Re: [Xen-devel] [PATCH v2 05/18] mini-os: add nr_free_pages counter

[Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>]

Juergen Gross, on Fri 05 Aug 2016 19:35:49 +0200, wrote:
> Add a variable holding the number of available memory pages. This will
> aid auto-ballooning later.
> 
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
> Reviewed-by: Wei Liu <wei.liu2@xxxxxxxxxx>

Acked-by: Samuel Thibault <samuel.thibault@xxxxxxxxxxxx>

> ---
>  include/mm.h | 1 +
>  mm.c         | 6 ++++++
>  2 files changed, 7 insertions(+)
> 
> diff --git a/include/mm.h b/include/mm.h
> index a48f485..b97b43e 100644
> --- a/include/mm.h
> +++ b/include/mm.h
> @@ -42,6 +42,7 @@
>  #define STACK_SIZE_PAGE_ORDER __STACK_SIZE_PAGE_ORDER
>  #define STACK_SIZE __STACK_SIZE
>  
> +extern unsigned long nr_free_pages;
>  
>  void init_mm(void);
>  unsigned long alloc_pages(int order);
> diff --git a/mm.c b/mm.c
> index 0dd4862..263a356 100644
> --- a/mm.c
> +++ b/mm.c
> @@ -53,6 +53,8 @@ static unsigned long *alloc_bitmap;
>  #define allocated_in_map(_pn) \
>  (alloc_bitmap[(_pn)/PAGES_PER_MAPWORD] & 
> (1UL<<((_pn)&(PAGES_PER_MAPWORD-1))))
>  
> +unsigned long nr_free_pages;
> +
>  /*
>   * Hint regarding bitwise arithmetic in map_{alloc,free}:
>   *  -(1<<n)  sets all bits >= n. 
> @@ -81,6 +83,8 @@ static void map_alloc(unsigned long first_page, unsigned 
> long nr_pages)
>          while ( ++curr_idx < end_idx ) alloc_bitmap[curr_idx] = ~0UL;
>          alloc_bitmap[curr_idx] |= (1UL<<end_off)-1;
>      }
> +
> +    nr_free_pages -= nr_pages;
>  }
>  
>  
> @@ -93,6 +97,8 @@ static void map_free(unsigned long first_page, unsigned 
> long nr_pages)
>      end_idx   = (first_page + nr_pages) / PAGES_PER_MAPWORD;
>      end_off   = (first_page + nr_pages) & (PAGES_PER_MAPWORD-1);
>  
> +    nr_free_pages += nr_pages;
> +
>      if ( curr_idx == end_idx )
>      {
>          alloc_bitmap[curr_idx] &= -(1UL<<end_off) | ((1UL<<start_off)-1);
> -- 
> 2.6.6
> 

-- 
Samuel
In mutt, type cthis
Dans mutt, taper cceci

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