Re: [PATCH v3 4/4] mm/page_isolation: remove migratetype parameter from more functions.

[Johannes Weiner <hannes@cmpxchg.org>]

On Wed, May 07, 2025 at 05:10:59PM -0400, Zi Yan wrote:
> @@ -22,8 +22,17 @@ static inline bool is_migrate_isolate(int migratetype)
>  }
>  #endif
>  
> -#define MEMORY_OFFLINE	0x1
> -#define REPORT_FAILURE	0x2
> +/*
> + * Isolation flags:
> + * MEMORY_OFFLINE - isolate to offline (!allocate) memory e.g., skip over
> + *		    PageHWPoison() pages and PageOffline() pages.
> + * REPORT_FAILURE - report details about the failure to isolate the range
> + * CMA_ALLOCATION - isolate for CMA allocations
> + */
> +typedef unsigned int __bitwise isol_flags_t;
> +#define MEMORY_OFFLINE		((__force isol_flags_t)BIT(0))
> +#define REPORT_FAILURE		((__force isol_flags_t)BIT(1))
> +#define CMA_ALLOCATION		((__force isol_flags_t)BIT(2))

Should this be a mode enum instead? MEMORY_OFFLINE and CMA_ALLOCATION
are exclusive modes AFAICS. REPORT_FAILURE is a flag, but it's only
used by MEMORY_OFFLINE, so probably better to make it a part of that
instead of having both a mode and a flag field.