Re: [PATCH v6 02/11] locking/osq: Drop the overload of osq_lock()

From	Davidlohr Bueso <dave@stgolabs.net>
Newsgroups	linux.kernel
Subject	Re: [PATCH v6 02/11] locking/osq: Drop the overload of osq_lock()
Date	2016-10-29 19:00 +0200
Message-ID	<sxF97-Dc-9@gated-at.bofh.it> (permalink)
References	<sx6XL-3pw-3@gated-at.bofh.it> <sx6XL-3pw-15@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Fri, 28 Oct 2016, Pan Xinhui wrote:
> 		/*
> 		 * If we need to reschedule bail... so we can block.
>+		 * Use vcpu_is_preempted to detech lock holder preemption issue
                                            ^^ detect
>+		 * and break. 

Could you please remove the rest of this comment? Its just noise to point out
that vcpu_is_preempted is a macro defined by arch/false. This is standard protocol
in the kernel.

Same goes for all locks you change with this.

Thanks,
Davidlohr

>                * vcpu_is_preempted is a macro defined by false if
>+		 * arch does not support vcpu preempted check,
> 		 */
>-		if (need_resched())
>+		if (need_resched() || vcpu_is_preempted(node_cpu(node->prev)))
> 			goto unqueue;
>
> 		cpu_relax_lowlatency();
>-- 
>2.4.11
>

Thread

[PATCH v6 00/11] implement vcpu preempted check  Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-10-28 06:30 +0200
  [PATCH v6 06/11] x86, paravirt: Add interface to support kvm/xen vcpu preempted check Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-10-28 06:30 +0200
  [PATCH v6 05/11] s390/spinlock: Provide vcpu_is_preempted Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-10-28 06:30 +0200
  [PATCH v6 08/11] x86, kvm/x86.c: support vcpu preempted check Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-10-28 06:30 +0200
  [PATCH v6 03/11] kernel/locking: Drop the overload of {mutex,rwsem}_spin_on_owner Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-10-28 06:30 +0200
  [PATCH v6 10/11] x86, xen: support vcpu preempted check Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-10-28 06:30 +0200
    Re: [Xen-devel] [PATCH v6 10/11] x86, xen: support vcpu preempted  check Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> - 2016-10-28 21:50 +0200
  [PATCH v6 11/11] Documentation: virtual: kvm: Support vcpu preempted check Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-10-28 06:30 +0200
  [PATCH v6 02/11] locking/osq: Drop the overload of osq_lock() Pan Xinhui <xinhui.pan@linux.vnet.ibm.com> - 2016-10-28 06:30 +0200
    Re: [PATCH v6 02/11] locking/osq: Drop the overload of osq_lock() Davidlohr Bueso <dave@stgolabs.net> - 2016-10-29 19:00 +0200
  Re: [PATCH v6 00/11] implement vcpu preempted check Paolo Bonzini <pbonzini@redhat.com> - 2016-10-28 12:00 +0200
  Re: [Xen-devel] [PATCH v6 00/11] implement vcpu preempted check Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> - 2016-10-28 21:50 +0200

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