Re: [PATCH v4 1/2] of: cache phandle nodes to reduce cost of of_find_node_by_phandle()

From: Andy Shevchenko
Date: Wed Feb 28 2018 - 15:19:17 EST


On Wed, Feb 28, 2018 at 9:44 PM, Frank Rowand <frowand.list@xxxxxxxxx> wrote:
> On 02/28/18 11:31, Andy Shevchenko wrote:
>> On Wed, Feb 28, 2018 at 9:04 PM, <frowand.list@xxxxxxxxx> wrote:

>> The question is why O(1) is so important? O(log(n)) wouldn't work?
>
> O(1) is not critical. It was just a nice side result.
>
>
>> Using radix_tree() I suppose allows to dynamically extend or shrink
>> the cache which would work with DT overlays.
>
> The memory usage of the phandle cache in this patch is fairly small.
> The memory overhead of a radix_tree() would not be justified.

OTOH the advantage I mentioned isn't a good argument?

--
With Best Regards,
Andy Shevchenko