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From: "Radim Krčmář" <rkrcmar@redhat.com>
To: David Hildenbrand <david@redhat.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
	Paolo Bonzini <pbonzini@redhat.com>,
	Andrew Jones <drjones@redhat.com>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Cornelia Huck <cornelia.huck@de.ibm.com>,
	James Hogan <james.hogan@imgtec.com>,
	Paul Mackerras <paulus@ozlabs.org>,
	Christoffer Dall <christoffer.dall@linaro.org>
Subject: Re: [PATCH v2 2/5] KVM: add KVM request variants without barrier
Date: Wed, 1 Mar 2017 17:58:02 +0100	[thread overview]
Message-ID: <20170301165801.GC20547@potion> (raw)
In-Reply-To: <969967af-8acd-4c63-ee69-a453112d8434@redhat.com>

2017-02-27 11:18+0100, David Hildenbrand:
> Am 27.02.2017 um 11:02 schrieb David Hildenbrand:
>> Am 24.02.2017 um 20:49 schrieb Radim Krčmář:
>>> The leading underscores denote that the call is just a bitop wrapper.
>> 
>> Actually, the leading underscore is misleading
>> 
>> If we want to match the semantics of set/test/clear_bit, using a leading
>> underscore might feel like using the non-atomic variants like
>> __clear_bit and friends.
>> 
>> I'd prefer to simply drop the underscore.
>> 
> 
> Okay, this is not really possible for __kvm_request_set(). Hm.....

Yeah, requests are always atomic, but have some extra cruft on top of
bit operations and underscores are similar in the sense of doing less
that the non-underscored version.  Also, the underscores were something
to make its use look undesirable in the code.

kvm_request_set and kvm_request_test_and_clear use a barrier and
kvm_request_test could be expected to do so as well.

I think that a barrier makes no sense in kvm_request_clear, but called
it with underscores for consistency with others and also because I think
that some callers of could use a second thought.

  reply	other threads:[~2017-03-01 16:59 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-24 19:49 [PATCH v2 0/5] KVM: rename and encapsulate vcpu->requests API Radim Krčmář
2017-02-24 19:49 ` [PATCH v2 1/5] KVM: rename API for requests to match bit operations Radim Krčmář
2017-02-27  9:54   ` David Hildenbrand
2017-03-01 16:37     ` Radim Krčmář
2017-02-24 19:49 ` [PATCH v2 2/5] KVM: add KVM request variants without barrier Radim Krčmář
2017-02-27 10:02   ` David Hildenbrand
2017-02-27 10:18     ` David Hildenbrand
2017-03-01 16:58       ` Radim Krčmář [this message]
2017-02-28  7:34   ` Peter Xu
2017-02-28  7:40     ` Peter Xu
2017-03-01 17:02       ` Radim Krčmář
2017-03-02  1:15         ` Peter Xu
2017-03-02  2:26           ` Peter Xu
2017-02-24 19:50 ` [PATCH v2 3/5] KVM: add kvm_request_pending Radim Krčmář
2017-02-27 10:02   ` David Hildenbrand
2017-02-24 19:50 ` [PATCH v2 4/5] KVM: MIPS: remove useless kvm_request_clear Radim Krčmář
2017-02-27  8:45   ` Andrew Jones
2017-02-27 10:03     ` David Hildenbrand
2017-02-28 11:29       ` James Hogan
2017-03-01 17:04         ` Radim Krčmář
2017-02-24 19:50 ` [PATCH v2 5/5] KVM: optimize kvm_make_all_cpus_request Radim Krčmář
2017-02-27  8:47 ` [PATCH v2 0/5] KVM: rename and encapsulate vcpu->requests API Andrew Jones

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