Re: [PATCH v2 18/24] page_pool: Convert frag_page to frag_nmem

[Ilias Apalodimas <ilias.apalodimas@linaro.org>]

On Thu, Jan 05, 2023 at 09:46:25PM +0000, Matthew Wilcox (Oracle) wrote:
> Remove page_pool_defrag_page() and page_pool_return_page() as they have
> no more callers.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
> ---
>  include/net/page_pool.h | 17 ++++++---------
>  net/core/page_pool.c    | 47 ++++++++++++++++++-----------------------
>  2 files changed, 26 insertions(+), 38 deletions(-)
>
> diff --git a/include/net/page_pool.h b/include/net/page_pool.h
> index 126c04315929..a9dae4b5f2f7 100644
> --- a/include/net/page_pool.h
> +++ b/include/net/page_pool.h
> @@ -262,7 +262,7 @@ struct page_pool {
>
>  	u32 pages_state_hold_cnt;
>  	unsigned int frag_offset;
> -	struct page *frag_page;
> +	struct netmem *frag_nmem;
>  	long frag_users;
>
>  #ifdef CONFIG_PAGE_POOL_STATS
> @@ -334,8 +334,8 @@ static inline struct page *page_pool_dev_alloc_pages(struct page_pool *pool)
>  	return page_pool_alloc_pages(pool, gfp);
>  }
>
> -struct page *page_pool_alloc_frag(struct page_pool *pool, unsigned int *offset,
> -				  unsigned int size, gfp_t gfp);
> +struct netmem *page_pool_alloc_frag(struct page_pool *pool,
> +		unsigned int *offset, unsigned int size, gfp_t gfp);
>
>  static inline struct page *page_pool_dev_alloc_frag(struct page_pool *pool,
>  						    unsigned int *offset,
> @@ -343,7 +343,7 @@ static inline struct page *page_pool_dev_alloc_frag(struct page_pool *pool,
>  {
>  	gfp_t gfp = (GFP_ATOMIC | __GFP_NOWARN);
>
> -	return page_pool_alloc_frag(pool, offset, size, gfp);
> +	return netmem_page(page_pool_alloc_frag(pool, offset, size, gfp));
>  }
>
>  /* get the stored dma direction. A driver might decide to treat this locally and
> @@ -399,9 +399,9 @@ void page_pool_put_defragged_netmem(struct page_pool *pool, struct netmem *nmem,
>  				  unsigned int dma_sync_size,
>  				  bool allow_direct);
>
> -static inline void page_pool_fragment_page(struct page *page, long nr)
> +static inline void page_pool_fragment_netmem(struct netmem *nmem, long nr)
>  {
> -	atomic_long_set(&page->pp_frag_count, nr);
> +	atomic_long_set(&nmem->pp_frag_count, nr);
>  }
>
>  static inline long page_pool_defrag_netmem(struct netmem *nmem, long nr)
> @@ -425,11 +425,6 @@ static inline long page_pool_defrag_netmem(struct netmem *nmem, long nr)
>  	return ret;
>  }
>
> -static inline long page_pool_defrag_page(struct page *page, long nr)
> -{
> -	return page_pool_defrag_netmem(page_netmem(page), nr);
> -}
> -
>  static inline bool page_pool_is_last_frag(struct page_pool *pool,
>  					  struct netmem *nmem)
>  {
> diff --git a/net/core/page_pool.c b/net/core/page_pool.c
> index ddf9f2bb85f7..5624cdae1f4e 100644
> --- a/net/core/page_pool.c
> +++ b/net/core/page_pool.c
> @@ -222,12 +222,6 @@ EXPORT_SYMBOL(page_pool_create);
>
>  static void page_pool_return_netmem(struct page_pool *pool, struct netmem *nm);
>
> -static inline
> -void page_pool_return_page(struct page_pool *pool, struct page *page)
> -{
> -	page_pool_return_netmem(pool, page_netmem(page));
> -}
> -
>  noinline
>  static struct netmem *page_pool_refill_alloc_cache(struct page_pool *pool)
>  {
> @@ -665,10 +659,9 @@ void page_pool_put_page_bulk(struct page_pool *pool, void **data,
>  }
>  EXPORT_SYMBOL(page_pool_put_page_bulk);
>
> -static struct page *page_pool_drain_frag(struct page_pool *pool,
> -					 struct page *page)
> +static struct netmem *page_pool_drain_frag(struct page_pool *pool,
> +					 struct netmem *nmem)
>  {
> -	struct netmem *nmem = page_netmem(page);
>  	long drain_count = BIAS_MAX - pool->frag_users;
>
>  	/* Some user is still using the page frag */
> @@ -679,7 +672,7 @@ static struct page *page_pool_drain_frag(struct page_pool *pool,
>  		if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)
>  			page_pool_dma_sync_for_device(pool, nmem, -1);
>
> -		return page;
> +		return nmem;
>  	}
>
>  	page_pool_return_netmem(pool, nmem);
> @@ -689,22 +682,22 @@ static struct page *page_pool_drain_frag(struct page_pool *pool,
>  static void page_pool_free_frag(struct page_pool *pool)
>  {
>  	long drain_count = BIAS_MAX - pool->frag_users;
> -	struct page *page = pool->frag_page;
> +	struct netmem *nmem = pool->frag_nmem;
>
> -	pool->frag_page = NULL;
> +	pool->frag_nmem = NULL;
>
> -	if (!page || page_pool_defrag_page(page, drain_count))
> +	if (!nmem || page_pool_defrag_netmem(nmem, drain_count))
>  		return;
>
> -	page_pool_return_page(pool, page);
> +	page_pool_return_netmem(pool, nmem);
>  }
>
> -struct page *page_pool_alloc_frag(struct page_pool *pool,
> +struct netmem *page_pool_alloc_frag(struct page_pool *pool,
>  				  unsigned int *offset,
>  				  unsigned int size, gfp_t gfp)
>  {
>  	unsigned int max_size = PAGE_SIZE << pool->p.order;
> -	struct page *page = pool->frag_page;
> +	struct netmem *nmem = pool->frag_nmem;
>
>  	if (WARN_ON(!(pool->p.flags & PP_FLAG_PAGE_FRAG) ||
>  		    size > max_size))
> @@ -713,35 +706,35 @@ struct page *page_pool_alloc_frag(struct page_pool *pool,
>  	size = ALIGN(size, dma_get_cache_alignment());
>  	*offset = pool->frag_offset;
>
> -	if (page && *offset + size > max_size) {
> -		page = page_pool_drain_frag(pool, page);
> -		if (page) {
> +	if (nmem && *offset + size > max_size) {
> +		nmem = page_pool_drain_frag(pool, nmem);
> +		if (nmem) {
>  			alloc_stat_inc(pool, fast);
>  			goto frag_reset;
>  		}
>  	}
>
> -	if (!page) {
> -		page = page_pool_alloc_pages(pool, gfp);
> -		if (unlikely(!page)) {
> -			pool->frag_page = NULL;
> +	if (!nmem) {
> +		nmem = page_pool_alloc_netmem(pool, gfp);
> +		if (unlikely(!nmem)) {
> +			pool->frag_nmem = NULL;
>  			return NULL;
>  		}
>
> -		pool->frag_page = page;
> +		pool->frag_nmem = nmem;
>
>  frag_reset:
>  		pool->frag_users = 1;
>  		*offset = 0;
>  		pool->frag_offset = size;
> -		page_pool_fragment_page(page, BIAS_MAX);
> -		return page;
> +		page_pool_fragment_netmem(nmem, BIAS_MAX);
> +		return nmem;
>  	}
>
>  	pool->frag_users++;
>  	pool->frag_offset = *offset + size;
>  	alloc_stat_inc(pool, fast);
> -	return page;
> +	return nmem;
>  }
>  EXPORT_SYMBOL(page_pool_alloc_frag);
>
> --
> 2.35.1
>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>