Subject: Re: [PATCH net-next v4 3/9] dpll: core: Add DPLL framework base functions

From: Vadim Fedorenko <[email-masked]>
Date: Tue, 15 Aug 2023 19:38:41 +0100

On 15/08/2023 19:28, Jakub Kicinski wrote:
> On Tue, 15 Aug 2023 19:20:31 +0100 Vadim Fedorenko wrote:
>>>> +	ret = xa_alloc(&dpll_device_xa, &dpll->id, dpll, xa_limit_16b,
>>>> +		       GFP_KERNEL);
>>>
>>> Why only 16b and why not _cyclic?
>>
>> I cannot image systems with more than 65k of DPLL devices. We don't
>> store any id's of last used DPLL device, so there is no easy way to
>> restart the search from the last point. And it's not a hot path to
>> optimize it.
> 
> I think this gets used under the xa_lock() so you can just add a static
> variable inside the function to remember previous allocation.
> 
> I don't expect >64k devices either, obviously, but what are we saving
> by not allowing the full u32 range?

I don't see any benefits for either _cyclic or u32 range, but if you 
insist I can change it.