Re: pool: removing ioff?

[Jason Thorpe <thorpej%me.com@localhost>]

No objection from me.

> On Mar 16, 2019, at 12:27 AM, Maxime Villard <max%m00nbsd.net@localhost> wrote:
> 
> I would like to remove the 'ioff' argument from pool_init() and friends,
> documented as 'align_offset' in the man page. This parameter allows the
> caller to specify that the alignment given in 'align' is to be applied at
> the offset 'ioff' within the buffer.
> 
> The two users I could find are:
> 
> * sys/arch/arm/xscale/iopaau.c: iopaau_desc_4_cache and iopaau_desc_8_cache.
> 
> * sys/arch/arm/arm32/pmap.c: pmap_l2ptp_cache, at a time, and it was actually
>   a bug, the arguments were inverted...
> 
> I think we're better-off with hard-aligned structures, ie with __aligned(32)
> in the case of XSCALE. Then we just pass align=32 in the pool, and that's it.
> 
> I would prefer to avoid any confusion in the pool initializers and drop ioff,
> rather than having this kind of marginal and not-well-defined features that
> add complexity with no real good reason.
> 
> Note also that, as far as I can tell, our policy in the kernel has always
> been to hard-align the structures, and then pass the same alignment in the
> allocators.

-- thorpej