Re: [PATCH v6 6/6] mm/page_isolation: remove migratetype parameter from more functions.

[Vlastimil Babka <vbabka@suse.cz>]

On 5/30/25 18:22, Zi Yan wrote:
> migratetype is no longer overwritten during pageblock isolation,
> start_isolate_page_range(), has_unmovable_pages(), and
> set_migratetype_isolate() no longer need which migratetype to restore
> during isolation failure.
> 
> For has_unmoable_pages(), it needs to know if the isolation is for CMA
> allocation, so adding CMA_ALLOCATION to provide the information. At the
> same time change isolation flags to enum pb_isolate_mode
> (PB_ISOLATE_MODE_MEM_OFFLINE, PB_ISOLATE_MODE_CMA_ALLOC,
> PB_ISOLATE_MODE_OTHER). Remove REPORT_FAILURE and check
> MEMORY_OFFLINE instead, since only PB_ISOLATE_MODE_MEM_OFFLINE reports
> isolation failures.
> 
> alloc_contig_range() no longer needs migratetype. Replace it with
> enum acr_flags_t to tell if an allocation is for CMA. So does
> __alloc_contig_migrate_range().
> 
> Signed-off-by: Zi Yan <ziy@nvidia.com>

Reviewed-by: Vlastimil Babka <vbabka@suse.cz>

> ---
>  drivers/virtio/virtio_mem.c    |  2 +-
>  include/linux/gfp.h            |  9 ++++-
>  include/linux/page-isolation.h | 20 ++++++++--
>  include/trace/events/kmem.h    | 14 ++++---
>  mm/cma.c                       |  2 +-
>  mm/memory_hotplug.c            |  6 +--
>  mm/page_alloc.c                | 27 ++++++-------
>  mm/page_isolation.c            | 70 +++++++++++++++-------------------
>  8 files changed, 82 insertions(+), 68 deletions(-)
> 
> diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c
> index 56d0dbe62163..6bce70b139b2 100644
> --- a/drivers/virtio/virtio_mem.c
> +++ b/drivers/virtio/virtio_mem.c
> @@ -1243,7 +1243,7 @@ static int virtio_mem_fake_offline(struct virtio_mem *vm, unsigned long pfn,
>  		if (atomic_read(&vm->config_changed))
>  			return -EAGAIN;
>  
> -		rc = alloc_contig_range(pfn, pfn + nr_pages, MIGRATE_MOVABLE,
> +		rc = alloc_contig_range(pfn, pfn + nr_pages, ACR_OTHER,
>  					GFP_KERNEL);
>  		if (rc == -ENOMEM)
>  			/* whoops, out of memory */
> diff --git a/include/linux/gfp.h b/include/linux/gfp.h
> index be160e8d8bcb..51990d571e3e 100644
> --- a/include/linux/gfp.h
> +++ b/include/linux/gfp.h
> @@ -423,9 +423,16 @@ static inline bool gfp_compaction_allowed(gfp_t gfp_mask)
>  extern gfp_t vma_thp_gfp_mask(struct vm_area_struct *vma);
>  
>  #ifdef CONFIG_CONTIG_ALLOC
> +
> +enum acr_flags_t {
> +	ACR_CMA,	// CMA allocation
> +	ACR_OTHER,	// other allocation
> +};
> +
>  /* The below functions must be run on a range from a single zone. */
>  extern int alloc_contig_range_noprof(unsigned long start, unsigned long end,
> -			      unsigned migratetype, gfp_t gfp_mask);
> +				     enum acr_flags_t alloc_flags,
> +				     gfp_t gfp_mask);

Nit: when used this way I think it's also rather a "mode" than "flags". It's
probably sufficient though, I don't expect we'll be adding more and want to
combine them in a flags way. So it's just about the enum's name.

>  #define alloc_contig_range(...)			alloc_hooks(alloc_contig_range_noprof(__VA_ARGS__))
>