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Date:   Tue, 3 Apr 2018 15:39:27 -0400
From:   Jerome Glisse <jglisse@redhat.com>
To:     Laurent Dufour <ldufour@linux.vnet.ibm.com>
Cc:     paulmck@linux.vnet.ibm.com, peterz@infradead.org,
        akpm@linux-foundation.org, kirill@shutemov.name,
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        benh@kernel.crashing.org, mpe@ellerman.id.au, paulus@samba.org,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, hpa@zytor.com,
        Will Deacon <will.deacon@arm.com>,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Alexei Starovoitov <alexei.starovoitov@gmail.com>,
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        Daniel Jordan <daniel.m.jordan@oracle.com>,
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        Tim Chen <tim.c.chen@linux.intel.com>,
        linuxppc-dev@lists.ozlabs.org, x86@kernel.org
Subject: Re: [PATCH v9 15/24] mm: Introduce __vm_normal_page()
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On Tue, Mar 13, 2018 at 06:59:45PM +0100, Laurent Dufour wrote:
> When dealing with the speculative fault path we should use the VMA's field
> cached value stored in the vm_fault structure.
> 
> Currently vm_normal_page() is using the pointer to the VMA to fetch the
> vm_flags value. This patch provides a new __vm_normal_page() which is
> receiving the vm_flags flags value as parameter.
> 
> Note: The speculative path is turned on for architecture providing support
> for special PTE flag. So only the first block of vm_normal_page is used
> during the speculative path.

Might be a good idea to explicitly have SPECULATIVE Kconfig option depends
on ARCH_PTE_SPECIAL and a comment for !HAVE_PTE_SPECIAL in the function
explaining that speculative page fault should never reach that point.

Cheers,
J?r?me