[PATCH v2 net-next 0/4] net: consolidate page_is_pfmemalloc() usage

[PATCH v2 net-next 0/4] net: consolidate page_is_pfmemalloc() usage

[Alexander Lobakin]

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.

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

Alexander Lobakin (4):
  mm: constify page_is_pfmemalloc() argument
  skbuff: constify skb_propagate_pfmemalloc() "page" argument
  net: introduce common dev_page_is_reserved()
  net: page_pool: simplify page recycling condition tests

 .../net/ethernet/hisilicon/hns3/hns3_enet.c   | 10 ++--------
 drivers/net/ethernet/intel/fm10k/fm10k_main.c |  9 ++-------
 drivers/net/ethernet/intel/i40e/i40e_txrx.c   | 15 +--------------
 drivers/net/ethernet/intel/iavf/iavf_txrx.c   | 15 +--------------
 drivers/net/ethernet/intel/ice/ice_txrx.c     | 11 +----------
 drivers/net/ethernet/intel/igb/igb_main.c     |  7 +------
 drivers/net/ethernet/intel/igc/igc_main.c     |  7 +------
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c |  7 +------
 .../net/ethernet/intel/ixgbevf/ixgbevf_main.c |  7 +------
 .../net/ethernet/mellanox/mlx5/core/en_rx.c   |  7 +------
 include/linux/mm.h                            |  2 +-
 include/linux/skbuff.h                        | 19 +++++++++++++++++--
 net/core/page_pool.c                          | 14 ++++----------
 13 files changed, 34 insertions(+), 96 deletions(-)

-- 
2.30.0

[PATCH v2 net-next 1/4] mm: constify page_is_pfmemalloc() argument

[Alexander Lobakin]

The function only tests for page->index, so its argument should be
const.

Signed-off-by: Alexander Lobakin <alobakin@pm.me>
---
 include/linux/mm.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index ecdf8a8cd6ae..078633d43af9 100644
--- a/include/linux/mm.h
+++ b/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
-- 
2.30.0

Re: [PATCH v2 net-next 1/4] mm: constify page_is_pfmemalloc() argument

[David Rientjes]

On Wed, 27 Jan 2021, Alexander Lobakin wrote:

> The function only tests for page->index, so its argument should be
> const.
> 
> Signed-off-by: Alexander Lobakin <alobakin@pm.me>

Acked-by: David Rientjes <rientjes@google.com>

Re: [PATCH v2 net-next 1/4] mm: constify page_is_pfmemalloc() argument

[Jakub Kicinski]

On Wed, 27 Jan 2021 20:11:01 +0000 Alexander Lobakin wrote:
> The function only tests for page->index, so its argument should be
> const.
> 
> Signed-off-by: Alexander Lobakin <alobakin@pm.me>
> ---
>  include/linux/mm.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index ecdf8a8cd6ae..078633d43af9 100644
> --- a/include/linux/mm.h
> +++ b/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

No objections for this going via net-next?

[PATCH v2 net-next 2/4] skbuff: constify skb_propagate_pfmemalloc() "page" argument

[Alexander Lobakin]

The function doesn't write anything to the page struct itself,
so this argument can be const.

Misc: align second argument to the brace while at it.

Signed-off-by: Alexander Lobakin <alobakin@pm.me>
---
 include/linux/skbuff.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index 9313b5aaf45b..b027526da4f9 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2943,8 +2943,8 @@ static inline struct page *dev_alloc_page(void)
  *	@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;
-- 
2.30.0

Re: [PATCH v2 net-next 2/4] skbuff: constify skb_propagate_pfmemalloc() "page" argument

[David Rientjes]

On Wed, 27 Jan 2021, Alexander Lobakin wrote:

> The function doesn't write anything to the page struct itself,
> so this argument can be const.
> 
> Misc: align second argument to the brace while at it.
> 
> Signed-off-by: Alexander Lobakin <alobakin@pm.me>

Acked-by: David Rientjes <rientjes@google.com>

[PATCH v2 net-next 3/4] net: introduce common dev_page_is_reserved()

[Alexander Lobakin]

A bunch of drivers test the page before reusing/recycling for two
common conditions:
 - if a page was allocated under memory pressure (pfmemalloc page);
 - if a page was allocated at a distant memory node (to exclude
   slowdowns).

Introduce and use a new common function for doing this and eliminate
all functions-duplicates from drivers.

Suggested-by: David Rientjes <rientjes@google.com>
Signed-off-by: Alexander Lobakin <alobakin@pm.me>
---
 drivers/net/ethernet/hisilicon/hns3/hns3_enet.c   | 10 ++--------
 drivers/net/ethernet/intel/fm10k/fm10k_main.c     |  9 ++-------
 drivers/net/ethernet/intel/i40e/i40e_txrx.c       | 15 +--------------
 drivers/net/ethernet/intel/iavf/iavf_txrx.c       | 15 +--------------
 drivers/net/ethernet/intel/ice/ice_txrx.c         | 11 +----------
 drivers/net/ethernet/intel/igb/igb_main.c         |  7 +------
 drivers/net/ethernet/intel/igc/igc_main.c         |  7 +------
 drivers/net/ethernet/intel/ixgbe/ixgbe_main.c     |  7 +------
 drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |  7 +------
 drivers/net/ethernet/mellanox/mlx5/core/en_rx.c   |  7 +------
 include/linux/skbuff.h                            | 15 +++++++++++++++
 11 files changed, 27 insertions(+), 83 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index 512080640cbc..f71e3d963750 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/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;
@@ -2826,7 +2820,7 @@ static void hns3_nic_reuse_page(struct sk_buff *skb, int i,
 	/* Avoid re-using remote 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 (unlikely(dev_page_is_reserved(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;
@@ -3084,7 +3078,7 @@ static int hns3_alloc_skb(struct hns3_enet_ring *ring, unsigned int length,
 		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)))
+		if (likely(!dev_page_is_reserved(desc_cb->priv)))
 			desc_cb->reuse_flag = 1;
 		else /* This page cannot be reused so discard it */
 			__page_frag_cache_drain(desc_cb->priv,
diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_main.c b/drivers/net/ethernet/intel/fm10k/fm10k_main.c
index 99b8252eb969..9f547dd8c914 100644
--- a/drivers/net/ethernet/intel/fm10k/fm10k_main.c
+++ b/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)))
+	if (unlikely(dev_page_is_reserved(page)))
 		return false;
 
 #if (PAGE_SIZE < 8192)
@@ -266,7 +261,7 @@ static bool fm10k_add_rx_frag(struct fm10k_rx_buffer *rx_buffer,
 		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)))
+		if (likely(!dev_page_is_reserved(page)))
 			return true;
 
 		/* this page cannot be reused so discard it */
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index 2574e78f7597..4c295671aa09 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/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 (unlikely(dev_page_is_reserved(page)))
 		return false;
 
 #if (PAGE_SIZE < 8192)
diff --git a/drivers/net/ethernet/intel/iavf/iavf_txrx.c b/drivers/net/ethernet/intel/iavf/iavf_txrx.c
index 256fa07d54d5..a6b552465f03 100644
--- a/drivers/net/ethernet/intel/iavf/iavf_txrx.c
+++ b/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 (unlikely(dev_page_is_reserved(page)))
 		return false;
 
 #if (PAGE_SIZE < 8192)
diff --git a/drivers/net/ethernet/intel/ice/ice_txrx.c b/drivers/net/ethernet/intel/ice/ice_txrx.c
index 422f53997c02..623bbd27870f 100644
--- a/drivers/net/ethernet/intel/ice/ice_txrx.c
+++ b/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
@@ -776,7 +767,7 @@ ice_can_reuse_rx_page(struct ice_rx_buf *rx_buf, int rx_buf_pgcnt)
 	struct page *page = rx_buf->page;
 
 	/* avoid re-using remote pages */
-	if (unlikely(ice_page_is_reserved(page)))
+	if (unlikely(dev_page_is_reserved(page)))
 		return false;
 
 #if (PAGE_SIZE < 8192)
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 84d4284b8b32..f3020a73323d 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/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)))
+	if (unlikely(dev_page_is_reserved(page)))
 		return false;
 
 #if (PAGE_SIZE < 8192)
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index 43aec42e6d9d..8d51fb86be2e 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/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)))
+	if (unlikely(dev_page_is_reserved(page)))
 		return false;
 
 #if (PAGE_SIZE < 8192)
diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
index e08c01525fd2..37cc117c3aa6 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
@@ -1940,11 +1940,6 @@ 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)
 {
@@ -1952,7 +1947,7 @@ static bool ixgbe_can_reuse_rx_page(struct ixgbe_rx_buffer *rx_buffer,
 	struct page *page = rx_buffer->page;
 
 	/* avoid re-using remote pages */
-	if (unlikely(ixgbe_page_is_reserved(page)))
+	if (unlikely(dev_page_is_reserved(page)))
 		return false;
 
 #if (PAGE_SIZE < 8192)
diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index a14e55e7fce8..24caa0d2d572 100644
--- a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
+++ b/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)))
+	if (unlikely(dev_page_is_reserved(page)))
 		return false;
 
 #if (PAGE_SIZE < 8192)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
index dec93d57542f..5b9fb979adc6 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
@@ -212,11 +212,6 @@ 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)
 {
@@ -229,7 +224,7 @@ static inline bool mlx5e_rx_cache_put(struct mlx5e_rq *rq,
 		return false;
 	}
 
-	if (unlikely(mlx5e_page_is_reserved(dma_info->page))) {
+	if (unlikely(dev_page_is_reserved(dma_info->page))) {
 		stats->cache_waive++;
 		return false;
 	}
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index b027526da4f9..688782513d09 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2938,6 +2938,21 @@ static inline struct page *dev_alloc_page(void)
 	return dev_alloc_pages(0);
 }
 
+/**
+ * dev_page_is_reserved - 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 true if this page should be returned to page allocator, false
+ * otherwise.
+ */
+static inline bool dev_page_is_reserved(const struct page *page)
+{
+	return page_is_pfmemalloc(page) || page_to_nid(page) != numa_mem_id();
+}
+
 /**
  *	skb_propagate_pfmemalloc - Propagate pfmemalloc if skb is allocated after RX page
  *	@page: The page that was allocated from skb_alloc_page
-- 
2.30.0

Re: [PATCH v2 net-next 3/4] net: introduce common dev_page_is_reserved()

[Jesse Brandeburg]

Alexander Lobakin wrote:

> A bunch of drivers test the page before reusing/recycling for two
> common conditions:
>  - if a page was allocated under memory pressure (pfmemalloc page);
>  - if a page was allocated at a distant memory node (to exclude
>    slowdowns).
> 
> Introduce and use a new common function for doing this and eliminate
> all functions-duplicates from drivers.
> 
> Suggested-by: David Rientjes <rientjes@google.com>
> Signed-off-by: Alexander Lobakin <alobakin@pm.me>
> ---
>  drivers/net/ethernet/hisilicon/hns3/hns3_enet.c   | 10 ++--------
>  drivers/net/ethernet/intel/fm10k/fm10k_main.c     |  9 ++-------
>  drivers/net/ethernet/intel/i40e/i40e_txrx.c       | 15 +--------------
>  drivers/net/ethernet/intel/iavf/iavf_txrx.c       | 15 +--------------
>  drivers/net/ethernet/intel/ice/ice_txrx.c         | 11 +----------
>  drivers/net/ethernet/intel/igb/igb_main.c         |  7 +------
>  drivers/net/ethernet/intel/igc/igc_main.c         |  7 +------
>  drivers/net/ethernet/intel/ixgbe/ixgbe_main.c     |  7 +------
>  drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c |  7 +------
>  drivers/net/ethernet/mellanox/mlx5/core/en_rx.c   |  7 +------
>  include/linux/skbuff.h                            | 15 +++++++++++++++
>  11 files changed, 27 insertions(+), 83 deletions(-)

For the patch, and esp. for the Intel drivers:
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>

Re: [PATCH v2 net-next 3/4] net: introduce common dev_page_is_reserved()

[David Rientjes]

On Wed, 27 Jan 2021, Alexander Lobakin wrote:

> A bunch of drivers test the page before reusing/recycling for two
> common conditions:
>  - if a page was allocated under memory pressure (pfmemalloc page);
>  - if a page was allocated at a distant memory node (to exclude
>    slowdowns).
> 
> Introduce and use a new common function for doing this and eliminate
> all functions-duplicates from drivers.
> 
> Suggested-by: David Rientjes <rientjes@google.com>
> Signed-off-by: Alexander Lobakin <alobakin@pm.me>

Looks even better than I thought!

(Since all of the changes are in drivers/net/ethernet/, I assume 
everything directly or indirectly includes skbuff.h already.)

Acked-by: David Rientjes <rientjes@google.com>

Thanks for doing this.

Re: [PATCH v2 net-next 3/4] net: introduce common dev_page_is_reserved()

[Jakub Kicinski]

On Wed, 27 Jan 2021 20:11:23 +0000 Alexander Lobakin wrote:
> + * dev_page_is_reserved - 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 true if this page should be returned to page allocator, false
> + * otherwise.
> + */
> +static inline bool dev_page_is_reserved(const struct page *page)

Am I the only one who feels like "reusable" is a better term than
"reserved".

Re: [PATCH v2 net-next 3/4] net: introduce common dev_page_is_reserved()

[Alexander Lobakin]

From: Jakub Kicinski <kuba@kernel.org>
Date: Fri, 29 Jan 2021 18:39:07 -0800

> On Wed, 27 Jan 2021 20:11:23 +0000 Alexander Lobakin wrote:
> > + * dev_page_is_reserved - 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 true if this page should be returned to page allocator, false
> > + * otherwise.
> > + */
> > +static inline bool dev_page_is_reserved(const struct page *page)
> 
> Am I the only one who feels like "reusable" is a better term than
> "reserved".

I thought about it, but this will need to inverse the conditions in
most of the drivers. I decided to keep it as it is.
I can redo if "reusable" is preferred.

Regarding "no objectives to take patch 1 through net-next": patches
2-3 depend on it, so I can't put it in a separate series.

Thanks,
Al

Re: [PATCH v2 net-next 3/4] net: introduce common dev_page_is_reserved()

[Jakub Kicinski]

On Sat, 30 Jan 2021 15:42:29 +0000 Alexander Lobakin wrote:
> > On Wed, 27 Jan 2021 20:11:23 +0000 Alexander Lobakin wrote:  
> > > + * dev_page_is_reserved - 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 true if this page should be returned to page allocator, false
> > > + * otherwise.
> > > + */
> > > +static inline bool dev_page_is_reserved(const struct page *page)  
> > 
> > Am I the only one who feels like "reusable" is a better term than
> > "reserved".  
> 
> I thought about it, but this will need to inverse the conditions in
> most of the drivers. I decided to keep it as it is.
> I can redo if "reusable" is preferred.

Naming is hard. As long as the condition is not a double negative it
reads fine to me, but that's probably personal preference.
The thing that doesn't sit well is the fact that there is nothing
"reserved" about a page from another NUMA node.. But again, if nobody
+1s this it's whatever...

That said can we move the likely()/unlikely() into the helper itself?
People on the internet may say otherwise but according to my tests 
using __builtin_expect() on a return value of a static inline helper
works just fine.

Re: [PATCH v2 net-next 3/4] net: introduce common dev_page_is_reserved()

[Alexander Lobakin]

From: Jakub Kicinski <kuba@kernel.org>
Date: Sat, 30 Jan 2021 11:07:07 -0800

> On Sat, 30 Jan 2021 15:42:29 +0000 Alexander Lobakin wrote:
> > > On Wed, 27 Jan 2021 20:11:23 +0000 Alexander Lobakin wrote:
> > > > + * dev_page_is_reserved - 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 true if this page should be returned to page allocator, false
> > > > + * otherwise.
> > > > + */
> > > > +static inline bool dev_page_is_reserved(const struct page *page)
> > >
> > > Am I the only one who feels like "reusable" is a better term than
> > > "reserved".
> >
> > I thought about it, but this will need to inverse the conditions in
> > most of the drivers. I decided to keep it as it is.
> > I can redo if "reusable" is preferred.
> 
> Naming is hard. As long as the condition is not a double negative it
> reads fine to me, but that's probably personal preference.
> The thing that doesn't sit well is the fact that there is nothing
> "reserved" about a page from another NUMA node.. But again, if nobody
> +1s this it's whatever...

Agree on NUMA and naming. I'm a bit surprised that 95% of drivers
have this helper called "reserved" (one of the reasons why I finished
with this variant).
Let's say, if anybody else will vote for "reusable", I'll pick it for
v3.

> That said can we move the likely()/unlikely() into the helper itself?
> People on the internet may say otherwise but according to my tests
> using __builtin_expect() on a return value of a static inline helper
> works just fine.

Sounds fine, this will make code more elegant. Will publish v3 soon.

Thanks,
Al

Re: [PATCH v2 net-next 3/4] net: introduce common dev_page_is_reserved()

[John Hubbard]

On 1/30/21 11:45 AM, Alexander Lobakin wrote:
> From: Jakub Kicinski <kuba@kernel.org>
> Date: Sat, 30 Jan 2021 11:07:07 -0800
> 
>> On Sat, 30 Jan 2021 15:42:29 +0000 Alexander Lobakin wrote:
>>>> On Wed, 27 Jan 2021 20:11:23 +0000 Alexander Lobakin wrote:
>>>>> + * dev_page_is_reserved - 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 true if this page should be returned to page allocator, false
>>>>> + * otherwise.
>>>>> + */
>>>>> +static inline bool dev_page_is_reserved(const struct page *page)
>>>>
>>>> Am I the only one who feels like "reusable" is a better term than
>>>> "reserved".
>>>
>>> I thought about it, but this will need to inverse the conditions in
>>> most of the drivers. I decided to keep it as it is.
>>> I can redo if "reusable" is preferred.
>>
>> Naming is hard. As long as the condition is not a double negative it
>> reads fine to me, but that's probably personal preference.
>> The thing that doesn't sit well is the fact that there is nothing
>> "reserved" about a page from another NUMA node.. But again, if nobody
>> +1s this it's whatever...
> 
> Agree on NUMA and naming. I'm a bit surprised that 95% of drivers
> have this helper called "reserved" (one of the reasons why I finished
> with this variant).
> Let's say, if anybody else will vote for "reusable", I'll pick it for
> v3.

Definitely "reusable" seems better to me, and especially anything *other*
than "reserved" is a good idea, IMHO.


thanks,
-- 
John Hubbard
NVIDIA

[PATCH v2 net-next 4/4] net: page_pool: simplify page recycling condition tests

[Alexander Lobakin]

pool_page_reusable() is a leftover from pre-NUMA-aware times. For now,
this function is just a redundant wrapper over page_is_pfmemalloc(),
so Inline it into its sole call site.

Signed-off-by: Alexander Lobakin <alobakin@pm.me>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
---
 net/core/page_pool.c | 14 ++++----------
 1 file changed, 4 insertions(+), 10 deletions(-)

diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index f3c690b8c8e3..ad8b0707af04 100644
--- a/net/core/page_pool.c
+++ b/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)
-- 
2.30.0

Re: [PATCH v2 net-next 4/4] net: page_pool: simplify page recycling condition tests

[David Rientjes]

On Wed, 27 Jan 2021, Alexander Lobakin wrote:

> pool_page_reusable() is a leftover from pre-NUMA-aware times. For now,
> this function is just a redundant wrapper over page_is_pfmemalloc(),
> so Inline it into its sole call site.
> 
> Signed-off-by: Alexander Lobakin <alobakin@pm.me>
> Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
> Reviewed-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>

Acked-by: David Rientjes <rientjes@google.com>

Re: [PATCH v2 net-next 0/4] net: consolidate page_is_pfmemalloc() usage

[Jesse Brandeburg]

Alexander Lobakin wrote:

> 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.

This is a useful cleanup! Thanks.

For the series:
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>