK_H */
diff --git a/arch/powerpc/include/asm/qspinlock_paravirt.h b/arch/powerpc/include/asm/qspinlock_paravirt.h
new file mode 100644
index 0000000..86e81c3
--- /dev/null
+++ b/arch/powerpc/include/asm/qspinlock_paravirt.h
@@ -0,0 +1,36 @@ 
+#ifndef CONFIG_PARAVIRT_SPINLOCKS
+#error "do not include this file"
+#endif
+
+#ifndef _ASM_QSPINLOCK_PARAVIRT_H
+#define _ASM_QSPINLOCK_PARAVIRT_H
+
+#include  <asm/qspinlock_paravirt_types.h>
+
+extern void pv_lock_init(void);
+extern void native_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
+extern void __pv_init_lock_hash(void);
+extern void __pv_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
+extern void __pv_queued_spin_unlock(struct qspinlock *lock);
+
+static inline void pv_queued_spin_lock(struct qspinlock *lock, u32 val)
+{
+	pv_lock_op.lock(lock, val);
+}
+
+static inline void pv_queued_spin_unlock(struct qspinlock *lock)
+{
+	pv_lock_op.unlock(lock);
+}
+
+static inline void pv_wait(u8 *ptr, u8 val)
+{
+	pv_lock_op.wait(ptr, val, -1);
+}
+
+static inline void pv_kick(int cpu)
+{
+	pv_lock_op.kick(cpu);
+}
+
+#endif
diff --git a/arch/powerpc/include/asm/qspinlock_paravirt_types.h b/arch/powerpc/include/asm/qspinlock_paravirt_types.h
new file mode 100644
index 0000000..e1fdeb0
--- /dev/null
+++ b/arch/powerpc/include/asm/qspinlock_paravirt_types.h
@@ -0,0 +1,13 @@ 
+#ifndef _ASM_QSPINLOCK_PARAVIRT_TYPES_H
+#define _ASM_QSPINLOCK_PARAVIRT_TYPES_H
+
+struct pv_lock_ops {
+	void (*lock)(struct qspinlock *lock, u32 val);
+	void (*unlock)(struct qspinlock *lock);
+	void (*wait)(u8 *ptr, u8 val, int cpu);
+	void (*kick)(int cpu);
+};
+
+extern struct pv_lock_ops pv_lock_op;
+
+#endif
diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h
index 523673d..3b65372 100644
--- a/arch/powerpc/include/asm/spinlock.h
+++ b/arch/powerpc/include/asm/spinlock.h
@@ -52,6 +52,24 @@ 
 #define SYNC_IO
 #endif
 
+#if defined(CONFIG_PPC_SPLPAR)
+/* We only yield to the hypervisor if we are in shared processor mode */
+#define SHARED_PROCESSOR (lppaca_shared_proc(local_paca->lppaca_ptr))
+extern void __spin_yield(arch_spinlock_t *lock);
+extern void __spin_yield_cpu(int cpu);
+extern void __spin_wake_cpu(int cpu);
+extern void __rw_yield(arch_rwlock_t *lock);
+#else /* SPLPAR */
+#define __spin_yield(x)	barrier()
+#define __spin_yield_cpu(x) barrier()
+#define __spin_wake_cpu(x) barrier()
+#define __rw_yield(x)	barrier()
+#define SHARED_PROCESSOR	0
+#endif
+
+#ifdef CONFIG_QUEUED_SPINLOCKS
+#include <asm/qspinlock.h>
+#else
 static __always_inline int arch_spin_value_unlocked(arch_spinlock_t lock)
 {
 	return lock.slock == 0;
@@ -106,18 +124,6 @@  static inline int arch_spin_trylock(arch_spinlock_t *lock)
  * held.  Conveniently, we have a word in the paca that holds this
  * value.
  */
-
-#if defined(CONFIG_PPC_SPLPAR)
-/* We only yield to the hypervisor if we are in shared processor mode */
-#define SHARED_PROCESSOR (lppaca_shared_proc(local_paca->lppaca_ptr))
-extern void __spin_yield(arch_spinlock_t *lock);
-extern void __rw_yield(arch_rwlock_t *lock);
-#else /* SPLPAR */
-#define __spin_yield(x)	barrier()
-#define __rw_yield(x)	barrier()
-#define SHARED_PROCESSOR	0
-#endif
-
 static inline void arch_spin_lock(arch_spinlock_t *lock)
 {
 	CLEAR_IO_SYNC;
@@ -169,6 +175,7 @@  extern void arch_spin_unlock_wait(arch_spinlock_t *lock);
 	do { while (arch_spin_is_locked(lock)) cpu_relax(); } while (0)
 #endif
 
+#endif /* !CONFIG_QUEUED_SPINLOCKS */
 /*
  * Read-write spinlocks, allowing multiple readers
  * but only one writer.
diff --git a/arch/powerpc/include/asm/spinlock_types.h b/arch/powerpc/include/asm/spinlock_types.h
index 2351adc..bd7144e 100644
--- a/arch/powerpc/include/asm/spinlock_types.h
+++ b/arch/powerpc/include/asm/spinlock_types.h
@@ -5,11 +5,15 @@ 
 # error "please don't include this file directly"
 #endif
 
+#ifdef CONFIG_QUEUED_SPINLOCKS
+#include <asm-generic/qspinlock_types.h>
+#else
 typedef struct {
 	volatile unsigned int slock;
 } arch_spinlock_t;
 
 #define __ARCH_SPIN_LOCK_UNLOCKED	{ 0 }
+#endif
 
 typedef struct {
 	volatile signed int lock;
diff --git a/arch/powerpc/kernel/paravirt.c b/arch/powerpc/kernel/paravirt.c
new file mode 100644
index 0000000..355c9fb
--- /dev/null
+++ b/arch/powerpc/kernel/paravirt.c
@@ -0,0 +1,52 @@ 
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/spinlock.h>
+
+static void __native_queued_spin_unlock(struct qspinlock *lock)
+{
+	native_queued_spin_unlock(lock);
+}
+
+static void __native_wait(u8 *ptr, u8 val, int cpu)
+{
+}
+
+static void __native_kick(int cpu)
+{
+}
+
+static void __pv_wait(u8 *ptr, u8 val, int cpu)
+{
+	HMT_low();
+	__spin_yield_cpu(cpu);
+	HMT_medium();
+}
+
+static void __pv_kick(int cpu)
+{
+	__spin_wake_cpu(cpu);
+}
+
+struct pv_lock_ops pv_lock_op = {
+	.lock = native_queued_spin_lock_slowpath,
+	.unlock = __native_queued_spin_unlock,
+	.wait = __native_wait,
+	.kick = __native_kick,
+};
+EXPORT_SYMBOL(pv_lock_op);
+
+void __init pv_lock_init(void)
+{
+	if (SHARED_PROCESSOR) {
+		__pv_init_lock_hash();
+		pv_lock_op.lock = __pv_queued_spin_lock_slowpath;
+		pv_lock_op.unlock = __pv_queued_spin_unlock;
+		pv_lock_op.wait = __pv_wait;
+		pv_lock_op.kick = __pv_kick;
+	}
+}
diff --git a/arch/powerpc/lib/locks.c b/arch/powerpc/lib/locks.c
index f7deebd..6e9d3bb 100644
--- a/arch/powerpc/lib/locks.c
+++ b/arch/powerpc/lib/locks.c
@@ -23,6 +23,35 @@ 
 #include <asm/hvcall.h>
 #include <asm/smp.h>
 
+void __spin_yield_cpu(int cpu)
+{
+	unsigned int holder_cpu = cpu, yield_count;
+
+	if (cpu == -1) {
+		plpar_hcall_norets(H_CEDE);
+		return;
+	}
+	BUG_ON(holder_cpu >= nr_cpu_ids);
+	yield_count = be32_to_cpu(lppaca_of(holder_cpu).yield_count);
+	if ((yield_count & 1) == 0)
+		return;		/* virtual cpu is currently running */
+	rmb();
+	plpar_hcall_norets(H_CONFER,
+		get_hard_smp_processor_id(holder_cpu), yield_count);
+}
+EXPORT_SYMBOL_GPL(__spin_yield_cpu);
+
+void __spin_wake_cpu(int cpu)
+{
+	unsigned int holder_cpu = cpu;
+
+	BUG_ON(holder_cpu >= nr_cpu_ids);
+	plpar_hcall_norets(H_PROD,
+		get_hard_smp_processor_id(holder_cpu));
+}
+EXPORT_SYMBOL_GPL(__spin_wake_cpu);
+
+#ifndef CONFIG_QUEUED_SPINLOCKS
 void __spin_yield(arch_spinlock_t *lock)
 {
 	unsigned int lock_value, holder_cpu, yield_count;
@@ -42,6 +71,7 @@  void __spin_yield(arch_spinlock_t *lock)
 		get_hard_smp_processor_id(holder_cpu), yield_count);
 }
 EXPORT_SYMBOL_GPL(__spin_yield);
+#endif
 
 /*
  * Waiting for a read lock or a write lock on a rwlock...
@@ -69,6 +99,7 @@  void __rw_yield(arch_rwlock_t *rw)
 }
 #endif
 
+#ifndef CONFIG_QUEUED_SPINLOCKS
 void arch_spin_unlock_wait(arch_spinlock_t *lock)
 {
 	smp_mb();
@@ -84,3 +115,4 @@  void arch_spin_unlock_wait(arch_spinlock_t *lock)
 }
 
 EXPORT_SYMBOL(arch_spin_unlock_wait);
+#endif
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index 6e944fc..c9f056e 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -547,6 +547,11 @@  static void __init pSeries_setup_arch(void)
 				"%ld\n", rc);
 		}
 	}
+
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+	pv_lock_init();
+#endif
+
 }
 
 static int __init pSeries_init_panel(void)