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* [PATCH net-next v7 0/6] introduce page_pool_alloc() related API
@ 2023-08-16 10:01 Yunsheng Lin
  2023-08-16 10:01 ` [PATCH net-next v7 3/6] page_pool: remove PP_FLAG_PAGE_FRAG Yunsheng Lin
  0 siblings, 1 reply; 2+ messages in thread
From: Yunsheng Lin @ 2023-08-16 10:01 UTC (permalink / raw)
  To: davem, kuba, pabeni
  Cc: netdev, linux-kernel, Yunsheng Lin, Alexei Starovoitov,
	Daniel Borkmann, Jesper Dangaard Brouer, John Fastabend,
	Matthias Brugger, AngeloGioacchino Del Regno, bpf,
	linux-arm-kernel, linux-mediatek

In [1] & [2] & [3], there are usecases for veth and virtio_net
to use frag support in page pool to reduce memory usage, and it
may request different frag size depending on the head/tail
room space for xdp_frame/shinfo and mtu/packet size. When the
requested frag size is large enough that a single page can not
be split into more than one frag, using frag support only have
performance penalty because of the extra frag count handling
for frag support.

So this patchset provides a page pool API for the driver to
allocate memory with least memory utilization and performance
penalty when it doesn't know the size of memory it need
beforehand.

1. https://patchwork.kernel.org/project/netdevbpf/patch/d3ae6bd3537fbce379382ac6a42f67e22f27ece2.1683896626.git.lorenzo@kernel.org/
2. https://patchwork.kernel.org/project/netdevbpf/patch/20230526054621.18371-3-liangchen.linux@gmail.com/
3. https://github.com/alobakin/linux/tree/iavf-pp-frag

V7: Fix a compile error, a few typo and use kernel-doc syntax.

V6: Add a PP_FLAG_PAGE_SPLIT_IN_DRIVER flag to fail the page_pool
    creation for 32-bit arch with 64-bit DMA when driver tries to
    do the page splitting itself, adjust the requested size to
    include head/tail room in veth, and rebased on the latest
    next-net.

v5 RFC: Add a new page_pool_cache_alloc() API, and other minor
        change as discussed in v4. As there seems to be three
        comsumers that might be made use of the new API, so
        repost it as RFC and CC the relevant authors to see
        if the new API fits their need.

V4. Fix a typo and add a patch to update document about frag
    API, PAGE_POOL_DMA_USE_PP_FRAG_COUNT is not renamed yet
    as we may need a different thread to discuss that.

V3: Incorporate changes from the disscusion with Alexander,
    mostly the inline wraper, PAGE_POOL_DMA_USE_PP_FRAG_COUNT
    change split to separate patch and comment change.
V2: Add patch to remove PP_FLAG_PAGE_FRAG flags and mention
    virtio_net usecase in the cover letter.
V1: Drop RFC tag and page_pool_frag patch.

Yunsheng Lin (6):
  page_pool: frag API support for 32-bit arch with 64-bit DMA
  page_pool: unify frag_count handling in page_pool_is_last_frag()
  page_pool: remove PP_FLAG_PAGE_FRAG
  page_pool: introduce page_pool[_cache]_alloc() API
  page_pool: update document about frag API
  net: veth: use newly added page pool API for veth with xdp

 Documentation/networking/page_pool.rst        |   4 +-
 drivers/net/ethernet/broadcom/bnxt/bnxt.c     |   2 -
 .../net/ethernet/hisilicon/hns3/hns3_enet.c   |   3 +-
 .../marvell/octeontx2/nic/otx2_common.c       |   2 +-
 .../net/ethernet/mellanox/mlx5/core/en_main.c |   3 +-
 drivers/net/veth.c                            |  25 +-
 drivers/net/wireless/mediatek/mt76/mac80211.c |   2 +-
 include/net/page_pool/helpers.h               | 219 ++++++++++++++++--
 include/net/page_pool/types.h                 |  38 +--
 net/core/page_pool.c                          |  30 +--
 net/core/skbuff.c                             |   2 +-
 11 files changed, 261 insertions(+), 69 deletions(-)

-- 
2.33.0



^ permalink raw reply	[flat|nested] 2+ messages in thread

* [PATCH net-next v7 3/6] page_pool: remove PP_FLAG_PAGE_FRAG
  2023-08-16 10:01 [PATCH net-next v7 0/6] introduce page_pool_alloc() related API Yunsheng Lin
@ 2023-08-16 10:01 ` Yunsheng Lin
  0 siblings, 0 replies; 2+ messages in thread
From: Yunsheng Lin @ 2023-08-16 10:01 UTC (permalink / raw)
  To: davem, kuba, pabeni
  Cc: netdev, linux-kernel, Yunsheng Lin, Lorenzo Bianconi,
	Alexander Duyck, Liang Chen, Alexander Lobakin, Michael Chan,
	Eric Dumazet, Yisen Zhuang, Salil Mehta, Sunil Goutham,
	Geetha sowjanya, Subbaraya Sundeep, hariprasad, Felix Fietkau,
	Ryder Lee, Shayne Chen, Sean Wang, Kalle Valo, Matthias Brugger,
	AngeloGioacchino Del Regno, Jesper Dangaard Brouer,
	Ilias Apalodimas, linux-wireless, linux-arm-kernel,
	linux-mediatek

PP_FLAG_PAGE_FRAG is not really needed after pp_frag_count
handling is unified and page_pool_alloc_frag() is supported
in 32-bit arch with 64-bit DMA, so remove it.

Signed-off-by: Yunsheng Lin <linyunsheng@huawei.com>
CC: Lorenzo Bianconi <lorenzo@kernel.org>
CC: Alexander Duyck <alexander.duyck@gmail.com>
CC: Liang Chen <liangchen.linux@gmail.com>
CC: Alexander Lobakin <aleksander.lobakin@intel.com>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c                | 2 --
 drivers/net/ethernet/hisilicon/hns3/hns3_enet.c          | 3 +--
 drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c | 2 +-
 drivers/net/wireless/mediatek/mt76/mac80211.c            | 2 +-
 include/net/page_pool/types.h                            | 8 ++------
 net/core/page_pool.c                                     | 3 ---
 net/core/skbuff.c                                        | 2 +-
 7 files changed, 6 insertions(+), 16 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 7be917a8da48..60b699be0d9b 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -3249,8 +3249,6 @@ static int bnxt_alloc_rx_page_pool(struct bnxt *bp,
 	pp.napi = &rxr->bnapi->napi;
 	pp.dev = &bp->pdev->dev;
 	pp.dma_dir = DMA_BIDIRECTIONAL;
-	if (PAGE_SIZE > BNXT_RX_PAGE_SIZE)
-		pp.flags |= PP_FLAG_PAGE_FRAG;
 
 	rxr->page_pool = page_pool_create(&pp);
 	if (IS_ERR(rxr->page_pool)) {
diff --git a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
index eac2d0573241..ff0c219365f1 100644
--- a/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
+++ b/drivers/net/ethernet/hisilicon/hns3/hns3_enet.c
@@ -4926,8 +4926,7 @@ static void hns3_put_ring_config(struct hns3_nic_priv *priv)
 static void hns3_alloc_page_pool(struct hns3_enet_ring *ring)
 {
 	struct page_pool_params pp_params = {
-		.flags = PP_FLAG_DMA_MAP | PP_FLAG_PAGE_FRAG |
-				PP_FLAG_DMA_SYNC_DEV,
+		.flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV,
 		.order = hns3_page_order(ring),
 		.pool_size = ring->desc_num * hns3_buf_size(ring) /
 				(PAGE_SIZE << hns3_page_order(ring)),
diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
index dce3cea00032..edc6acebf369 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c
@@ -1433,7 +1433,7 @@ int otx2_pool_init(struct otx2_nic *pfvf, u16 pool_id,
 		return 0;
 	}
 
-	pp_params.flags = PP_FLAG_PAGE_FRAG | PP_FLAG_DMA_MAP;
+	pp_params.flags = PP_FLAG_DMA_MAP;
 	pp_params.pool_size = numptrs;
 	pp_params.nid = NUMA_NO_NODE;
 	pp_params.dev = pfvf->dev;
diff --git a/drivers/net/wireless/mediatek/mt76/mac80211.c b/drivers/net/wireless/mediatek/mt76/mac80211.c
index d158320bc15d..fe7cc67b7ee2 100644
--- a/drivers/net/wireless/mediatek/mt76/mac80211.c
+++ b/drivers/net/wireless/mediatek/mt76/mac80211.c
@@ -566,7 +566,7 @@ int mt76_create_page_pool(struct mt76_dev *dev, struct mt76_queue *q)
 {
 	struct page_pool_params pp_params = {
 		.order = 0,
-		.flags = PP_FLAG_PAGE_FRAG,
+		.flags = 0,
 		.nid = NUMA_NO_NODE,
 		.dev = dev->dma_dev,
 	};
diff --git a/include/net/page_pool/types.h b/include/net/page_pool/types.h
index 079337c42aa6..4775cf95edb7 100644
--- a/include/net/page_pool/types.h
+++ b/include/net/page_pool/types.h
@@ -15,19 +15,15 @@
  */
 #define PP_FLAG_DMA_SYNC_DEV		BIT(1)
 
-/* for page frag feature */
-#define PP_FLAG_PAGE_FRAG		BIT(2)
-
 /* If set driver will do the page splitting itself. This is used to fail the
  * page_pool creation because there is overlap issue between pp_frag_count and
  * dma_addr_upper in 'struct page' for some arches with
  * PAGE_POOL_DMA_USE_PP_FRAG_COUNT being true.
  */
-#define PP_FLAG_PAGE_SPLIT_IN_DRIVER	BIT(3)
+#define PP_FLAG_PAGE_SPLIT_IN_DRIVER	BIT(2)
 
 #define PP_FLAG_ALL		(PP_FLAG_DMA_MAP |\
 				 PP_FLAG_DMA_SYNC_DEV |\
-				 PP_FLAG_PAGE_FRAG |\
 				 PP_FLAG_PAGE_SPLIT_IN_DRIVER)
 
 /*
@@ -53,7 +49,7 @@ struct pp_alloc_cache {
 
 /**
  * struct page_pool_params - page pool parameters
- * @flags:	PP_FLAG_DMA_MAP, PP_FLAG_DMA_SYNC_DEV, PP_FLAG_PAGE_FRAG,
+ * @flags:	PP_FLAG_DMA_MAP, PP_FLAG_DMA_SYNC_DEV,
  *		PP_FLAG_PAGE_SPLIT_IN_DRIVER
  * @order:	2^order pages on allocation
  * @pool_size:	size of the ptr_ring
diff --git a/net/core/page_pool.c b/net/core/page_pool.c
index 386e6d791e90..d3b8efe98d5e 100644
--- a/net/core/page_pool.c
+++ b/net/core/page_pool.c
@@ -751,9 +751,6 @@ struct page *__page_pool_alloc_frag(struct page_pool *pool,
 	unsigned int max_size = PAGE_SIZE << pool->p.order;
 	struct page *page = pool->frag_page;
 
-	if (WARN_ON(!(pool->p.flags & PP_FLAG_PAGE_FRAG)))
-		return NULL;
-
 	*offset = pool->frag_offset;
 
 	if (page && *offset + size > max_size) {
diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 33fdf04d4334..4b90b6ed10b2 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -5709,7 +5709,7 @@ bool skb_try_coalesce(struct sk_buff *to, struct sk_buff *from,
 	/* In general, avoid mixing page_pool and non-page_pool allocated
 	 * pages within the same SKB. Additionally avoid dealing with clones
 	 * with page_pool pages, in case the SKB is using page_pool fragment
-	 * references (PP_FLAG_PAGE_FRAG). Since we only take full page
+	 * references (page_pool_alloc_frag()). Since we only take full page
 	 * references for cloned SKBs at the moment that would result in
 	 * inconsistent reference counts.
 	 * In theory we could take full references if @from is cloned and
-- 
2.33.0



^ permalink raw reply related	[flat|nested] 2+ messages in thread

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