Re: [patch 04/10] slab: cache_estimate cleanup

[Andrew Morton <akpm@osdl.org>]

"Pekka Enberg" <penberg@cs.helsinki.fi> wrote:
>
> From: Steven Rostedt <rostedt@goodmis.org>
> 
> This patch cleans up cache_estimate() in mm/slab.c and improves the
> algorithm from O(n) to O(1). We first calculate the maximum number of
> objects a slab can hold after struct slab and kmem_bufctl_t for each
> object has been given enough space. After that, to respect alignment
> rules, we decrease the number of objects if necessary. As required
> padding is at most align-1 and memory of obj_size is at least align,
> it is always enough to decrease number of objects by one.
> 
> The optimization was originally made by Balbir Singh with more 
> improvements from Steven Rostedt. Manfred Spraul provider further
> modifications: no loop at all for the off-slab case and added comments
> to explain the background.
> 
> ...
> -	size_t wastage = PAGE_SIZE << gfporder;
> -	size_t extra = 0;
> -	size_t base = 0;
> ...
> +	size_t mgmt_size;
> +	size_t slab_size = PAGE_SIZE << gfporder;

Can anyone think of a reason for using size_t in there instead of plain old
unsigned int?