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,
linux-s390@vger.kernel.org,
xen-devel-request@lists.xenproject.org, kvm@vger.kernel.org,
xen-devel@lists.xenproject.org, x86@kernel.org
Cc: benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au,
mingo@redhat.com, peterz@infradead.org,
paulmck@linux.vnet.ibm.com, will.deacon@arm.com,
kernellwp@gmail.com, jgross@suse.com, pbonzini@redhat.com,
bsingharora@gmail.com, boqun.feng@gmail.com,
borntraeger@de.ibm.com, rkrcmar@redhat.com,
David.Laight@ACULAB.COM, dave@stgolabs.net,
konrad.wilk@oracle.com,
Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Subject: [PATCH v7 06/11] x86, paravirt: Add interface to support kvm/xen vcpu preempted check
Date: Wed, 2 Nov 2016 05:08:33 -0400 [thread overview]
Message-ID: <1478077718-37424-7-git-send-email-xinhui.pan@linux.vnet.ibm.com> (raw)
In-Reply-To: <1478077718-37424-1-git-send-email-xinhui.pan@linux.vnet.ibm.com>
This is to fix some lock holder preemption issues. Some other locks
implementation do a spin loop before acquiring the lock itself.
Currently kernel has an interface of bool vcpu_is_preempted(int cpu). It
takes the cpu as parameter and return true if the cpu is preempted.
Then kernel can break the spin loops upon the retval of
vcpu_is_preempted.
As kernel has used this interface, So lets support it.
To deal with kernel and kvm/xen, add vcpu_is_preempted into struct
pv_lock_ops.
Then kvm or xen could provide their own implementation to support
vcpu_is_preempted.
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
---
arch/x86/include/asm/paravirt_types.h | 2 ++
arch/x86/include/asm/spinlock.h | 8 ++++++++
arch/x86/kernel/paravirt-spinlocks.c | 6 ++++++
3 files changed, 16 insertions(+)
diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 0f400c0..38c3bb7 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -310,6 +310,8 @@ struct pv_lock_ops {
void (*wait)(u8 *ptr, u8 val);
void (*kick)(int cpu);
+
+ bool (*vcpu_is_preempted)(int cpu);
};
/* This contains all the paravirt structures: we get a convenient
diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h
index 921bea7..0526f59 100644
--- a/arch/x86/include/asm/spinlock.h
+++ b/arch/x86/include/asm/spinlock.h
@@ -26,6 +26,14 @@
extern struct static_key paravirt_ticketlocks_enabled;
static __always_inline bool static_key_false(struct static_key *key);
+#ifdef CONFIG_PARAVIRT_SPINLOCKS
+#define vcpu_is_preempted vcpu_is_preempted
+static inline bool vcpu_is_preempted(int cpu)
+{
+ return pv_lock_ops.vcpu_is_preempted(cpu);
+}
+#endif
+
#include <asm/qspinlock.h>
/*
diff --git a/arch/x86/kernel/paravirt-spinlocks.c b/arch/x86/kernel/paravirt-spinlocks.c
index 2c55a00..2f204dd 100644
--- a/arch/x86/kernel/paravirt-spinlocks.c
+++ b/arch/x86/kernel/paravirt-spinlocks.c
@@ -21,12 +21,18 @@ bool pv_is_native_spin_unlock(void)
__raw_callee_save___native_queued_spin_unlock;
}
+static bool native_vcpu_is_preempted(int cpu)
+{
+ return 0;
+}
+
struct pv_lock_ops pv_lock_ops = {
#ifdef CONFIG_SMP
.queued_spin_lock_slowpath = native_queued_spin_lock_slowpath,
.queued_spin_unlock = PV_CALLEE_SAVE(__native_queued_spin_unlock),
.wait = paravirt_nop,
.kick = paravirt_nop,
+ .vcpu_is_preempted = native_vcpu_is_preempted,
#endif /* SMP */
};
EXPORT_SYMBOL(pv_lock_ops);
--
2.4.11
next prev parent reply other threads:[~2016-11-02 5:14 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-02 9:08 [PATCH v7 00/11] implement vcpu preempted check Pan Xinhui
2016-11-02 9:08 ` [PATCH v7 01/11] kernel/sched: introduce vcpu preempted check interface Pan Xinhui
2016-11-22 12:31 ` [tip:locking/core] sched/core: Introduce the vcpu_is_preempted(cpu) interface tip-bot for Pan Xinhui
2016-11-02 9:08 ` [PATCH v7 02/11] locking/osq: Drop the overload of osq_lock() Pan Xinhui
2016-11-22 12:36 ` [tip:locking/core] locking/osq: Break out of spin-wait busy waiting loop for a preempted vCPU in osq_lock() tip-bot for Pan Xinhui
2016-11-02 9:08 ` [PATCH v7 03/11] kernel/locking: Drop the overload of {mutex,rwsem}_spin_on_owner Pan Xinhui
2016-11-22 12:36 ` [tip:locking/core] locking/mutex: Break out of expensive busy-loop on {mutex,rwsem}_spin_on_owner() when owner vCPU is preempted tip-bot for Pan Xinhui
2016-11-02 9:08 ` [PATCH v7 04/11] powerpc/spinlock: support vcpu preempted check Pan Xinhui
2016-11-22 12:32 ` [tip:locking/core] locking/core, powerpc: Implement vcpu_is_preempted(cpu) tip-bot for Pan Xinhui
2016-11-02 9:08 ` [PATCH v7 05/11] s390/spinlock: Provide vcpu_is_preempted Pan Xinhui
2016-11-22 12:32 ` [tip:locking/core] locking/spinlocks, s390: Implement vcpu_is_preempted(cpu) tip-bot for Christian Borntraeger
2016-11-02 9:08 ` Pan Xinhui [this message]
2016-11-15 15:47 ` [PATCH v7 06/11] x86, paravirt: Add interface to support kvm/xen vcpu preempted check Peter Zijlstra
2016-11-16 4:19 ` Pan Xinhui
2016-11-16 10:23 ` Peter Zijlstra
2016-11-16 11:29 ` Christian Borntraeger
2016-11-16 11:43 ` Peter Zijlstra
2016-11-17 5:16 ` Pan Xinhui
2016-11-22 12:33 ` [tip:locking/core] locking/core, x86/paravirt: Implement vcpu_is_preempted(cpu) for KVM and Xen guests tip-bot for Pan Xinhui
2016-11-02 9:08 ` [PATCH v7 07/11] KVM: Introduce kvm_write_guest_offset_cached Pan Xinhui
2016-11-22 12:33 ` [tip:locking/core] kvm: Introduce kvm_write_guest_offset_cached() tip-bot for Pan Xinhui
2016-11-02 9:08 ` [PATCH v7 08/11] x86, kvm/x86.c: support vcpu preempted check Pan Xinhui
2016-11-22 12:34 ` [tip:locking/core] x86/kvm: Support the vCPU preemption check tip-bot for Pan Xinhui
2016-12-19 11:42 ` [PATCH v7 08/11] x86, kvm/x86.c: support vcpu preempted check Andrea Arcangeli
2016-12-19 13:56 ` Pan Xinhui
2016-12-19 14:39 ` Paolo Bonzini
2016-11-02 9:08 ` [PATCH v7 09/11] x86, kernel/kvm.c: " Pan Xinhui
2016-11-22 12:34 ` [tip:locking/core] x86/kvm: Support the vCPU preemption check tip-bot for Pan Xinhui
2016-11-02 9:08 ` [PATCH v7 10/11] x86, xen: support vcpu preempted check Pan Xinhui
2016-11-22 12:35 ` [tip:locking/core] x86/xen: Support the vCPU preemption check tip-bot for Juergen Gross
2016-11-02 9:08 ` [PATCH v7 11/11] Documentation: virtual: kvm: Support vcpu preempted check Pan Xinhui
2016-11-22 12:35 ` [tip:locking/core] Documentation/virtual/kvm: Support the vCPU preemption check tip-bot for Pan Xinhui
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