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Date:   Sun, 9 Sep 2018 12:07:14 -0700
From:   Matthew Wilcox <willy@infradead.org>
To:     Wang Long <wanglong19@meituan.com>
Cc:     akpm@linux-foundation.org, zwisler@kernel.org,
        linux-kernel@vger.kernel.org, jack@suse.cz, heguanjun@meituan.com
Subject: Re: [PATCH] radix-tree: optimization for radix_tree_init_maxnodes
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On Sun, Sep 09, 2018 at 09:21:00PM +0800, Wang Long wrote:
> if i == 0, height_to_maxnodes[i] = 0,
> if i >= 1, height_to_maxnodes[i] = height_to_maxnodes[i-1]
> 				+ __maxindex(i-1) + 1.
> 
> so delete height_to_maxindex and optimize the calculation of
> height_to_maxnodes array.

Thanks for your patch.  Unfortunately, this entire function is scheduled
for deletion, so I won't be applying it.

If you're interested in the radix tree, I'd recommend looking at its
replacement, the XArray.  The current version is at
http://git.infradead.org/users/willy/linux-dax.git/shortlog/refs/heads/xarray
but I'll be pushing another version out in the next few days.