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
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,
Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Subject: [PATCH v5 1/9] kernel/sched: introduce vcpu preempted check interface
Date: Thu, 20 Oct 2016 17:27:46 -0400 [thread overview]
Message-ID: <1476998874-2089-2-git-send-email-xinhui.pan@linux.vnet.ibm.com> (raw)
In-Reply-To: <1476998874-2089-1-git-send-email-xinhui.pan@linux.vnet.ibm.com>
This patch support to fix lock holder preemption issue.
For kernel users, we could use bool vcpu_is_preempted(int cpu) to detech if
one vcpu is preempted or not.
The default implementation is a macro defined by false. So compiler can
wrap it out if arch dose not support such vcpu pteempted check.
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Tested-by: Juergen Gross <jgross@suse.com>
---
include/linux/sched.h | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 348f51b..44c1ce7 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -3506,6 +3506,18 @@ static inline void set_task_cpu(struct task_struct *p, unsigned int cpu)
#endif /* CONFIG_SMP */
+/*
+ * In order to deal with a various lock holder preemption issues provide an
+ * interface to see if a vCPU is currently running or not.
+ *
+ * This allows us to terminate optimistic spin loops and block, analogous to
+ * the native optimistic spin heuristic of testing if the lock owner task is
+ * running or not.
+ */
+#ifndef vcpu_is_preempted
+#define vcpu_is_preempted(cpu) false
+#endif
+
extern long sched_setaffinity(pid_t pid, const struct cpumask *new_mask);
extern long sched_getaffinity(pid_t pid, struct cpumask *mask);
--
2.4.11
next prev parent reply other threads:[~2016-10-20 17:31 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-20 21:27 [PATCH v5 0/9] implement vcpu preempted check Pan Xinhui
2016-10-20 21:27 ` Pan Xinhui [this message]
2016-10-20 21:27 ` [PATCH v5 2/9] locking/osq: Drop the overload of osq_lock() Pan Xinhui
2016-10-20 21:27 ` [PATCH v5 3/9] kernel/locking: Drop the overload of {mutex,rwsem}_spin_on_owner Pan Xinhui
2016-10-20 21:27 ` [PATCH v5 4/9] powerpc/spinlock: support vcpu preempted check Pan Xinhui
2016-10-20 21:27 ` [PATCH v5 5/9] x86, paravirt: Add interface to support kvm/xen " Pan Xinhui
2016-10-20 21:27 ` [PATCH v5 6/9] x86, kvm: support " Pan Xinhui
2016-10-24 8:08 ` xinhui
2016-10-20 21:27 ` [PATCH v5 7/9] x86, xen: " Pan Xinhui
2016-10-21 5:08 ` Juergen Gross
2016-10-20 21:27 ` [PATCH v5 8/9] s390/spinlock: Provide vcpu_is_preempted Pan Xinhui
2016-10-20 21:27 ` [PATCH v5 9/9] Documentation: virtual: kvm: Support vcpu preempted check Pan Xinhui
2016-10-21 1:23 ` Boqun Feng
2016-10-21 11:27 ` David Laight
2016-10-21 18:39 ` rkrcmar
2016-10-24 2:46 ` xinhui
2016-10-24 14:42 ` Paolo Bonzini
2016-10-24 15:05 ` rkrcmar
2016-10-24 2:44 ` xinhui
2016-10-24 8:12 ` xinhui
2016-10-21 5:40 ` [PATCH v5 0/9] implement " Peter Zijlstra
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