Re: [PATCH] nvmet: Reorder fields in 'struct nvmet_ns'

[Jens Axboe <axboe@kernel.dk>]

On 4/27/23 1:47 PM, Christophe JAILLET wrote:
> Group some variables based on their sizes to reduce holes.
> On x86_64, this shrinks the size of 'struct nvmet_ns' from 520 to 512
> bytes.
> 
> When such a structure is allocated in nvmet_ns_alloc(), because of the way
> memory allocation works, when 520 bytes were requested, 1024 bytes were
> allocated.
> 
> So, on x86_64, this change saves 512 bytes per allocation.
> 
> Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
> ---
> More aggressive grouping could be done to be more future proof, but the
> way the struct nvmet_ns is written suggest that some fields should be
> kept together. So keep grouping as-is.

I think you did the right thing, that move doesn't matter and it brings
it to pow-of-2 or less and that is really what matters. So looks fine to
me:

Reviewed-by: Jens Axboe <axboe@kernel.dk>

-- 
Jens Axboe