Re: [PATCH] mm: page_isolation: write proper kerneldoc

[Mike Rapoport <rppt@kernel.org>]

On Fri, May 19, 2023 at 01:16:52PM +0200, Johannes Weiner wrote:
> And remove the incorrect header comments.
> 
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
> ---
>  include/linux/page-isolation.h | 24 ++++++------------------
>  mm/page_isolation.c            | 29 ++++++++++++++++++++++++-----
>  2 files changed, 30 insertions(+), 23 deletions(-)
> 
> diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h
> index 5456b7be38ae..0ab089e89db4 100644
> --- a/include/linux/page-isolation.h
> +++ b/include/linux/page-isolation.h
> @@ -37,24 +37,12 @@ void set_pageblock_migratetype(struct page *page, int migratetype);
>  int move_freepages_block(struct zone *zone, struct page *page,
>  				int migratetype, int *num_movable);
>  
> -/*
> - * Changes migrate type in [start_pfn, end_pfn) to be MIGRATE_ISOLATE.
> - */
> -int
> -start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
> -			 int migratetype, int flags, gfp_t gfp_flags);
> -
> -/*
> - * Changes MIGRATE_ISOLATE to MIGRATE_MOVABLE.
> - * target range is [start_pfn, end_pfn)
> - */
> -void
> -undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
> -			int migratetype);
> -
> -/*
> - * Test all pages in [start_pfn, end_pfn) are isolated or not.
> - */
> +int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
> +			     int migratetype, int flags, gfp_t gfp_flags);
> +
> +void undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
> +			     int migratetype);
> +
>  int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
>  			int isol_flags);
>  
> diff --git a/mm/page_isolation.c b/mm/page_isolation.c
> index c6f3605e37ab..e7d7685104de 100644
> --- a/mm/page_isolation.c
> +++ b/mm/page_isolation.c
> @@ -481,8 +481,7 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
>  }
>  
>  /**
> - * start_isolate_page_range() - make page-allocation-type of range of pages to
> - * be MIGRATE_ISOLATE.
> + * start_isolate_page_range() - mark page range MIGRATE_ISOLATE
>   * @start_pfn:		The lower PFN of the range to be isolated.
>   * @end_pfn:		The upper PFN of the range to be isolated.

I don't remember seeing lower and upper to describe memory ranges in our
docs. Do you mind changing these to first/last?

>   * @migratetype:	Migrate type to set in error recovery.
> @@ -571,8 +570,14 @@ int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
>  	return 0;
>  }
>  
> -/*
> - * Make isolated pages available again.
> +/**
> + * undo_isolate_page_range - undo effects of start_isolate_page_range()
> + * @start_pfn:		The lower PFN of the isolated range
> + * @end_pfn:		The upper PFN of the isolated range

Here as well

> + * @migratetype:	New migrate type to set on the range
> + *
> + * This finds every MIGRATE_ISOLATE page block in the given range
> + * and switches it to @migratetype.
>   */
>  void undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
>  			    int migratetype)
> @@ -631,7 +636,21 @@ __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn,
>  	return pfn;
>  }
>  
> -/* Caller should ensure that requested range is in a single zone */
> +/**
> + * test_pages_isolated - check if pageblocks in range are isolated
> + * @start_pfn:		The first PFN of the isolated range
> + * @end_pfn:		The first PFN *after* the isolated range
> + * @isol_flags:		Testing mode flags
> + *
> + * This tests if all in the specified range are free.
> + *
> + * If %MEMORY_OFFLINE is specified in @flags, it will consider
> + * poisoned and offlined pages free as well.
> + *
> + * Caller must ensure the requested range doesn't span zones.
> + *
> + * Returns 0 if true, -EBUSY if one or more pages are in use.
> + */
>  int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn,
>  			int isol_flags)
>  {
> -- 
> 2.40.0
> 
> 

-- 
Sincerely yours,
Mike.