Re: [PATCH] zone gfp_flags generate from ZONE_ constants

Andrew Morton
2006-01-17T21:22:14Z

Andy Whitcroft <apw@shadowen.org> wrote:
>
> +/*
> + * Generate the zone modifier bit. Zone ZONE_DEFAULT doesn't require a bit
> + * as the absence of all zone modifiers implies this zone. Renormalise the
> + * zone number such that ZONE_DEFAULT is at the bottom and discard it.
> + * These must fit within the bitmask GFP_ZONEMASK defined in linux/mmzone.h.
> + */
> +#define __ZONE_BIT(x) (((x) ^ ZONE_DEFAULT) - 1)
> +#define ZONE_MODIFIER(x) ((__force gfp_t)(((x) == ZONE_DEFAULT)? (0) : \
> + 1UL << __ZONE_BIT(x)))
> +
> +#define __GFP_DMA ZONE_MODIFIER(ZONE_DMA)
> +#define __GFP_HIGHMEM ZONE_MODIFIER(ZONE_HIGHMEM)
> #ifdef CONFIG_DMA_IS_DMA32
> -#define __GFP_DMA32 ((__force gfp_t)0x01) /* ZONE_DMA is ZONE_DMA32 */
> +#define __GFP_DMA32 ZONE_MODIFIER(ZONE_DMA) /* ZONE_DMA is ZONE_DMA32 */
> #elif BITS_PER_LONG < 64
> -#define __GFP_DMA32 ((__force gfp_t)0x00) /* ZONE_NORMAL is ZONE_DMA32 */
> +#define __GFP_DMA32 ZONE_MODIFIER(ZONE_NORMAL) /* ZONE_NORMAL is ZONE_DMA32 */
> #else
> -#define __GFP_DMA32 ((__force gfp_t)0x04) /* Has own ZONE_DMA32 */
> +#define __GFP_DMA32 ZONE_MODIFIER(ZONE_DMA32) /* Has own ZONE_DMA32 */
> #endif

eek. We often look at the hex value of gfp flags in debug output to work
out what sort of allocation is being attempted.

I guess we could print out the values of these things at boot time..

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: email@kvack.org