Re: [PATCH v2 1/3] mm: alloc_contig_range: allow to specify GFP mask

[Vlastimil Babka <vbabka@suse.cz>]

On 01/27/2017 06:23 PM, Lucas Stach wrote:
> Currently alloc_contig_range assumes that the compaction should
> be done with the default GFP_KERNEL flags. This is probably
> right for all current uses of this interface, but may change as
> CMA is used in more use-cases (including being the default DMA
> memory allocator on some platforms).
>
> Change the function prototype, to allow for passing through the
> GFP mask set by upper layers.
>
> Also respect global restrictions by applying memalloc_noio_flags
> to the passed in flags.
>
> Signed-off-by: Lucas Stach <l.stach@pengutronix.de>
> Acked-by: Michal Hocko <mhocko@suse.com>


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

> ---
> v2: add memalloc_noio restriction
> ---
>  include/linux/gfp.h | 2 +-
>  mm/cma.c            | 3 ++-
>  mm/hugetlb.c        | 3 ++-
>  mm/page_alloc.c     | 5 +++--
>  4 files changed, 8 insertions(+), 5 deletions(-)
>
> diff --git a/include/linux/gfp.h b/include/linux/gfp.h
> index 4175dca4ac39..1efa221e0e1d 100644
> --- a/include/linux/gfp.h
> +++ b/include/linux/gfp.h
> @@ -549,7 +549,7 @@ static inline bool pm_suspended_storage(void)
>  #if (defined(CONFIG_MEMORY_ISOLATION) && defined(CONFIG_COMPACTION)) || defined(CONFIG_CMA)
>  /* The below functions must be run on a range from a single zone. */
>  extern int alloc_contig_range(unsigned long start, unsigned long end,
> -			      unsigned migratetype);
> +			      unsigned migratetype, gfp_t gfp_mask);
>  extern void free_contig_range(unsigned long pfn, unsigned nr_pages);
>  #endif
>
> diff --git a/mm/cma.c b/mm/cma.c
> index c960459eda7e..fbd67d866f67 100644
> --- a/mm/cma.c
> +++ b/mm/cma.c
> @@ -407,7 +407,8 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align)
>
>  		pfn = cma->base_pfn + (bitmap_no << cma->order_per_bit);
>  		mutex_lock(&cma_mutex);
> -		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
> +		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA,
> +					 GFP_KERNEL);
>  		mutex_unlock(&cma_mutex);
>  		if (ret == 0) {
>  			page = pfn_to_page(pfn);
> diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> index 3edb759c5c7d..6ed8b160fc0d 100644
> --- a/mm/hugetlb.c
> +++ b/mm/hugetlb.c
> @@ -1051,7 +1051,8 @@ static int __alloc_gigantic_page(unsigned long start_pfn,
>  				unsigned long nr_pages)
>  {
>  	unsigned long end_pfn = start_pfn + nr_pages;
> -	return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
> +	return alloc_contig_range(start_pfn, end_pfn, MIGRATE_MOVABLE,
> +				  GFP_KERNEL);
>  }
>
>  static bool pfn_range_valid_gigantic(struct zone *z,
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index eced9fee582b..c5a745b521c0 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -7230,6 +7230,7 @@ static int __alloc_contig_migrate_range(struct compact_control *cc,
>   *			#MIGRATE_MOVABLE or #MIGRATE_CMA).  All pageblocks
>   *			in range must have the same migratetype and it must
>   *			be either of the two.
> + * @gfp_mask:	GFP mask to use during compaction
>   *
>   * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
>   * aligned, however it's the caller's responsibility to guarantee that
> @@ -7243,7 +7244,7 @@ static int __alloc_contig_migrate_range(struct compact_control *cc,
>   * need to be freed with free_contig_range().
>   */
>  int alloc_contig_range(unsigned long start, unsigned long end,
> -		       unsigned migratetype)
> +		       unsigned migratetype, gfp_t gfp_mask)
>  {
>  	unsigned long outer_start, outer_end;
>  	unsigned int order;
> @@ -7255,7 +7256,7 @@ int alloc_contig_range(unsigned long start, unsigned long end,
>  		.zone = page_zone(pfn_to_page(start)),
>  		.mode = MIGRATE_SYNC,
>  		.ignore_skip_hint = true,
> -		.gfp_mask = GFP_KERNEL,
> +		.gfp_mask = memalloc_noio_flags(gfp_mask),
>  	};
>  	INIT_LIST_HEAD(&cc.migratepages);
>
>

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