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From:   Kees Cook <keescook@chromium.org>
Date:   Fri, 2 Feb 2018 08:11:15 +1100
Message-ID: <CAGXu5jKKeJL13dcaY=fDJ8AiOXDP5MhQTqDYDOt3a374CFA1HQ@mail.gmail.com>
Subject: Re: [PATCH 3/6] struct page: add field for vm_struct
To:     Igor Stoppa <igor.stoppa@huawei.com>
Cc:     Christopher Lameter <cl@linux.com>, jglisse@redhat.com,
        Michal Hocko <mhocko@kernel.org>,
        Laura Abbott <labbott@redhat.com>,
        Christoph Hellwig <hch@infradead.org>,
        Matthew Wilcox <willy@infradead.org>,
        linux-security-module <linux-security-module@vger.kernel.org>,
        Linux-MM <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        kernel-hardening@lists.openwall.com
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On Thu, Feb 1, 2018 at 11:42 PM, Igor Stoppa <igor.stoppa@huawei.com> wrote:
> On 01/02/18 02:00, Christopher Lameter wrote:
>> Would it not be better to use compound page allocations here?
>> page_head(whatever) gets you the head page where you can store all sorts
>> of information about the chunk of memory.
>
> Can you please point me to this function/macro? I don't seem to be able
> to find it, at least not in 4.15

IIUC, he means PageHead(), which is also hard to grep for, since it is
a constructed name, via Page##uname in include/linux/page-flags.h:

__PAGEFLAG(Head, head, PF_ANY) CLEARPAGEFLAG(Head, head, PF_ANY)

-Kees

-- 
Kees Cook
Pixel Security