linux-kernel - Re: [PATCH 17/31] kvm: teach kvm to map page teams as huge pages.

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Date:	Wed, 6 Apr 2016 01:37:30 +0200
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	Hugh Dickins <hughd@...gle.com>,
	Andrew Morton <akpm@...ux-foundation.org>
Cc:	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
	Andrea Arcangeli <aarcange@...hat.com>,
	Andres Lagar-Cavilla <andreslc@...gle.com>,
	Yang Shi <yang.shi@...aro.org>, Ning Qu <quning@...il.com>,
	linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
	linux-mm@...ck.org
Subject: Re: [PATCH 17/31] kvm: teach kvm to map page teams as huge pages.



On 05/04/2016 23:41, Hugh Dickins wrote:
> +/*
> + * We are holding kvm->mmu_lock, serializing against mmu notifiers.
> + * We have a ref on page.
> ...
> +static bool is_huge_tmpfs(struct kvm_vcpu *vcpu,
> +			  unsigned long address, struct page *page)

vcpu is only used to access vcpu->kvm->mm.  If it's still possible to
give a sensible rule for locking, I wouldn't mind if is_huge_tmpfs took
the mm directly and was moved out of KVM.  Otherwise, it would be quite
easy for people touch mm code to miss it.

Apart from this, both patches look good.

Paolo