Re: [PATCH 6/8] powerpc/pseries: implement paravirt qspinlocks for SPLPAR
On 7/2/20 12:15 PM, kernel test robot wrote:
Hi Nicholas,
I love your patch! Yet something to improve:
[auto build test ERROR on powerpc/next]
[also build test ERROR on tip/locking/core v5.8-rc3 next-20200702]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use as documented in
https://git-scm.com/docs/git-format-patch]
url:
https://github.com/0day-ci/linux/commits/Nicholas-Piggin/powerpc-queued-spinlocks-and-rwlocks/20200702-155158
base: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-allyesconfig (attached as .config)
compiler: powerpc64-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget
https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross
ARCH=powerpc
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot
All errors (new ones prefixed by >>):
kernel/locking/lock_events.c:61:16: warning: no previous prototype for
'lockevent_read' [-Wmissing-prototypes]
61 | ssize_t __weak lockevent_read(struct file *file, char __user
*user_buf,
|^~
kernel/locking/lock_events.c: In function 'skip_lockevent':
kernel/locking/lock_events.c:126:12: error: implicit declaration of function
'pv_is_native_spin_unlock' [-Werror=implicit-function-declaration]
126 | pv_on = !pv_is_native_spin_unlock();
|^~~~
cc1: some warnings being treated as errors
vim +/pv_is_native_spin_unlock +126 kernel/locking/lock_events.c
I think you will need to add the following into
arch/powerpc/include/asm/qspinlock_paravirt.h:
static inline pv_is_native_spin_unlock(void)
{
return !is_shared_processor();
}
Cheers,
Longman
Re: [PATCH 6/8] powerpc/pseries: implement paravirt qspinlocks for SPLPAR
On 7/2/20 3:48 AM, Nicholas Piggin wrote:
Signed-off-by: Nicholas Piggin
---
arch/powerpc/include/asm/paravirt.h | 23
arch/powerpc/include/asm/qspinlock.h | 55 +++
arch/powerpc/include/asm/qspinlock_paravirt.h | 5 ++
arch/powerpc/platforms/pseries/Kconfig| 5 ++
arch/powerpc/platforms/pseries/setup.c| 6 +-
include/asm-generic/qspinlock.h | 2 +
6 files changed, 95 insertions(+), 1 deletion(-)
create mode 100644 arch/powerpc/include/asm/qspinlock_paravirt.h
diff --git a/arch/powerpc/include/asm/paravirt.h
b/arch/powerpc/include/asm/paravirt.h
index 7a8546660a63..5fae9dfa6fe9 100644
--- a/arch/powerpc/include/asm/paravirt.h
+++ b/arch/powerpc/include/asm/paravirt.h
@@ -29,6 +29,16 @@ static inline void yield_to_preempted(int cpu, u32
yield_count)
{
plpar_hcall_norets(H_CONFER, get_hard_smp_processor_id(cpu),
yield_count);
}
+
+static inline void prod_cpu(int cpu)
+{
+ plpar_hcall_norets(H_PROD, get_hard_smp_processor_id(cpu));
+}
+
+static inline void yield_to_any(void)
+{
+ plpar_hcall_norets(H_CONFER, -1, 0);
+}
#else
static inline bool is_shared_processor(void)
{
@@ -45,6 +55,19 @@ static inline void yield_to_preempted(int cpu, u32
yield_count)
{
___bad_yield_to_preempted(); /* This would be a bug */
}
+
+extern void ___bad_yield_to_any(void);
+static inline void yield_to_any(void)
+{
+ ___bad_yield_to_any(); /* This would be a bug */
+}
+
+extern void ___bad_prod_cpu(void);
+static inline void prod_cpu(int cpu)
+{
+ ___bad_prod_cpu(); /* This would be a bug */
+}
+
#endif
#define vcpu_is_preempted vcpu_is_preempted
diff --git a/arch/powerpc/include/asm/qspinlock.h
b/arch/powerpc/include/asm/qspinlock.h
index f84da77b6bb7..997a9a32df77 100644
--- a/arch/powerpc/include/asm/qspinlock.h
+++ b/arch/powerpc/include/asm/qspinlock.h
@@ -3,9 +3,36 @@
#define _ASM_POWERPC_QSPINLOCK_H
#include
+#include
#define _Q_PENDING_LOOPS (1 << 9) /* not tuned */
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+extern void native_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
+extern void __pv_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
+
+static __always_inline void queued_spin_lock_slowpath(struct qspinlock *lock,
u32 val)
+{
+ if (!is_shared_processor())
+ native_queued_spin_lock_slowpath(lock, val);
+ else
+ __pv_queued_spin_lock_slowpath(lock, val);
+}
You may need to match the use of __pv_queued_spin_lock_slowpath() with
the corresponding __pv_queued_spin_unlock(), e.g.
#define queued_spin_unlock queued_spin_unlock
static inline queued_spin_unlock(struct qspinlock *lock)
{
if (!is_shared_processor())
smp_store_release(&lock->locked, 0);
else
__pv_queued_spin_unlock(lock);
}
Otherwise, pv_kick() will never be called.
Cheers,
Longman
Re: [PATCH 6/8] powerpc/pseries: implement paravirt qspinlocks for SPLPAR
Hi Nicholas,
I love your patch! Yet something to improve:
[auto build test ERROR on powerpc/next]
[also build test ERROR on tip/locking/core v5.8-rc3 next-20200702]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use as documented in
https://git-scm.com/docs/git-format-patch]
url:
https://github.com/0day-ci/linux/commits/Nicholas-Piggin/powerpc-queued-spinlocks-and-rwlocks/20200702-155158
base: https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
config: powerpc-allyesconfig (attached as .config)
compiler: powerpc64-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
wget
https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O
~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross
ARCH=powerpc
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot
All errors (new ones prefixed by >>):
kernel/locking/lock_events.c:61:16: warning: no previous prototype for
'lockevent_read' [-Wmissing-prototypes]
61 | ssize_t __weak lockevent_read(struct file *file, char __user
*user_buf,
|^~
kernel/locking/lock_events.c: In function 'skip_lockevent':
>> kernel/locking/lock_events.c:126:12: error: implicit declaration of function
>> 'pv_is_native_spin_unlock' [-Werror=implicit-function-declaration]
126 | pv_on = !pv_is_native_spin_unlock();
|^~~~
cc1: some warnings being treated as errors
vim +/pv_is_native_spin_unlock +126 kernel/locking/lock_events.c
fb346fd9fc081c Waiman Long 2019-04-04 57
fb346fd9fc081c Waiman Long 2019-04-04 58 /*
fb346fd9fc081c Waiman Long 2019-04-04 59 * The lockevent_read() function
can be overridden.
fb346fd9fc081c Waiman Long 2019-04-04 60 */
fb346fd9fc081c Waiman Long 2019-04-04 @61 ssize_t __weak
lockevent_read(struct file *file, char __user *user_buf,
fb346fd9fc081c Waiman Long 2019-04-04 62size_t
count, loff_t *ppos)
fb346fd9fc081c Waiman Long 2019-04-04 63 {
fb346fd9fc081c Waiman Long 2019-04-04 64 char buf[64];
fb346fd9fc081c Waiman Long 2019-04-04 65 int cpu, id, len;
fb346fd9fc081c Waiman Long 2019-04-04 66 u64 sum = 0;
fb346fd9fc081c Waiman Long 2019-04-04 67
fb346fd9fc081c Waiman Long 2019-04-04 68 /*
fb346fd9fc081c Waiman Long 2019-04-04 69 * Get the counter ID stored in
file->f_inode->i_private
fb346fd9fc081c Waiman Long 2019-04-04 70 */
fb346fd9fc081c Waiman Long 2019-04-04 71 id =
(long)file_inode(file)->i_private;
fb346fd9fc081c Waiman Long 2019-04-04 72
fb346fd9fc081c Waiman Long 2019-04-04 73 if (id >= lockevent_num)
fb346fd9fc081c Waiman Long 2019-04-04 74 return -EBADF;
fb346fd9fc081c Waiman Long 2019-04-04 75
fb346fd9fc081c Waiman Long 2019-04-04 76 for_each_possible_cpu(cpu)
fb346fd9fc081c Waiman Long 2019-04-04 77 sum +=
per_cpu(lockevents[id], cpu);
fb346fd9fc081c Waiman Long 2019-04-04 78 len = snprintf(buf, sizeof(buf)
- 1, "%llu\n", sum);
fb346fd9fc081c Waiman Long 2019-04-04 79
fb346fd9fc081c Waiman Long 2019-04-04 80 return
simple_read_from_buffer(user_buf, count, ppos, buf, len);
fb346fd9fc081c Waiman Long 2019-04-04 81 }
fb346fd9fc081c Waiman Long 2019-04-04 82
fb346fd9fc081c Waiman Long 2019-04-04 83 /*
fb346fd9fc081c Waiman Long 2019-04-04 84 * Function to handle write request
fb346fd9fc081c Waiman Long 2019-04-04 85 *
fb346fd9fc081c Waiman Long 2019-04-04 86 * When idx = reset_cnts, reset all
the counts.
fb346fd9fc081c Waiman Long 2019-04-04 87 */
fb346fd9fc081c Waiman Long 2019-04-04 88 static ssize_t
lockevent_write(struct file *file, const char __user *user_buf,
fb346fd9fc081c Waiman Long 2019-04-04 89 size_t
count, loff_t *ppos)
fb346fd9fc081c Waiman Long 2019-04-04 90 {
fb346fd9fc081c Waiman Long 2019-04-04 91 int cpu;
fb346fd9fc081c Waiman Long 2019-04-04 92
fb346fd9fc081c Waiman Long 2019-04-04 93 /*
fb346fd9fc081c Waiman Long 2019-04-04 94 * Get the counter ID stored in
file->f_inode->i_private
fb346fd9fc081c Waiman Long 2019-04-04 95 */
fb346fd9fc081c Waiman Long 2019-04-04 96 if
((long)file_inode(file)->i_private != LOCKEVENT_reset_cnts)
fb346fd9fc081c Waiman Long 2019-04-04 97 return count;
fb346fd9fc081c Waiman Long 2019-04-04 98
fb346fd9fc081c Waiman Long 2019-04-04 99 for_each_possible_cpu(cpu) {
fb346fd9fc081c Waiman Long 2019-04-04 100 int i;
fb346fd9fc081c Waiman Long 2019-04-04 101 unsigned long *ptr =
per_cpu_ptr(lockevents, cpu);
fb346fd9fc081c Waiman Long 2019-04-04 102
fb346fd9fc081c Waiman Long 2019-04-04 103
[PATCH 6/8] powerpc/pseries: implement paravirt qspinlocks for SPLPAR
Signed-off-by: Nicholas Piggin
---
arch/powerpc/include/asm/paravirt.h | 23
arch/powerpc/include/asm/qspinlock.h | 55 +++
arch/powerpc/include/asm/qspinlock_paravirt.h | 5 ++
arch/powerpc/platforms/pseries/Kconfig| 5 ++
arch/powerpc/platforms/pseries/setup.c| 6 +-
include/asm-generic/qspinlock.h | 2 +
6 files changed, 95 insertions(+), 1 deletion(-)
create mode 100644 arch/powerpc/include/asm/qspinlock_paravirt.h
diff --git a/arch/powerpc/include/asm/paravirt.h
b/arch/powerpc/include/asm/paravirt.h
index 7a8546660a63..5fae9dfa6fe9 100644
--- a/arch/powerpc/include/asm/paravirt.h
+++ b/arch/powerpc/include/asm/paravirt.h
@@ -29,6 +29,16 @@ static inline void yield_to_preempted(int cpu, u32
yield_count)
{
plpar_hcall_norets(H_CONFER, get_hard_smp_processor_id(cpu),
yield_count);
}
+
+static inline void prod_cpu(int cpu)
+{
+ plpar_hcall_norets(H_PROD, get_hard_smp_processor_id(cpu));
+}
+
+static inline void yield_to_any(void)
+{
+ plpar_hcall_norets(H_CONFER, -1, 0);
+}
#else
static inline bool is_shared_processor(void)
{
@@ -45,6 +55,19 @@ static inline void yield_to_preempted(int cpu, u32
yield_count)
{
___bad_yield_to_preempted(); /* This would be a bug */
}
+
+extern void ___bad_yield_to_any(void);
+static inline void yield_to_any(void)
+{
+ ___bad_yield_to_any(); /* This would be a bug */
+}
+
+extern void ___bad_prod_cpu(void);
+static inline void prod_cpu(int cpu)
+{
+ ___bad_prod_cpu(); /* This would be a bug */
+}
+
#endif
#define vcpu_is_preempted vcpu_is_preempted
diff --git a/arch/powerpc/include/asm/qspinlock.h
b/arch/powerpc/include/asm/qspinlock.h
index f84da77b6bb7..997a9a32df77 100644
--- a/arch/powerpc/include/asm/qspinlock.h
+++ b/arch/powerpc/include/asm/qspinlock.h
@@ -3,9 +3,36 @@
#define _ASM_POWERPC_QSPINLOCK_H
#include
+#include
#define _Q_PENDING_LOOPS (1 << 9) /* not tuned */
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+extern void native_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
+extern void __pv_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
+
+static __always_inline void queued_spin_lock_slowpath(struct qspinlock *lock,
u32 val)
+{
+ if (!is_shared_processor())
+ native_queued_spin_lock_slowpath(lock, val);
+ else
+ __pv_queued_spin_lock_slowpath(lock, val);
+}
+#else
+extern void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
+#endif
+
+static __always_inline void queued_spin_lock(struct qspinlock *lock)
+{
+ u32 val = 0;
+
+ if (likely(atomic_try_cmpxchg_acquire(&lock->val, &val, _Q_LOCKED_VAL)))
+ return;
+
+ queued_spin_lock_slowpath(lock, val);
+}
+#define queued_spin_lock queued_spin_lock
+
#define smp_mb__after_spinlock() smp_mb()
static __always_inline int queued_spin_is_locked(struct qspinlock *lock)
@@ -15,6 +42,34 @@ static __always_inline int queued_spin_is_locked(struct
qspinlock *lock)
}
#define queued_spin_is_locked queued_spin_is_locked
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+#define SPIN_THRESHOLD (1<<15) /* not tuned */
+
+static __always_inline void pv_wait(u8 *ptr, u8 val)
+{
+ if (*ptr != val)
+ return;
+ yield_to_any();
+ /*
+* We could pass in a CPU here if waiting in the queue and yield to
+* the previous CPU in the queue.
+*/
+}
+
+static __always_inline void pv_kick(int cpu)
+{
+ prod_cpu(cpu);
+}
+
+extern void __pv_init_lock_hash(void);
+
+static inline void pv_spinlocks_init(void)
+{
+ __pv_init_lock_hash();
+}
+
+#endif
+
#include
#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 ..6dbdb8a4f84f
--- /dev/null
+++ b/arch/powerpc/include/asm/qspinlock_paravirt.h
@@ -0,0 +1,5 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+#ifndef __ASM_QSPINLOCK_PARAVIRT_H
+#define __ASM_QSPINLOCK_PARAVIRT_H
+
+#endif /* __ASM_QSPINLOCK_PARAVIRT_H */
diff --git a/arch/powerpc/platforms/pseries/Kconfig
b/arch/powerpc/platforms/pseries/Kconfig
index 24c18362e5ea..756e727b383f 100644
--- a/arch/powerpc/platforms/pseries/Kconfig
+++ b/arch/powerpc/platforms/pseries/Kconfig
@@ -25,9 +25,14 @@ config PPC_PSERIES
select SWIOTLB
default y
+config PARAVIRT_SPINLOCKS
+ bool
+ default n
+
config PPC_SPLPAR
depends on PPC_PSERIES
bool "Support for shared-processor logical partitions"
+ select PARAVIRT_SPINLOCKS if PPC_QUEUED_SPINLOCKS
help
Enabling this option will make the kernel run more efficiently
on logically-partitioned pSeries systems which use shared
diff --git a/arch/powerpc/platforms/pseries/setup.c
b/arch/powerpc/platforms/pseries/setup.c
index 2db8469e475f..747a203d9453 100644
--- a/arch/powerpc/platforms/pse
