Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH v8 2/9] mmap: make mlock_future_check() global
To:     Mike Rapoport <rppt@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Andy Lutomirski <luto@kernel.org>,
        Arnd Bergmann <arnd@arndb.de>, Borislav Petkov <bp@alien8.de>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Christopher Lameter <cl@linux.com>,
        Dan Williams <dan.j.williams@intel.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Elena Reshetova <elena.reshetova@intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
        James Bottomley <jejb@linux.ibm.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Matthew Wilcox <willy@infradead.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Rick Edgecombe <rick.p.edgecombe@intel.com>,
        Shuah Khan <shuah@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Tycho Andersen <tycho@tycho.ws>, Will Deacon <will@kernel.org>,
        linux-api@vger.kernel.org, linux-arch@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org,
        linux-fsdevel@vger.kernel.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
        linux-nvdimm@lists.01.org, linux-riscv@lists.infradead.org,
        x86@kernel.org
References: <20201110151444.20662-1-rppt@kernel.org>
 <20201110151444.20662-3-rppt@kernel.org>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat GmbH
Message-ID: <9e2fafd7-abb0-aa79-fa66-cd8662307446@redhat.com>
Date:   Tue, 10 Nov 2020 18:17:26 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101
 Thunderbird/68.6.0
MIME-Version: 1.0
In-Reply-To: <20201110151444.20662-3-rppt@kernel.org>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk

On 10.11.20 16:14, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
> 
> It will be used by the upcoming secret memory implementation.
> 
> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
> ---
>   mm/internal.h | 3 +++
>   mm/mmap.c     | 5 ++---
>   2 files changed, 5 insertions(+), 3 deletions(-)
> 
> diff --git a/mm/internal.h b/mm/internal.h
> index c43ccdddb0f6..ae146a260b14 100644
> --- a/mm/internal.h
> +++ b/mm/internal.h
> @@ -348,6 +348,9 @@ static inline void munlock_vma_pages_all(struct vm_area_struct *vma)
>   extern void mlock_vma_page(struct page *page);
>   extern unsigned int munlock_vma_page(struct page *page);
>   
> +extern int mlock_future_check(struct mm_struct *mm, unsigned long flags,
> +			      unsigned long len);
> +
>   /*
>    * Clear the page's PageMlocked().  This can be useful in a situation where
>    * we want to unconditionally remove a page from the pagecache -- e.g.,
> diff --git a/mm/mmap.c b/mm/mmap.c
> index 61f72b09d990..c481f088bd50 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -1348,9 +1348,8 @@ static inline unsigned long round_hint_to_min(unsigned long hint)
>   	return hint;
>   }
>   
> -static inline int mlock_future_check(struct mm_struct *mm,
> -				     unsigned long flags,
> -				     unsigned long len)
> +int mlock_future_check(struct mm_struct *mm, unsigned long flags,
> +		       unsigned long len)
>   {
>   	unsigned long locked, lock_limit;
>   
> 

So, an interesting question is if you actually want to charge secretmem 
pages against mlock now, or if you want a dedicated secretmem cgroup 
controller instead?

-- 
Thanks,

David / dhildenb