Re: [RFC v2 02/10] vfs: add support for updating access frequency

From: Zhi Yong Wu
Date: Wed Sep 26 2012 - 22:30:04 EST


On Thu, Sep 27, 2012 at 10:19 AM, Dave Chinner <david@xxxxxxxxxxxxx> wrote:
> On Wed, Sep 26, 2012 at 10:53:07AM +0800, Zhi Yong Wu wrote:
>> On Tue, Sep 25, 2012 at 5:17 PM, Dave Chinner <david@xxxxxxxxxxxxx> wrote:
>> > On Sun, Sep 23, 2012 at 08:56:27PM +0800, zwu.kernel@xxxxxxxxx wrote:
>> > I note that the code will always insert range items of a length
>> > RANGE_SIZE. This means you have a fixed object granularity and hence
>> > you have no need for a range based search. That is, you could use a
>> > radix tree where each entry in the radix tree points directly to the
>> > range object similar to how the page cache uses a radix tree for
>> > indexing pages. That brings the possibility of lockless range item
>> > lookups....
>> Great suggestion, but can we temporarily put it in TODO list? because
>> it will bring one big code change.
>
> Sure. I just wanted to point out that there are better choices for
> indexing fixed size elements than rb-trees and why it might make
> sense to use a different type of tree.
Got it, thanks. Moreover, it should also be better to use radix tree
to hold hot_inode, not only hot_range.

>
> Cheers,
>
> Dave.
> --
> Dave Chinner
> david@xxxxxxxxxxxxx



--
Regards,

Zhi Yong Wu
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