From: Peter Zijlstra <peterz@infradead.org>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>,
linux-s390@vger.kernel.org, dave@stgolabs.net,
mpe@ellerman.id.au, boqun.feng@gmail.com, will.deacon@arm.com,
linux-kernel@vger.kernel.org, waiman.long@hpe.com,
virtualization@lists.linux-foundation.org, mingo@redhat.com,
paulus@samba.org, benh@kernel.crashing.org,
schwidefsky@de.ibm.com, paulmck@linux.vnet.ibm.com,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2 0/4] implement vcpu preempted check
Date: Wed, 6 Jul 2016 13:59:54 +0200 [thread overview]
Message-ID: <20160706115954.GK30921@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <14a24854-9787-e4a1-c9a8-76eba4e97301@redhat.com>
On Wed, Jul 06, 2016 at 12:44:58PM +0200, Paolo Bonzini wrote:
> > Paolo, could you help out with an (x86) KVM interface for this?
>
> If it's just for spin loops, you can check if the version field in the
> steal time structure has changed.
That would require remembering the old value, no?
That would work with a previous interface proposal, see:
http://lkml.kernel.org/r/1466937715-6683-2-git-send-email-xinhui.pan@linux.vnet.ibm.com
the vcpu_get_yield_count() thing would match that I think.
However the current proposal:
http://lkml.kernel.org/r/1467124991-13164-2-git-send-email-xinhui.pan@linux.vnet.ibm.com
dropped that in favour of only vcpu_is_preempted(), which requires being
able to tell if a (remote) vcpu is currently running or not, which iirc,
isn't possible with the steal time sequence count.
next prev parent reply other threads:[~2016-07-06 12:00 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-28 14:43 Pan Xinhui
2016-06-28 14:43 ` [PATCH v2 1/4] kernel/sched: introduce vcpu preempted check interface Pan Xinhui
2016-06-28 14:43 ` [PATCH v2 2/4] powerpc/spinlock: support vcpu preempted check Pan Xinhui
2016-07-05 9:57 ` Wanpeng Li
2016-07-06 4:58 ` xinhui
2016-07-06 6:46 ` Wanpeng Li
2016-07-06 7:58 ` Peter Zijlstra
2016-07-06 8:32 ` Wanpeng Li
2016-07-06 10:18 ` xinhui
2016-07-06 10:54 ` Balbir Singh
2016-07-15 15:35 ` Pan Xinhui
2016-06-28 14:43 ` [PATCH v2 3/4] locking/osq: Drop the overload of osq_lock() Pan Xinhui
2016-06-28 14:43 ` [PATCH v2 4/4] kernel/locking: Drop the overload of {mutex,rwsem}_spin_on_owner Pan Xinhui
2016-07-06 6:52 ` [PATCH v2 0/4] implement vcpu preempted check Peter Zijlstra
2016-07-06 7:47 ` Juergen Gross
2016-07-06 8:19 ` Peter Zijlstra
2016-07-06 8:38 ` Juergen Gross
2016-07-06 12:44 ` Paolo Bonzini
2016-07-06 16:56 ` Christian Borntraeger
2016-07-06 10:05 ` xinhui
2016-07-06 10:44 ` Paolo Bonzini
2016-07-06 11:59 ` Peter Zijlstra [this message]
2016-07-06 12:08 ` Wanpeng Li
2016-07-06 12:28 ` Paolo Bonzini
2016-07-06 13:03 ` Wanpeng Li
2016-07-07 8:48 ` Wanpeng Li
2016-07-07 9:42 ` Peter Zijlstra
2016-07-07 10:12 ` Wanpeng Li
2016-07-07 10:27 ` Wanpeng Li
2016-07-07 11:15 ` Peter Zijlstra
2016-07-07 11:08 ` Peter Zijlstra
2016-07-07 11:09 ` Peter Zijlstra
2016-07-07 11:21 ` Peter Zijlstra
2016-07-11 15:10 ` Waiman Long
2016-07-12 4:16 ` Juergen Gross
2016-07-12 18:16 ` Waiman Long
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