Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Subject: Re: [PATCH 3/3] mm/mmap.c: extract __vma_unlink_list as counter part
 for __vma_link_list
To:     Wei Yang <richardw.yang@linux.intel.com>,
        Christoph Hellwig <hch@infradead.org>
Cc:     akpm@linux-foundation.org, mgorman@techsingularity.net,
        osalvador@suse.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org
References: <20190814021755.1977-1-richardw.yang@linux.intel.com>
 <20190814021755.1977-3-richardw.yang@linux.intel.com>
 <20190814051611.GA1958@infradead.org> <20190814065703.GA6433@richard>
From:   Vlastimil Babka <vbabka@suse.cz>
Message-ID: <2c5cdffd-f405-23b8-98f5-37b95ca9b027@suse.cz>
Date:   Wed, 14 Aug 2019 11:19:37 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.8.0
MIME-Version: 1.0
In-Reply-To: <20190814065703.GA6433@richard>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 8/14/19 8:57 AM, Wei Yang wrote:
> On Tue, Aug 13, 2019 at 10:16:11PM -0700, Christoph Hellwig wrote:
>>Btw, is there any good reason we don't use a list_head for vma linkage?
> 
> Not sure, maybe there is some historical reason?

Seems it was single-linked until 2010 commit 297c5eee3724 ("mm: make the vma
list be doubly linked") and I guess it was just simpler to add the vm_prev link.

Conversion to list_head might be an interesting project for some "advanced
beginner" in the kernel :)