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Date:   Wed, 13 Mar 2019 14:06:03 -0700
From:   Davidlohr Bueso <dave@stgolabs.net>
To:     Laurent Dufour <ldufour@linux.ibm.com>
Cc:     lsf-pc@lists.linux-foundation.org, Linux-MM <linux-mm@kvack.org>,
        linux-kernel@vger.kernel.org, Matthew Wilcox <willy@infradead.org>
Subject: Re: [LSF/MM TOPIC] Using XArray to manage the VMA
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On Wed, 13 Mar 2019, Laurent Dufour wrote:

>If this is not too late and if there is still place available, I would 
>like to attend the MM track and propose a topic about using the XArray 
>to replace the VMA's RB tree and list.
>
>Using the XArray in place of the VMA's tree and list seems to be a 
>first step to the long way of removing/replacing the mmap_sem.

So threaded (not as in threads of execution) rbtrees are another
alternative to deal with the two data structure approach we currently
have. Having O(1) rb_prev/next() calls allows us to basically get rid of
the vma list at the cost of an extra check for each node we visit on
the way down when inserting.

Thanks,
Davidlohr