Merge branch 'net-consolidate-page_is_pfmemalloc-usage'

Alexander Lobakin says:

====================
net: consolidate page_is_pfmemalloc() usage

page_is_pfmemalloc() is used mostly by networking drivers to test
if a page can be considered for reusing/recycling.
It doesn't write anything to the struct page itself, so its sole
argument can be constified, as well as the first argument of
skb_propagate_pfmemalloc().
In Page Pool core code, it can be simply inlined instead.
Most of the callers from NIC drivers were just doppelgangers of
the same condition tests. Derive them into a new common function
do deduplicate the code.

Resend of v3 [2]:
 - it missed Patchwork and Netdev archives, probably due to server-side
   issues.

Since v2 [1]:
 - use more intuitive name for the new inline function since there's
   nothing "reserved" in remote pages (Jakub Kicinski, John Hubbard);
 - fold likely() inside the helper itself to make driver code a bit
   fancier (Jakub Kicinski);
 - split function introduction and using into two separate commits;
 - collect some more tags (Jesse Brandeburg, David Rientjes).

Since v1 [0]:
 - new: reduce code duplication by introducing a new common function
   to test if a page can be reused/recycled (David Rientjes);
 - collect autographs for Page Pool bits (Jesper Dangaard Brouer,
   Ilias Apalodimas).

[0] https://lore.kernel.org/netdev/20210125164612.243838-1-alobakin@pm.me
[1] https://lore.kernel.org/netdev/20210127201031.98544-1-alobakin@pm.me
[2] https://lore.kernel.org/lkml/20210131120844.7529-1-alobakin@pm.me
====================

Link: https://lore.kernel.org/r/20210202133030.5760-1-alobakin@pm.me
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

drivers/net/ethernet/hisilicon/hns3/hns3_enet.c

@@ -2800,12 +2800,6 @@ static void hns3_nic_alloc_rx_buffers(struct hns3_enet_ring *ring,
 	writel(i, ring->tqp->io_base + HNS3_RING_RX_RING_HEAD_REG);
 }
 
-static bool hns3_page_is_reusable(struct page *page)
-{
-	return page_to_nid(page) == numa_mem_id() &&
-		!page_is_pfmemalloc(page);
-}
-
 static bool hns3_can_reuse_page(struct hns3_desc_cb *cb)
 {
 	return (page_count(cb->priv) - cb->pagecnt_bias) == 1;
@@ -2823,10 +2817,11 @@ static void hns3_nic_reuse_page(struct sk_buff *skb, int i,
 	skb_add_rx_frag(skb, i, desc_cb->priv, desc_cb->page_offset + pull_len,
 			size - pull_len, truesize);
 
-	/* Avoid re-using remote pages, or the stack is still using the page
-	 * when page_offset rollback to zero, flag default unreuse
+	/* Avoid re-using remote and pfmemalloc pages, or the stack is still
+	 * using the page when page_offset rollback to zero, flag default
+	 * unreuse
 	 */
-	if (unlikely(!hns3_page_is_reusable(desc_cb->priv)) ||
+	if (!dev_page_is_reusable(desc_cb->priv) ||
 	    (!desc_cb->page_offset && !hns3_can_reuse_page(desc_cb))) {
 		__page_frag_cache_drain(desc_cb->priv, desc_cb->pagecnt_bias);
 		return;
@@ -3083,8 +3078,8 @@ static int hns3_alloc_skb(struct hns3_enet_ring *ring, unsigned int length,
 	if (length <= HNS3_RX_HEAD_SIZE) {
 		memcpy(__skb_put(skb, length), va, ALIGN(length, sizeof(long)));
 
-		/* We can reuse buffer as-is, just make sure it is local */
-		if (likely(hns3_page_is_reusable(desc_cb->priv)))
+		/* We can reuse buffer as-is, just make sure it is reusable */
+		if (dev_page_is_reusable(desc_cb->priv))
 			desc_cb->reuse_flag = 1;
 		else /* This page cannot be reused so discard it */
 			__page_frag_cache_drain(desc_cb->priv,

drivers/net/ethernet/intel/fm10k/fm10k_main.c

@@ -194,17 +194,12 @@ static void fm10k_reuse_rx_page(struct fm10k_ring *rx_ring,
 					 DMA_FROM_DEVICE);
 }
 
-static inline bool fm10k_page_is_reserved(struct page *page)
-{
-	return (page_to_nid(page) != numa_mem_id()) || page_is_pfmemalloc(page);
-}
-
 static bool fm10k_can_reuse_rx_page(struct fm10k_rx_buffer *rx_buffer,
 				    struct page *page,
 				    unsigned int __maybe_unused truesize)
 {
-	/* avoid re-using remote pages */
-	if (unlikely(fm10k_page_is_reserved(page)))
+	/* avoid re-using remote and pfmemalloc pages */
+	if (!dev_page_is_reusable(page))
 		return false;
 
 #if (PAGE_SIZE < 8192)
@@ -265,8 +260,8 @@ static bool fm10k_add_rx_frag(struct fm10k_rx_buffer *rx_buffer,
 	if (likely(size <= FM10K_RX_HDR_LEN)) {
 		memcpy(__skb_put(skb, size), va, ALIGN(size, sizeof(long)));
 
-		/* page is not reserved, we can reuse buffer as-is */
-		if (likely(!fm10k_page_is_reserved(page)))
+		/* page is reusable, we can reuse buffer as-is */
+		if (dev_page_is_reusable(page))
 			return true;
 
 		/* this page cannot be reused so discard it */

drivers/net/ethernet/intel/i40e/i40e_txrx.c

@@ -1843,19 +1843,6 @@ static bool i40e_cleanup_headers(struct i40e_ring *rx_ring, struct sk_buff *skb,
 	return false;
 }
 
-/**
- * i40e_page_is_reusable - check if any reuse is possible
- * @page: page struct to check
- *
- * A page is not reusable if it was allocated under low memory
- * conditions, or it's not in the same NUMA node as this CPU.
- */
-static inline bool i40e_page_is_reusable(struct page *page)
-{
-	return (page_to_nid(page) == numa_mem_id()) &&
-		!page_is_pfmemalloc(page);
-}
-
 /**
  * i40e_can_reuse_rx_page - Determine if this page can be reused by
  * the adapter for another receive
@@ -1891,7 +1878,7 @@ static bool i40e_can_reuse_rx_page(struct i40e_rx_buffer *rx_buffer,
 	struct page *page = rx_buffer->page;
 
 	/* Is any reuse possible? */
-	if (unlikely(!i40e_page_is_reusable(page)))
+	if (!dev_page_is_reusable(page))
 		return false;
 
 #if (PAGE_SIZE < 8192)

drivers/net/ethernet/intel/iavf/iavf_txrx.c

@@ -1141,19 +1141,6 @@ static void iavf_reuse_rx_page(struct iavf_ring *rx_ring,
 	new_buff->pagecnt_bias	= old_buff->pagecnt_bias;
 }
 
-/**
- * iavf_page_is_reusable - check if any reuse is possible
- * @page: page struct to check
- *
- * A page is not reusable if it was allocated under low memory
- * conditions, or it's not in the same NUMA node as this CPU.
- */
-static inline bool iavf_page_is_reusable(struct page *page)
-{
-	return (page_to_nid(page) == numa_mem_id()) &&
-		!page_is_pfmemalloc(page);
-}
-
 /**
  * iavf_can_reuse_rx_page - Determine if this page can be reused by
  * the adapter for another receive
@@ -1187,7 +1174,7 @@ static bool iavf_can_reuse_rx_page(struct iavf_rx_buffer *rx_buffer)
 	struct page *page = rx_buffer->page;
 
 	/* Is any reuse possible? */
-	if (unlikely(!iavf_page_is_reusable(page)))
+	if (!dev_page_is_reusable(page))
 		return false;
 
 #if (PAGE_SIZE < 8192)

drivers/net/ethernet/intel/ice/ice_txrx.c

@@ -728,15 +728,6 @@ bool ice_alloc_rx_bufs(struct ice_ring *rx_ring, u16 cleaned_count)
 	return !!cleaned_count;
 }
 
-/**
- * ice_page_is_reserved - check if reuse is possible
- * @page: page struct to check
- */
-static bool ice_page_is_reserved(struct page *page)
-{
-	return (page_to_nid(page) != numa_mem_id()) || page_is_pfmemalloc(page);
-}
-
 /**
  * ice_rx_buf_adjust_pg_offset - Prepare Rx buffer for reuse
  * @rx_buf: Rx buffer to adjust
@@ -775,8 +766,8 @@ ice_can_reuse_rx_page(struct ice_rx_buf *rx_buf, int rx_buf_pgcnt)
 	unsigned int pagecnt_bias = rx_buf->pagecnt_bias;
 	struct page *page = rx_buf->page;
 
-	/* avoid re-using remote pages */
-	if (unlikely(ice_page_is_reserved(page)))
+	/* avoid re-using remote and pfmemalloc pages */
+	if (!dev_page_is_reusable(page))
 		return false;
 
 #if (PAGE_SIZE < 8192)

drivers/net/ethernet/intel/igb/igb_main.c

@@ -8215,18 +8215,13 @@ static void igb_reuse_rx_page(struct igb_ring *rx_ring,
 	new_buff->pagecnt_bias	= old_buff->pagecnt_bias;
 }
 
-static inline bool igb_page_is_reserved(struct page *page)
-{
-	return (page_to_nid(page) != numa_mem_id()) || page_is_pfmemalloc(page);
-}
-
 static bool igb_can_reuse_rx_page(struct igb_rx_buffer *rx_buffer)
 {
 	unsigned int pagecnt_bias = rx_buffer->pagecnt_bias;
 	struct page *page = rx_buffer->page;
 
-	/* avoid re-using remote pages */
-	if (unlikely(igb_page_is_reserved(page)))
+	/* avoid re-using remote and pfmemalloc pages */
+	if (!dev_page_is_reusable(page))
 		return false;
 
 #if (PAGE_SIZE < 8192)

drivers/net/ethernet/intel/igc/igc_main.c

@@ -1648,18 +1648,13 @@ static void igc_reuse_rx_page(struct igc_ring *rx_ring,
 	new_buff->pagecnt_bias	= old_buff->pagecnt_bias;
 }
 
-static inline bool igc_page_is_reserved(struct page *page)
-{
-	return (page_to_nid(page) != numa_mem_id()) || page_is_pfmemalloc(page);
-}
-
 static bool igc_can_reuse_rx_page(struct igc_rx_buffer *rx_buffer)
 {
 	unsigned int pagecnt_bias = rx_buffer->pagecnt_bias;
 	struct page *page = rx_buffer->page;
 
-	/* avoid re-using remote pages */
-	if (unlikely(igc_page_is_reserved(page)))
+	/* avoid re-using remote and pfmemalloc pages */
+	if (!dev_page_is_reusable(page))
 		return false;
 
 #if (PAGE_SIZE < 8192)

drivers/net/ethernet/intel/ixgbe/ixgbe_main.c

@@ -1940,19 +1940,14 @@ static void ixgbe_reuse_rx_page(struct ixgbe_ring *rx_ring,
 	new_buff->pagecnt_bias	= old_buff->pagecnt_bias;
 }
 
-static inline bool ixgbe_page_is_reserved(struct page *page)
-{
-	return (page_to_nid(page) != numa_mem_id()) || page_is_pfmemalloc(page);
-}
-
 static bool ixgbe_can_reuse_rx_page(struct ixgbe_rx_buffer *rx_buffer,
 				    int rx_buffer_pgcnt)
 {
 	unsigned int pagecnt_bias = rx_buffer->pagecnt_bias;
 	struct page *page = rx_buffer->page;
 
-	/* avoid re-using remote pages */
-	if (unlikely(ixgbe_page_is_reserved(page)))
+	/* avoid re-using remote and pfmemalloc pages */
+	if (!dev_page_is_reusable(page))
 		return false;
 
 #if (PAGE_SIZE < 8192)

drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c

@@ -781,18 +781,13 @@ static void ixgbevf_reuse_rx_page(struct ixgbevf_ring *rx_ring,
 	new_buff->pagecnt_bias = old_buff->pagecnt_bias;
 }
 
-static inline bool ixgbevf_page_is_reserved(struct page *page)
-{
-	return (page_to_nid(page) != numa_mem_id()) || page_is_pfmemalloc(page);
-}
-
 static bool ixgbevf_can_reuse_rx_page(struct ixgbevf_rx_buffer *rx_buffer)
 {
 	unsigned int pagecnt_bias = rx_buffer->pagecnt_bias;
 	struct page *page = rx_buffer->page;
 
-	/* avoid re-using remote pages */
-	if (unlikely(ixgbevf_page_is_reserved(page)))
+	/* avoid re-using remote and pfmemalloc pages */
+	if (!dev_page_is_reusable(page))
 		return false;
 
 #if (PAGE_SIZE < 8192)

drivers/net/ethernet/mellanox/mlx5/core/en_rx.c

@@ -213,11 +213,6 @@ static inline u32 mlx5e_decompress_cqes_start(struct mlx5e_rq *rq,
 	return mlx5e_decompress_cqes_cont(rq, wq, 1, budget_rem) - 1;
 }
 
-static inline bool mlx5e_page_is_reserved(struct page *page)
-{
-	return page_is_pfmemalloc(page) || page_to_nid(page) != numa_mem_id();
-}
-
 static inline bool mlx5e_rx_cache_put(struct mlx5e_rq *rq,
 				      struct mlx5e_dma_info *dma_info)
 {
@@ -230,7 +225,7 @@ static inline bool mlx5e_rx_cache_put(struct mlx5e_rq *rq,
 		return false;
 	}
 
-	if (unlikely(mlx5e_page_is_reserved(dma_info->page))) {
+	if (!dev_page_is_reusable(dma_info->page)) {
 		stats->cache_waive++;
 		return false;
 	}

include/linux/mm.h

@@ -1584,7 +1584,7 @@ struct address_space *page_mapping_file(struct page *page);
  * ALLOC_NO_WATERMARKS and the low watermark was not
  * met implying that the system is under some pressure.
  */
-static inline bool page_is_pfmemalloc(struct page *page)
+static inline bool page_is_pfmemalloc(const struct page *page)
 {
 	/*
 	 * Page index cannot be this large so this must be

include/linux/skbuff.h

@@ -2938,13 +2938,29 @@ static inline struct page *dev_alloc_page(void)
 	return dev_alloc_pages(0);
 }
 
+/**
+ * dev_page_is_reusable - check whether a page can be reused for network Rx
+ * @page: the page to test
+ *
+ * A page shouldn't be considered for reusing/recycling if it was allocated
+ * under memory pressure or at a distant memory node.
+ *
+ * Returns false if this page should be returned to page allocator, true
+ * otherwise.
+ */
+static inline bool dev_page_is_reusable(const struct page *page)
+{
+	return likely(page_to_nid(page) == numa_mem_id() &&
+		      !page_is_pfmemalloc(page));
+}
+
 /**
  *	skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page
  *	@page: The page that was allocated from skb_alloc_page
  *	@skb: The skb that may need pfmemalloc set
  */
-static inline void skb_propagate_pfmemalloc(struct page *page,
-					     struct sk_buff *skb)
+static inline void skb_propagate_pfmemalloc(const struct page *page,
+					    struct sk_buff *skb)
 {
 	if (page_is_pfmemalloc(page))
 		skb->pfmemalloc = true;

net/core/page_pool.c

@@ -350,14 +350,6 @@ static bool page_pool_recycle_in_cache(struct page *page,
 	return true;
 }
 
-/* page is NOT reusable when:
- * 1) allocated when system is under some pressure. (page_is_pfmemalloc)
- */
-static bool pool_page_reusable(struct page_pool *pool, struct page *page)
-{
-	return !page_is_pfmemalloc(page);
-}
-
 /* If the page refcnt == 1, this will try to recycle the page.
  * if PP_FLAG_DMA_SYNC_DEV is set, we'll try to sync the DMA area for
  * the configured size min(dma_sync_size, pool->max_len).
@@ -373,9 +365,11 @@ __page_pool_put_page(struct page_pool *pool, struct page *page,
 	 * regular page allocator APIs.
 	 *
 	 * refcnt == 1 means page_pool owns page, and can recycle it.
+	 *
+	 * page is NOT reusable when allocated when system is under
+	 * some pressure. (page_is_pfmemalloc)
 	 */
-	if (likely(page_ref_count(page) == 1 &&
-		   pool_page_reusable(pool, page))) {
+	if (likely(page_ref_count(page) == 1 && !page_is_pfmemalloc(page))) {
 		/* Read barrier done in page_ref_count / READ_ONCE */
 
 		if (pool->p.flags & PP_FLAG_DMA_SYNC_DEV)