From: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
virtualization@lists.linux-foundation.org
Cc: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au,
peterz@infradead.org, mingo@redhat.com,
paulmck@linux.vnet.ibm.com, jeremy@goop.org, chrisw@sous-sol.org,
akataria@vmware.com, rusty@rustcorp.com.au,
Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Subject: [PATCH v3 3/6] powerpc: lib/locks.c: Add cpu yield/wake helper function
Date: Wed, 25 May 2016 16:18:06 +0800 [thread overview]
Message-ID: <1464164289-6124-4-git-send-email-xinhui.pan@linux.vnet.ibm.com> (raw)
In-Reply-To: <1464164289-6124-1-git-send-email-xinhui.pan@linux.vnet.ibm.com>
pv-qspinlock core has pv_wait/pv_kick which will give a better
performace by yielding and kicking cpu at some cases.
lets support them by adding two corresponding helper functions.
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
---
arch/powerpc/include/asm/spinlock.h | 4 ++++
arch/powerpc/lib/locks.c | 33 +++++++++++++++++++++++++++++++++
2 files changed, 37 insertions(+)
diff --git a/arch/powerpc/include/asm/spinlock.h b/arch/powerpc/include/asm/spinlock.h
index 4359ee6..3b65372 100644
--- a/arch/powerpc/include/asm/spinlock.h
+++ b/arch/powerpc/include/asm/spinlock.h
@@ -56,9 +56,13 @@
/* 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
diff --git a/arch/powerpc/lib/locks.c b/arch/powerpc/lib/locks.c
index a9ebd71..3a58834 100644
--- a/arch/powerpc/lib/locks.c
+++ b/arch/powerpc/lib/locks.c
@@ -23,6 +23,39 @@
#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_CONFER, -1, 0);
+ return;
+ }
+ BUG_ON(holder_cpu >= nr_cpu_ids);
+ yield_count = be32_to_cpu(lppaca_of(holder_cpu).yield_count);
+ if ((yield_count & 1) == 0) {
+ /* if target cpu is running, confer slices to lpar*/
+ plpar_hcall_norets(H_CONFER, -1, 0);
+ return;
+ }
+ 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, yield_count;
+
+ 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 */
+ 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)
{
--
1.9.1
next prev parent reply other threads:[~2016-05-25 8:21 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-25 8:18 [PATCH v3 0/6] powerpc use pv-qpsinlock as the default spinlock implemention Pan Xinhui
2016-05-25 8:18 ` [PATCH v3 1/6] qspinlock: powerpc support qspinlock Pan Xinhui
2016-05-25 8:18 ` [PATCH v3 2/6] powerpc: pseries/Kconfig: Add qspinlock build config Pan Xinhui
2016-05-25 8:18 ` Pan Xinhui [this message]
2016-05-25 8:18 ` [PATCH v3 4/6] pv-qspinlock: powerpc support pv-qspinlock Pan Xinhui
2016-05-25 8:18 ` [PATCH v3 5/6] pv-qspinlock: use cmpxchg_release in __pv_queued_spin_unlock Pan Xinhui
2016-05-26 16:47 ` Peter Zijlstra
2016-05-26 16:57 ` Peter Zijlstra
2016-05-27 10:34 ` xinhui
2016-05-25 8:18 ` [PATCH v3 6/6] powerpc: pseries: Add pv-qspinlock build config/make Pan Xinhui
2016-05-26 16:50 ` [PATCH v3 0/6] powerpc use pv-qpsinlock as the default spinlock implemention Peter Zijlstra
2016-05-27 10:52 ` xinhui
2016-05-26 16:54 ` Peter Zijlstra
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