2021-02-02 21:40:19

by Alexander Lobakin

[permalink] [raw]
Subject: [PATCH RESEND v3 net-next 0/5] 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/[email protected]
[1] https://lore.kernel.org/netdev/[email protected]
[2] https://lore.kernel.org/lkml/[email protected]

Alexander Lobakin (5):
mm: constify page_is_pfmemalloc() argument
skbuff: constify skb_propagate_pfmemalloc() "page" argument
net: introduce common dev_page_is_reusable()
net: use the new dev_page_is_reusable() instead of private versions
net: page_pool: simplify page recycling condition tests

.../net/ethernet/hisilicon/hns3/hns3_enet.c | 17 ++++++----------
drivers/net/ethernet/intel/fm10k/fm10k_main.c | 13 ++++--------
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 | 13 ++----------
drivers/net/ethernet/intel/igb/igb_main.c | 9 ++-------
drivers/net/ethernet/intel/igc/igc_main.c | 9 ++-------
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 9 ++-------
.../net/ethernet/intel/ixgbevf/ixgbevf_main.c | 9 ++-------
.../net/ethernet/mellanox/mlx5/core/en_rx.c | 7 +------
include/linux/mm.h | 2 +-
include/linux/skbuff.h | 20 +++++++++++++++++--
net/core/page_pool.c | 14 ++++---------
13 files changed, 46 insertions(+), 106 deletions(-)

--
2.30.0



2021-02-02 21:40:22

by Alexander Lobakin

[permalink] [raw]
Subject: [PATCH RESEND v3 net-next 1/5] mm: constify page_is_pfmemalloc() argument

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

Signed-off-by: Alexander Lobakin <[email protected]>
Reviewed-by: Jesse Brandeburg <[email protected]>
Acked-by: David Rientjes <[email protected]>
---
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


2021-02-02 21:40:36

by Alexander Lobakin

[permalink] [raw]
Subject: [PATCH RESEND v3 net-next 3/5] net: introduce common dev_page_is_reusable()

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 a new common inline for doing this, with likely() already
folded inside to make driver code a bit simpler.

Suggested-by: David Rientjes <[email protected]>
Suggested-by: Jakub Kicinski <[email protected]>
Cc: John Hubbard <[email protected]>
Signed-off-by: Alexander Lobakin <[email protected]>
Reviewed-by: Jesse Brandeburg <[email protected]>
Acked-by: David Rientjes <[email protected]>
---
include/linux/skbuff.h | 16 ++++++++++++++++
1 file changed, 16 insertions(+)

diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index b027526da4f9..0e42c53b8ca9 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2938,6 +2938,22 @@ 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
--
2.30.0


2021-02-02 21:40:40

by Alexander Lobakin

[permalink] [raw]
Subject: [PATCH RESEND v3 net-next 4/5] net: use the new dev_page_is_reusable() instead of private versions

Now we can remove a bunch of identical functions from the drivers and
make them use common dev_page_is_reusable(). All {,un}likely() checks
are omitted since it's already present in this helper.
Also update some comments near the call sites.

Suggested-by: David Rientjes <[email protected]>
Suggested-by: Jakub Kicinski <[email protected]>
Cc: John Hubbard <[email protected]>
Signed-off-by: Alexander Lobakin <[email protected]>
---
drivers/net/ethernet/hisilicon/hns3/hns3_enet.c | 17 ++++++-----------
drivers/net/ethernet/intel/fm10k/fm10k_main.c | 13 ++++---------
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 | 13 ++-----------
drivers/net/ethernet/intel/igb/igb_main.c | 9 ++-------
drivers/net/ethernet/intel/igc/igc_main.c | 9 ++-------
drivers/net/ethernet/intel/ixgbe/ixgbe_main.c | 9 ++-------
.../net/ethernet/intel/ixgbevf/ixgbevf_main.c | 9 ++-------
drivers/net/ethernet/mellanox/mlx5/core/en_rx.c | 7 +------
10 files changed, 23 insertions(+), 93 deletions(-)

diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index 512080640cbc..f39f5b1c4cec 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;
@@ -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,
diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_main.c b/drivers/net/ethernet/intel/fm10k/fm10k_main.c
index 99b8252eb969..247f44f4cb30 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)))
+ /* 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 */
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index 2574e78f7597..8d2ea4293d69 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 (!dev_page_is_reusable(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..ffaf2742a2e0 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 (!dev_page_is_reusable(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 2c2de56e2824..8ca63c6a6ba4 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
@@ -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)
diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 84d4284b8b32..7d8e02b4d092 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)))
+ /* avoid re-using remote and pfmemalloc pages */
+ if (!dev_page_is_reusable(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..ae0de7f08568 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)))
+ /* avoid re-using remote and pfmemalloc pages */
+ if (!dev_page_is_reusable(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..237e09342f28 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_main.c
+++ b/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)
diff --git a/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c b/drivers/net/ethernet/intel/ixgbevf/ixgbevf_main.c
index a14e55e7fce8..449d7d5b280d 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)))
+ /* avoid re-using remote and pfmemalloc pages */
+ if (!dev_page_is_reusable(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 98b56f495b32..e1b4cf506a15 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/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;
}
--
2.30.0


2021-02-02 21:42:22

by Alexander Lobakin

[permalink] [raw]
Subject: [PATCH RESEND v3 net-next 2/5] skbuff: constify skb_propagate_pfmemalloc() "page" argument

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 <[email protected]>
Reviewed-by: Jesse Brandeburg <[email protected]>
Acked-by: David Rientjes <[email protected]>
---
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


2021-02-02 21:42:57

by Alexander Lobakin

[permalink] [raw]
Subject: [PATCH RESEND v3 net-next 5/5] net: page_pool: simplify page recycling condition tests

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 <[email protected]>
Acked-by: Jesper Dangaard Brouer <[email protected]>
Reviewed-by: Ilias Apalodimas <[email protected]>
Reviewed-by: Jesse Brandeburg <[email protected]>
Acked-by: David Rientjes <[email protected]>
---
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


2021-02-05 01:46:54

by Jesse Brandeburg

[permalink] [raw]
Subject: Re: [PATCH RESEND v3 net-next 4/5] net: use the new dev_page_is_reusable() instead of private versions

Alexander Lobakin wrote:

> Now we can remove a bunch of identical functions from the drivers and
> make them use common dev_page_is_reusable(). All {,un}likely() checks
> are omitted since it's already present in this helper.
> Also update some comments near the call sites.
>
> Suggested-by: David Rientjes <[email protected]>
> Suggested-by: Jakub Kicinski <[email protected]>
> Cc: John Hubbard <[email protected]>
> Signed-off-by: Alexander Lobakin <[email protected]>

I don't know why it was missed in the series update, but:
Reviewed-by: Jesse Brandeburg <[email protected]>

2021-02-05 02:43:47

by patchwork-bot+netdevbpf

[permalink] [raw]
Subject: Re: [PATCH RESEND v3 net-next 0/5] net: consolidate page_is_pfmemalloc() usage

Hello:

This series was applied to netdev/net-next.git (refs/heads/master):

On Tue, 02 Feb 2021 13:30:43 +0000 you 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.
>
> [...]

Here is the summary with links:
- [RESEND,v3,net-next,1/5] mm: constify page_is_pfmemalloc() argument
https://git.kernel.org/netdev/net-next/c/1d7bab6a9445
- [RESEND,v3,net-next,2/5] skbuff: constify skb_propagate_pfmemalloc() "page" argument
https://git.kernel.org/netdev/net-next/c/48f971c9c80a
- [RESEND,v3,net-next,3/5] net: introduce common dev_page_is_reusable()
https://git.kernel.org/netdev/net-next/c/bc38f30f8dbc
- [RESEND,v3,net-next,4/5] net: use the new dev_page_is_reusable() instead of private versions
https://git.kernel.org/netdev/net-next/c/a79afa78e625
- [RESEND,v3,net-next,5/5] net: page_pool: simplify page recycling condition tests
https://git.kernel.org/netdev/net-next/c/05656132a874

You are awesome, thank you!
--
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