From: Nicholas Piggin <npiggin@gmail.com>
Cc: Nicholas Piggin <npiggin@gmail.com>,
Will Deacon <will@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Boqun Feng <boqun.feng@gmail.com>, Ingo Molnar <mingo@redhat.com>,
Waiman Long <longman@redhat.com>,
Anton Blanchard <anton@ozlabs.org>,
linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
virtualization@lists.linux-foundation.org,
kvm-ppc@vger.kernel.org, linux-arch@vger.kernel.org
Subject: [PATCH v2 5/6] powerpc/pseries: implement paravirt qspinlocks for SPLPAR
Date: Fri, 3 Jul 2020 17:35:15 +1000 [thread overview]
Message-ID: <20200703073516.1354108-6-npiggin@gmail.com> (raw)
Message-ID: <20200703073515.7p9i44bMKGUGtkI3GphBZ1QnFzrIj1IDgJ3qMQlqo3c@z> (raw)
In-Reply-To: <20200703073516.1354108-1-npiggin@gmail.com>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
arch/powerpc/include/asm/paravirt.h | 28 ++++++++++
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, 100 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..f2d51f929cf5 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
@@ -57,5 +80,10 @@ static inline bool vcpu_is_preempted(int cpu)
return false;
}
+static inline bool pv_is_native_spin_unlock(void)
+{
+ return !is_shared_processor();
+}
+
#endif /* __KERNEL__ */
#endif /* __ASM_PARAVIRT_H */
diff --git a/arch/powerpc/include/asm/qspinlock.h b/arch/powerpc/include/asm/qspinlock.h
index c49e33e24edd..0960a0de2467 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 <asm-generic/qspinlock_types.h>
+#include <asm/paravirt.h>
#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)
@@ -20,6 +47,34 @@ 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 <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 000000000000..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/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -771,8 +771,12 @@ static void __init pSeries_setup_arch(void)
if (firmware_has_feature(FW_FEATURE_LPAR)) {
vpa_init(boot_cpuid);
- if (lppaca_shared_proc(get_lppaca()))
+ if (lppaca_shared_proc(get_lppaca())) {
static_branch_enable(&shared_processor);
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+ pv_spinlocks_init();
+#endif
+ }
ppc_md.power_save = pseries_lpar_idle;
ppc_md.enable_pmcs = pseries_lpar_enable_pmcs;
diff --git a/include/asm-generic/qspinlock.h b/include/asm-generic/qspinlock.h
index fb0a814d4395..38ca14e79a86 100644
--- a/include/asm-generic/qspinlock.h
+++ b/include/asm-generic/qspinlock.h
@@ -69,6 +69,7 @@ static __always_inline int queued_spin_trylock(struct qspinlock *lock)
extern void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
+#ifndef queued_spin_lock
/**
* queued_spin_lock - acquire a queued spinlock
* @lock: Pointer to queued spinlock structure
@@ -82,6 +83,7 @@ static __always_inline void queued_spin_lock(struct qspinlock *lock)
queued_spin_lock_slowpath(lock, val);
}
+#endif
#ifndef queued_spin_unlock
/**
--
2.23.0
next prev parent reply other threads:[~2020-07-03 7:35 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-03 7:35 [PATCH v2 0/6] powerpc: queued spinlocks and rwlocks Nicholas Piggin
2020-07-03 7:35 ` Nicholas Piggin
2020-07-03 7:35 ` [PATCH v2 1/6] powerpc/powernv: must include hvcall.h to get PAPR defines Nicholas Piggin
2020-07-03 7:35 ` Nicholas Piggin
2020-07-03 7:35 ` [PATCH v2 2/6] powerpc/pseries: move some PAPR paravirt functions to their own file Nicholas Piggin
2020-07-03 7:35 ` Nicholas Piggin
2020-07-03 7:35 ` [PATCH v2 3/6] powerpc: move spinlock implementation to simple_spinlock Nicholas Piggin
2020-07-03 7:35 ` Nicholas Piggin
2020-07-03 7:35 ` [PATCH v2 4/6] powerpc/64s: implement queued spinlocks and rwlocks Nicholas Piggin
2020-07-03 7:35 ` Nicholas Piggin [this message]
2020-07-03 7:35 ` [PATCH v2 5/6] powerpc/pseries: implement paravirt qspinlocks for SPLPAR Nicholas Piggin
2020-07-05 19:00 ` Waiman Long
2020-07-05 19:00 ` Waiman Long
2020-07-06 0:30 ` Nicholas Piggin
2020-07-06 0:30 ` Nicholas Piggin
2020-07-03 7:35 ` [PATCH v2 6/6] powerpc/qspinlock: optimised atomic_try_cmpxchg_lock that adds the lock hint Nicholas Piggin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200703073516.1354108-6-npiggin@gmail.com \
--to=npiggin@gmail.com \
--cc=anton@ozlabs.org \
--cc=boqun.feng@gmail.com \
--cc=kvm-ppc@vger.kernel.org \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=longman@redhat.com \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=virtualization@lists.linux-foundation.org \
--cc=will@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).