Re: zone movable patches comments

[KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>]

On Tue, 10 Jul 2007 10:48:04 +0100
Andy Whitcroft <apw@shadowen.org> wrote:


> I would have expected all of the is_zonename() checks to include the
> zone_is_configured() checks, to allow the optimiser to catch on and
> elide the code.
> 
>     if (zone_is_configured(ZONE_DMA32)
> 	return zone == zone->zone_pgdat->node_zones + ZONE_DMA32;
>     else
> 	return 0;
> 
> Perhaps a little helper:
> 
> static inline zone_idx_is(int idx, int target)
> {
> 	if (zone_is_configured(target))
> 		return idx == target;
> 	else
> 		return 0;
> }
> 
Ah, this looks nice. 


> You are able to always assign these as the array is sized on
> MAX_POSSIBLE_ZONES, so I would have thought that these could be
> statically initialised right?
> 
> static char * const zone_names = {
> [ZONE_DMA] = "DMA",
> [ZONE_DMA32] = "DMA32",
> ...
> };
> 
> 
> And in fact if you were to simply size sysctl_lowmem_reserve_ratio at
> MAX_POSSIBLE_ZONES could you not do the same there too?  Then you would
> not need to introduce zone_variables_init().
> 
> int sysctl_lowmem_reserve_ratio[MAX_POSSIBLE_ZONES] = {
> [ZONE_DMA] = 256,
> [ZONE_DMA32] = 256,
> [ZONE_HIGHMEM] = 32
> };
> 
Oh, it's simpler. thank you.

-Kame

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