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From: Lai Jiangshan <jiangshanlai@gmail.com>
To: Sean Christopherson <seanjc@google.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	"open list:KERNEL VIRTUAL MACHINE FOR MIPS (KVM/mips)" 
	<kvm@vger.kernel.org>, Paolo Bonzini <pbonzini@redhat.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Maxim Levitsky <mlevitsk@redhat.com>,
	Lai Jiangshan <jiangshan.ljs@antgroup.com>
Subject: Re: [PATCH 07/12] KVM: X86/MMU: Remove the useless struct mmu_page_path
Date: Thu, 21 Jul 2022 17:43:20 +0800	[thread overview]
Message-ID: <CAJhGHyB=-bGrguLKtTh+EAr5zr--H97HUgR3WP=JTovQLkoevQ@mail.gmail.com> (raw)
In-Reply-To: <YtcQ1GuTAttXaUk+@google.com>

On Wed, Jul 20, 2022 at 4:15 AM Sean Christopherson <seanjc@google.com> wrote:
>
> Nit, s/useless/now-unused, or "no longer used".  I associate "useless" in shortlogs
> as "this <xyz> is pointless and always has been pointless", whereas "now-unused"
> is likely to be interpreted as "remove <xyz> as it's no longer used after recent
> changes".
>
> Alternatively, can this patch be squashed with the patch that removes
> mmu_pages_clear_parents()?  Yeah, it'll be a (much?) larger patch, but leaving
> dead code behind is arguably worse.

Defined by the C-language and the machine, struct mmu_page_path is used
in for_each_sp() and the data is set and updated every iteration.

It is not really dead code.

Defined by the sematic that we want, gathering unsync pages,
we don't need struct mmu_page_path, since the struct is not used
by "someone reading it".

>
> On Sun, Jun 05, 2022, Lai Jiangshan wrote:
> > From: Lai Jiangshan <jiangshan.ljs@antgroup.com>
> >
> > struct mmu_page_path is set and updated but never used since
> > mmu_pages_clear_parents() is removed.
> >
> > Remove it.
> >
> > Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
> > ---

  reply	other threads:[~2022-07-21  9:43 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-05  6:43 [PATCH 00/12] KVM: X86/MMU: Simpliy mmu_unsync_walk() Lai Jiangshan
2022-06-05  6:43 ` [PATCH 01/12] KVM: X86/MMU: Warn if sp->unsync_children > 0 in link_shadow_page() Lai Jiangshan
2022-06-05  6:43 ` [PATCH 02/12] KVM: X86/MMU: Rename kvm_unlink_unsync_page() to kvm_mmu_page_clear_unsync() Lai Jiangshan
2022-07-14 22:10   ` Sean Christopherson
2022-06-05  6:43 ` [PATCH 03/12] KVM: X86/MMU: Split a part of kvm_unsync_page() as kvm_mmu_page_mark_unsync() Lai Jiangshan
2022-07-14 22:19   ` Sean Christopherson
2022-06-05  6:43 ` [PATCH 04/12] KVM: X86/MMU: Remove mmu_pages_clear_parents() Lai Jiangshan
2022-07-14 23:15   ` Sean Christopherson
2022-06-05  6:43 ` [PATCH 05/12] KVM: X86/MMU: Clear unsync bit directly in __mmu_unsync_walk() Lai Jiangshan
2022-07-19 19:52   ` Sean Christopherson
2022-07-21  9:32     ` Lai Jiangshan
2022-07-21 16:26       ` Sean Christopherson
2022-06-05  6:43 ` [PATCH 06/12] KVM: X86/MMU: Rename mmu_unsync_walk() to mmu_unsync_walk_and_clear() Lai Jiangshan
2022-07-19 20:07   ` Sean Christopherson
2022-06-05  6:43 ` [PATCH 07/12] KVM: X86/MMU: Remove the useless struct mmu_page_path Lai Jiangshan
2022-07-19 20:15   ` Sean Christopherson
2022-07-21  9:43     ` Lai Jiangshan [this message]
2022-07-21 15:25       ` Sean Christopherson
2022-06-05  6:43 ` [PATCH 08/12] KVM: X86/MMU: Remove the useless idx from struct kvm_mmu_pages Lai Jiangshan
2022-07-19 20:31   ` Sean Christopherson
2022-06-05  6:43 ` [PATCH 09/12] KVM: X86/MMU: Unfold struct mmu_page_and_offset in " Lai Jiangshan
2022-06-05  6:43 ` [PATCH 10/12] KVM: X86/MMU: Don't add parents to " Lai Jiangshan
2022-07-19 20:34   ` Sean Christopherson
2022-06-05  6:43 ` [PATCH 11/12] KVM: X86/MMU: Remove mmu_pages_first() and mmu_pages_next() Lai Jiangshan
2022-07-19 20:40   ` Sean Christopherson
2022-06-05  6:43 ` [PATCH 12/12] KVM: X86/MMU: Rename struct kvm_mmu_pages to struct kvm_mmu_page_vec Lai Jiangshan
2022-07-19 20:45   ` Sean Christopherson

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