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;
Date:   Wed, 21 Aug 2019 09:22:44 +0800
From:   Wei Yang <richardw.yang@linux.intel.com>
To:     Matthew Wilcox <willy@infradead.org>
Cc:     Wei Yang <richardw.yang@linux.intel.com>,
        Vlastimil Babka <vbabka@suse.cz>,
        Christoph Hellwig <hch@infradead.org>,
        akpm@linux-foundation.org, mgorman@techsingularity.net,
        osalvador@suse.de, linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/3] mm/mmap.c: extract __vma_unlink_list as counter part
 for __vma_link_list
Message-ID: <20190821012244.GA13653@richard>
Reply-To: Wei Yang <richardw.yang@linux.intel.com>
References: <20190814021755.1977-1-richardw.yang@linux.intel.com>
 <20190814021755.1977-3-richardw.yang@linux.intel.com>
 <20190814051611.GA1958@infradead.org>
 <20190814065703.GA6433@richard>
 <2c5cdffd-f405-23b8-98f5-37b95ca9b027@suse.cz>
 <20190820172629.GB4949@bombadil.infradead.org>
 <20190821005234.GA5540@richard>
 <20190821005417.GC18776@bombadil.infradead.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20190821005417.GC18776@bombadil.infradead.org>
User-Agent: Mutt/1.9.4 (2018-02-28)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Tue, Aug 20, 2019 at 05:54:17PM -0700, Matthew Wilcox wrote:
>On Wed, Aug 21, 2019 at 08:52:34AM +0800, Wei Yang wrote:
>> On Tue, Aug 20, 2019 at 10:26:29AM -0700, Matthew Wilcox wrote:
>> >On Wed, Aug 14, 2019 at 11:19:37AM +0200, Vlastimil Babka wrote:
>> >> 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 :)
>> >
>> >I'm working to get rid of vm_prev and vm_next, so it would probably be
>> >wasted effort.
>> 
>> You mean replace it with list_head?
>
>No, replace the rbtree with a new tree.  https://lwn.net/Articles/787629/

Sounds interesting.

While I am not sure the plan is settled down, and how long it would take to
replace the rb_tree with maple tree. I guess it would probably take some time
to get merged upstream.

IMHO, it would be good to have this cleanup in current kernel. Do you agree?

-- 
Wei Yang
Help you, Help me