From 51151a16a60f0a886a0b1e4a0697001198af50c4 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Sun, 23 Jun 2013 08:17:56 -0700 Subject: [PATCH] mlx4: allow order-0 memory allocations in RX path Signed-off-by: Eric Dumazet mlx4 exclusively uses order-2 allocations in RX path, which are likely to fail under memory pressure. We therefore drop frames more than needed. This patch tries order-3, order-2, order-1 and finally order-0 allocations to keep good performance, yet allow allocations if/when memory gets fragmented. By using larger pages, and avoiding unnecessary get_page()/put_page() on compound pages, this patch improves performance as well, lowering false sharing on struct page. Also use GFP_KERNEL allocations in initialization path, as allocating 12 MB (390 order-3 pages) can easily fail with GFP_ATOMIC. Signed-off-by: Eric Dumazet Cc: Amir Vadai Acked-by: Or Gerlitz Signed-off-by: David S. Miller --- drivers/net/ethernet/mellanox/mlx4/en_rx.c | 169 ++++++++++--------- drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 12 +- 2 files changed, 95 insertions(+), 86 deletions(-) diff --git a/drivers/net/ethernet/mellanox/mlx4/en_rx.c b/drivers/net/ethernet/mellanox/mlx4/en_rx.c index 9c57581b021c..76997b93fdfe 100644 --- a/drivers/net/ethernet/mellanox/mlx4/en_rx.c +++ b/drivers/net/ethernet/mellanox/mlx4/en_rx.c @@ -43,40 +43,64 @@ #include "mlx4_en.h" +static int mlx4_alloc_pages(struct mlx4_en_priv *priv, + struct mlx4_en_rx_alloc *page_alloc, + const struct mlx4_en_frag_info *frag_info, + gfp_t _gfp) +{ + int order; + struct page *page; + dma_addr_t dma; + + for (order = MLX4_EN_ALLOC_PREFER_ORDER; ;) { + gfp_t gfp = _gfp; + + if (order) + gfp |= __GFP_COMP | __GFP_NOWARN; + page = alloc_pages(gfp, order); + if (likely(page)) + break; + if (--order < 0 || + ((PAGE_SIZE << order) < frag_info->frag_size)) + return -ENOMEM; + } + dma = dma_map_page(priv->ddev, page, 0, PAGE_SIZE << order, + PCI_DMA_FROMDEVICE); + if (dma_mapping_error(priv->ddev, dma)) { + put_page(page); + return -ENOMEM; + } + page_alloc->size = PAGE_SIZE << order; + page_alloc->page = page; + page_alloc->dma = dma; + page_alloc->offset = frag_info->frag_align; + /* Not doing get_page() for each frag is a big win + * on asymetric workloads. + */ + atomic_set(&page->_count, page_alloc->size / frag_info->frag_stride); + return 0; +} + static int mlx4_en_alloc_frags(struct mlx4_en_priv *priv, struct mlx4_en_rx_desc *rx_desc, struct mlx4_en_rx_alloc *frags, - struct mlx4_en_rx_alloc *ring_alloc) + struct mlx4_en_rx_alloc *ring_alloc, + gfp_t gfp) { struct mlx4_en_rx_alloc page_alloc[MLX4_EN_MAX_RX_FRAGS]; - struct mlx4_en_frag_info *frag_info; + const struct mlx4_en_frag_info *frag_info; struct page *page; dma_addr_t dma; int i; for (i = 0; i < priv->num_frags; i++) { frag_info = &priv->frag_info[i]; - if (ring_alloc[i].offset == frag_info->last_offset) { - page = alloc_pages(GFP_ATOMIC | __GFP_COMP, - MLX4_EN_ALLOC_ORDER); - if (!page) - goto out; - dma = dma_map_page(priv->ddev, page, 0, - MLX4_EN_ALLOC_SIZE, PCI_DMA_FROMDEVICE); - if (dma_mapping_error(priv->ddev, dma)) { - put_page(page); - goto out; - } - page_alloc[i].page = page; - page_alloc[i].dma = dma; - page_alloc[i].offset = frag_info->frag_align; - } else { - page_alloc[i].page = ring_alloc[i].page; - get_page(ring_alloc[i].page); - page_alloc[i].dma = ring_alloc[i].dma; - page_alloc[i].offset = ring_alloc[i].offset + - frag_info->frag_stride; - } + page_alloc[i] = ring_alloc[i]; + page_alloc[i].offset += frag_info->frag_stride; + if (page_alloc[i].offset + frag_info->frag_stride <= ring_alloc[i].size) + continue; + if (mlx4_alloc_pages(priv, &page_alloc[i], frag_info, gfp)) + goto out; } for (i = 0; i < priv->num_frags; i++) { @@ -88,14 +112,16 @@ static int mlx4_en_alloc_frags(struct mlx4_en_priv *priv, return 0; - out: while (i--) { frag_info = &priv->frag_info[i]; - if (ring_alloc[i].offset == frag_info->last_offset) + if (page_alloc[i].page != ring_alloc[i].page) { dma_unmap_page(priv->ddev, page_alloc[i].dma, - MLX4_EN_ALLOC_SIZE, PCI_DMA_FROMDEVICE); - put_page(page_alloc[i].page); + page_alloc[i].size, PCI_DMA_FROMDEVICE); + page = page_alloc[i].page; + atomic_set(&page->_count, 1); + put_page(page); + } } return -ENOMEM; } @@ -104,12 +130,12 @@ static void mlx4_en_free_frag(struct mlx4_en_priv *priv, struct mlx4_en_rx_alloc *frags, int i) { - struct mlx4_en_frag_info *frag_info = &priv->frag_info[i]; + const struct mlx4_en_frag_info *frag_info = &priv->frag_info[i]; - if (frags[i].offset == frag_info->last_offset) { - dma_unmap_page(priv->ddev, frags[i].dma, MLX4_EN_ALLOC_SIZE, + if (frags[i].offset + frag_info->frag_stride > frags[i].size) + dma_unmap_page(priv->ddev, frags[i].dma, frags[i].size, PCI_DMA_FROMDEVICE); - } + if (frags[i].page) put_page(frags[i].page); } @@ -117,35 +143,28 @@ static void mlx4_en_free_frag(struct mlx4_en_priv *priv, static int mlx4_en_init_allocator(struct mlx4_en_priv *priv, struct mlx4_en_rx_ring *ring) { - struct mlx4_en_rx_alloc *page_alloc; int i; + struct mlx4_en_rx_alloc *page_alloc; for (i = 0; i < priv->num_frags; i++) { - page_alloc = &ring->page_alloc[i]; - page_alloc->page = alloc_pages(GFP_ATOMIC | __GFP_COMP, - MLX4_EN_ALLOC_ORDER); - if (!page_alloc->page) - goto out; + const struct mlx4_en_frag_info *frag_info = &priv->frag_info[i]; - page_alloc->dma = dma_map_page(priv->ddev, page_alloc->page, 0, - MLX4_EN_ALLOC_SIZE, PCI_DMA_FROMDEVICE); - if (dma_mapping_error(priv->ddev, page_alloc->dma)) { - put_page(page_alloc->page); - page_alloc->page = NULL; + if (mlx4_alloc_pages(priv, &ring->page_alloc[i], + frag_info, GFP_KERNEL)) goto out; - } - page_alloc->offset = priv->frag_info[i].frag_align; - en_dbg(DRV, priv, "Initialized allocator:%d with page:%p\n", - i, page_alloc->page); } return 0; out: while (i--) { + struct page *page; + page_alloc = &ring->page_alloc[i]; dma_unmap_page(priv->ddev, page_alloc->dma, - MLX4_EN_ALLOC_SIZE, PCI_DMA_FROMDEVICE); - put_page(page_alloc->page); + page_alloc->size, PCI_DMA_FROMDEVICE); + page = page_alloc->page; + atomic_set(&page->_count, 1); + put_page(page); page_alloc->page = NULL; } return -ENOMEM; @@ -158,13 +177,18 @@ static void mlx4_en_destroy_allocator(struct mlx4_en_priv *priv, int i; for (i = 0; i < priv->num_frags; i++) { + const struct mlx4_en_frag_info *frag_info = &priv->frag_info[i]; + page_alloc = &ring->page_alloc[i]; en_dbg(DRV, priv, "Freeing allocator:%d count:%d\n", i, page_count(page_alloc->page)); dma_unmap_page(priv->ddev, page_alloc->dma, - MLX4_EN_ALLOC_SIZE, PCI_DMA_FROMDEVICE); - put_page(page_alloc->page); + page_alloc->size, PCI_DMA_FROMDEVICE); + while (page_alloc->offset + frag_info->frag_stride < page_alloc->size) { + put_page(page_alloc->page); + page_alloc->offset += frag_info->frag_stride; + } page_alloc->page = NULL; } } @@ -195,13 +219,14 @@ static void mlx4_en_init_rx_desc(struct mlx4_en_priv *priv, } static int mlx4_en_prepare_rx_desc(struct mlx4_en_priv *priv, - struct mlx4_en_rx_ring *ring, int index) + struct mlx4_en_rx_ring *ring, int index, + gfp_t gfp) { struct mlx4_en_rx_desc *rx_desc = ring->buf + (index * ring->stride); struct mlx4_en_rx_alloc *frags = ring->rx_info + (index << priv->log_rx_info); - return mlx4_en_alloc_frags(priv, rx_desc, frags, ring->page_alloc); + return mlx4_en_alloc_frags(priv, rx_desc, frags, ring->page_alloc, gfp); } static inline void mlx4_en_update_rx_prod_db(struct mlx4_en_rx_ring *ring) @@ -235,7 +260,8 @@ static int mlx4_en_fill_rx_buffers(struct mlx4_en_priv *priv) ring = &priv->rx_ring[ring_ind]; if (mlx4_en_prepare_rx_desc(priv, ring, - ring->actual_size)) { + ring->actual_size, + GFP_KERNEL)) { if (ring->actual_size < MLX4_EN_MIN_RX_SIZE) { en_err(priv, "Failed to allocate " "enough rx buffers\n"); @@ -450,11 +476,11 @@ static int mlx4_en_complete_rx_desc(struct mlx4_en_priv *priv, DMA_FROM_DEVICE); /* Save page reference in skb */ - get_page(frags[nr].page); __skb_frag_set_page(&skb_frags_rx[nr], frags[nr].page); skb_frag_size_set(&skb_frags_rx[nr], frag_info->frag_size); skb_frags_rx[nr].page_offset = frags[nr].offset; skb->truesize += frag_info->frag_stride; + frags[nr].page = NULL; } /* Adjust size of last fragment to match actual length */ if (nr > 0) @@ -547,7 +573,7 @@ static void mlx4_en_refill_rx_buffers(struct mlx4_en_priv *priv, int index = ring->prod & ring->size_mask; while ((u32) (ring->prod - ring->cons) < ring->actual_size) { - if (mlx4_en_prepare_rx_desc(priv, ring, index)) + if (mlx4_en_prepare_rx_desc(priv, ring, index, GFP_ATOMIC)) break; ring->prod++; index = ring->prod & ring->size_mask; @@ -805,21 +831,7 @@ int mlx4_en_poll_rx_cq(struct napi_struct *napi, int budget) return done; } - -/* Calculate the last offset position that accommodates a full fragment - * (assuming fagment size = stride-align) */ -static int mlx4_en_last_alloc_offset(struct mlx4_en_priv *priv, u16 stride, u16 align) -{ - u16 res = MLX4_EN_ALLOC_SIZE % stride; - u16 offset = MLX4_EN_ALLOC_SIZE - stride - res + align; - - en_dbg(DRV, priv, "Calculated last offset for stride:%d align:%d " - "res:%d offset:%d\n", stride, align, res, offset); - return offset; -} - - -static int frag_sizes[] = { +static const int frag_sizes[] = { FRAG_SZ0, FRAG_SZ1, FRAG_SZ2, @@ -847,9 +859,6 @@ void mlx4_en_calc_rx_buf(struct net_device *dev) priv->frag_info[i].frag_stride = ALIGN(frag_sizes[i], SMP_CACHE_BYTES); } - priv->frag_info[i].last_offset = mlx4_en_last_alloc_offset( - priv, priv->frag_info[i].frag_stride, - priv->frag_info[i].frag_align); buf_size += priv->frag_info[i].frag_size; i++; } @@ -861,13 +870,13 @@ void mlx4_en_calc_rx_buf(struct net_device *dev) en_dbg(DRV, priv, "Rx buffer scatter-list (effective-mtu:%d " "num_frags:%d):\n", eff_mtu, priv->num_frags); for (i = 0; i < priv->num_frags; i++) { - en_dbg(DRV, priv, " frag:%d - size:%d prefix:%d align:%d " - "stride:%d last_offset:%d\n", i, - priv->frag_info[i].frag_size, - priv->frag_info[i].frag_prefix_size, - priv->frag_info[i].frag_align, - priv->frag_info[i].frag_stride, - priv->frag_info[i].last_offset); + en_err(priv, + " frag:%d - size:%d prefix:%d align:%d stride:%d\n", + i, + priv->frag_info[i].frag_size, + priv->frag_info[i].frag_prefix_size, + priv->frag_info[i].frag_align, + priv->frag_info[i].frag_stride); } } diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h index 57192a8f1d5e..35fb60e2320c 100644 --- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h +++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h @@ -96,7 +96,8 @@ /* Use the maximum between 16384 and a single page */ #define MLX4_EN_ALLOC_SIZE PAGE_ALIGN(16384) -#define MLX4_EN_ALLOC_ORDER get_order(MLX4_EN_ALLOC_SIZE) + +#define MLX4_EN_ALLOC_PREFER_ORDER PAGE_ALLOC_COSTLY_ORDER /* Receive fragment sizes; we use at most 3 fragments (for 9600 byte MTU * and 4K allocations) */ @@ -234,9 +235,10 @@ struct mlx4_en_tx_desc { #define MLX4_EN_CX3_HIGH_ID 0x1005 struct mlx4_en_rx_alloc { - struct page *page; - dma_addr_t dma; - u16 offset; + struct page *page; + dma_addr_t dma; + u32 offset; + u32 size; }; struct mlx4_en_tx_ring { @@ -439,8 +441,6 @@ struct mlx4_en_frag_info { u16 frag_prefix_size; u16 frag_stride; u16 frag_align; - u16 last_offset; - }; #ifdef CONFIG_MLX4_EN_DCB -- 2.20.1