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Date:   Tue, 15 Aug 2023 19:38:41 +0100
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Subject: Re: [PATCH net-next v4 3/9] dpll: core: Add DPLL framework base
 functions
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To:     Jakub Kicinski <kuba@kernel.org>
Cc:     Jiri Pirko <jiri@resnulli.us>,
        Arkadiusz Kubalewski <arkadiusz.kubalewski@intel.com>,
        Jonathan Lemon <jonathan.lemon@gmail.com>,
        Paolo Abeni <pabeni@redhat.com>,
        Milena Olech <milena.olech@intel.com>,
        Michal Michalik <michal.michalik@intel.com>,
        linux-arm-kernel@lists.infradead.org, poros@redhat.com,
        mschmidt@redhat.com, netdev@vger.kernel.org,
        linux-clk@vger.kernel.org, Bart Van Assche <bvanassche@acm.org>,
        intel-wired-lan@lists.osuosl.org, Jiri Pirko <jiri@nvidia.com>
References: <20230811200340.577359-1-vadim.fedorenko@linux.dev>
 <20230811200340.577359-4-vadim.fedorenko@linux.dev>
 <20230814201709.655a24e2@kernel.org>
 <ef2eca98-4fcc-b448-fecb-38695238f87b@linux.dev>
 <20230815112856.1f1bd3ac@kernel.org>
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From:   Vadim Fedorenko <vadim.fedorenko@linux.dev>
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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.