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Subject: Re: [PATCH v3 10/11] null_blk: allow non power of 2 zoned devices
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To:     Pankaj Raghav <p.raghav@samsung.com>,
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From:   Bart Van Assche <bvanassche@acm.org>
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On 5/9/22 04:56, Pankaj Raghav wrote:
> Even though I am not sure if this optimization will directly add value
> looking at my experiments with the current change, I can fold this in
> with a comment on top of zone_size_sect_shifts variable stating that
> size can be npo2 and this variable is only meaningful for the po2 size
> scenario.

Have these experiments perhaps been run on an x86_64 CPU? These CPUs 
only need a single instruction to calculate ilog2(). No equivalent of 
that instruction is available on ARM CPUs as far as I know. I think the 
optimization Damien proposed will help on ARM CPUs.

Thanks,

Bart.