On Tue, Oct 22, 2024 at 9:25 AM Taehee Yoo <ap420073@xxxxxxxxx> wrote: > > Currently, bnxt_en driver satisfies the requirements of Device memory > TCP, which is tcp-data-split. > So, it implements Device memory TCP for bnxt_en driver. > > From now on, the aggregation ring handles netmem_ref instead of page > regardless of the on/off of netmem. > So, for the aggregation ring, memory will be handled with the netmem > page_pool API instead of generic page_pool API. > > If Devmem is enabled, netmem_ref is used as-is and if Devmem is not > enabled, netmem_ref will be converted to page and that is used. > > Driver recognizes whether the devmem is set or unset based on the > mp_params.mp_priv is not NULL. > Only if devmem is set, it passes PP_FLAG_ALLOW_UNREADABLE_NETMEM. Looks like in the latest version, you pass PP_FLAG_ALLOW_UNREADABLE_NETMEM unconditionally, so this line is obsolete. However, I think you should only pass PP_FLAG_ALLOW_UNREADABLE_NETMEM if hds_thresh==0 and tcp-data-split==1, because otherwise the driver is not configured well enough to handle unreadable netmem, right? I know that we added checks in the devmem binding to detect hds_thresh and tcp-data-split, but we should keep another layer of protection in the driver. The driver should not set PP_FLAG_ALLOW_UNREADABLE_NETMEM unless it's configured to be able to handle unreadable netmem. > > Tested-by: Stanislav Fomichev <sdf@xxxxxxxxxxx> > Signed-off-by: Taehee Yoo <ap420073@xxxxxxxxx> > --- > > v4: > - Do not select NET_DEVMEM in Kconfig. > - Pass PP_FLAG_ALLOW_UNREADABLE_NETMEM flag unconditionally. > - Add __bnxt_rx_agg_pages_xdp(). > - Use gfp flag in __bnxt_alloc_rx_netmem(). > - Do not add *offset in the __bnxt_alloc_rx_netmem(). > - Do not pass queue_idx to bnxt_alloc_rx_page_pool(). > - Add Test tag from Stanislav. > - Add page_pool_recycle_direct_netmem() helper. > > v3: > - Patch added. > > drivers/net/ethernet/broadcom/bnxt/bnxt.c | 182 ++++++++++++++++------ > drivers/net/ethernet/broadcom/bnxt/bnxt.h | 2 +- > include/net/page_pool/helpers.h | 6 + > 3 files changed, 142 insertions(+), 48 deletions(-) > > diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c > index 7d9da483b867..7924b1da0413 100644 > --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c > +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c > @@ -55,6 +55,7 @@ > #include <net/page_pool/helpers.h> > #include <linux/align.h> > #include <net/netdev_queues.h> > +#include <net/netdev_rx_queue.h> > > #include "bnxt_hsi.h" > #include "bnxt.h" > @@ -863,6 +864,22 @@ static void bnxt_tx_int(struct bnxt *bp, struct bnxt_napi *bnapi, int budget) > bnapi->events &= ~BNXT_TX_CMP_EVENT; > } > > +static netmem_ref __bnxt_alloc_rx_netmem(struct bnxt *bp, dma_addr_t *mapping, > + struct bnxt_rx_ring_info *rxr, > + unsigned int *offset, > + gfp_t gfp) > +{ > + netmem_ref netmem; > + > + netmem = page_pool_alloc_netmem(rxr->page_pool, gfp); > + if (!netmem) > + return 0; > + *offset = 0; > + > + *mapping = page_pool_get_dma_addr_netmem(netmem); > + return netmem; > +} > + > static struct page *__bnxt_alloc_rx_page(struct bnxt *bp, dma_addr_t *mapping, > struct bnxt_rx_ring_info *rxr, > unsigned int *offset, > @@ -972,21 +989,21 @@ static inline u16 bnxt_find_next_agg_idx(struct bnxt_rx_ring_info *rxr, u16 idx) > return next; > } > > -static inline int bnxt_alloc_rx_page(struct bnxt *bp, > - struct bnxt_rx_ring_info *rxr, > - u16 prod, gfp_t gfp) > +static inline int bnxt_alloc_rx_netmem(struct bnxt *bp, > + struct bnxt_rx_ring_info *rxr, > + u16 prod, gfp_t gfp) > { > struct rx_bd *rxbd = > &rxr->rx_agg_desc_ring[RX_AGG_RING(bp, prod)][RX_IDX(prod)]; > struct bnxt_sw_rx_agg_bd *rx_agg_buf; > - struct page *page; > - dma_addr_t mapping; > u16 sw_prod = rxr->rx_sw_agg_prod; > unsigned int offset = 0; > + dma_addr_t mapping; > + netmem_ref netmem; > > - page = __bnxt_alloc_rx_page(bp, &mapping, rxr, &offset, gfp); > + netmem = __bnxt_alloc_rx_netmem(bp, &mapping, rxr, &offset, gfp); > > - if (!page) > + if (!netmem) > return -ENOMEM; > > if (unlikely(test_bit(sw_prod, rxr->rx_agg_bmap))) > @@ -996,7 +1013,7 @@ static inline int bnxt_alloc_rx_page(struct bnxt *bp, > rx_agg_buf = &rxr->rx_agg_ring[sw_prod]; > rxr->rx_sw_agg_prod = RING_RX_AGG(bp, NEXT_RX_AGG(sw_prod)); > > - rx_agg_buf->page = page; > + rx_agg_buf->netmem = netmem; > rx_agg_buf->offset = offset; > rx_agg_buf->mapping = mapping; > rxbd->rx_bd_haddr = cpu_to_le64(mapping); > @@ -1044,7 +1061,7 @@ static void bnxt_reuse_rx_agg_bufs(struct bnxt_cp_ring_info *cpr, u16 idx, > struct rx_agg_cmp *agg; > struct bnxt_sw_rx_agg_bd *cons_rx_buf, *prod_rx_buf; > struct rx_bd *prod_bd; > - struct page *page; > + netmem_ref netmem; > > if (p5_tpa) > agg = bnxt_get_tpa_agg_p5(bp, rxr, idx, start + i); > @@ -1061,11 +1078,11 @@ static void bnxt_reuse_rx_agg_bufs(struct bnxt_cp_ring_info *cpr, u16 idx, > cons_rx_buf = &rxr->rx_agg_ring[cons]; > > /* It is possible for sw_prod to be equal to cons, so > - * set cons_rx_buf->page to NULL first. > + * set cons_rx_buf->netmem to 0 first. > */ > - page = cons_rx_buf->page; > - cons_rx_buf->page = NULL; > - prod_rx_buf->page = page; > + netmem = cons_rx_buf->netmem; > + cons_rx_buf->netmem = 0; > + prod_rx_buf->netmem = netmem; > prod_rx_buf->offset = cons_rx_buf->offset; > > prod_rx_buf->mapping = cons_rx_buf->mapping; > @@ -1190,29 +1207,104 @@ static struct sk_buff *bnxt_rx_skb(struct bnxt *bp, > return skb; > } > > -static u32 __bnxt_rx_agg_pages(struct bnxt *bp, > - struct bnxt_cp_ring_info *cpr, > - struct skb_shared_info *shinfo, > - u16 idx, u32 agg_bufs, bool tpa, > - struct xdp_buff *xdp) > +static bool __bnxt_rx_agg_pages_skb(struct bnxt *bp, > + struct bnxt_cp_ring_info *cpr, > + struct sk_buff *skb, > + u16 idx, u32 agg_bufs, bool tpa) > { To be honest I could not immediately understand why __bnxt_rx_agg_pages needed to be split into __bnxt_rx_agg_pages_skb and __bnxt_rx_agg_pages_xdp. Fundamentally speaking we wanted the netmem transition to be as smooth and low-churn as possible for drivers. The only big changes in this patch are the split between skb and xdp. That points to a problem in the design of netmem maybe. For xdp, core makes sure that if xdp is enabled on the device, then the netmem is always pages (never unreadable). So I think netmem should be able to handle xdp as well as skb. Can you give more details on why the split? > struct bnxt_napi *bnapi = cpr->bnapi; > struct pci_dev *pdev = bp->pdev; > - struct bnxt_rx_ring_info *rxr = bnapi->rx_ring; > - u16 prod = rxr->rx_agg_prod; > + struct bnxt_rx_ring_info *rxr; > u32 i, total_frag_len = 0; > bool p5_tpa = false; > + u16 prod; > + > + rxr = bnapi->rx_ring; > + prod = rxr->rx_agg_prod; > > if ((bp->flags & BNXT_FLAG_CHIP_P5_PLUS) && tpa) > p5_tpa = true; > > for (i = 0; i < agg_bufs; i++) { > - skb_frag_t *frag = &shinfo->frags[i]; > - u16 cons, frag_len; > + struct bnxt_sw_rx_agg_bd *cons_rx_buf; > struct rx_agg_cmp *agg; > + u16 cons, frag_len; > + dma_addr_t mapping; > + netmem_ref netmem; > + > + if (p5_tpa) > + agg = bnxt_get_tpa_agg_p5(bp, rxr, idx, i); > + else > + agg = bnxt_get_agg(bp, cpr, idx, i); > + cons = agg->rx_agg_cmp_opaque; > + frag_len = (le32_to_cpu(agg->rx_agg_cmp_len_flags_type) & > + RX_AGG_CMP_LEN) >> RX_AGG_CMP_LEN_SHIFT; > + > + cons_rx_buf = &rxr->rx_agg_ring[cons]; > + skb_add_rx_frag_netmem(skb, i, cons_rx_buf->netmem, > + cons_rx_buf->offset, frag_len, > + BNXT_RX_PAGE_SIZE); > + __clear_bit(cons, rxr->rx_agg_bmap); > + > + /* It is possible for bnxt_alloc_rx_netmem() to allocate > + * a sw_prod index that equals the cons index, so we > + * need to clear the cons entry now. > + */ > + mapping = cons_rx_buf->mapping; > + netmem = cons_rx_buf->netmem; > + cons_rx_buf->netmem = 0; > + > + if (bnxt_alloc_rx_netmem(bp, rxr, prod, GFP_ATOMIC) != 0) { > + skb->len -= frag_len; > + skb->data_len -= frag_len; > + skb->truesize -= BNXT_RX_PAGE_SIZE; > + --skb_shinfo(skb)->nr_frags; > + cons_rx_buf->netmem = netmem; > + > + /* Update prod since possibly some pages have been > + * allocated already. > + */ > + rxr->rx_agg_prod = prod; > + bnxt_reuse_rx_agg_bufs(cpr, idx, i, agg_bufs - i, tpa); > + return 0; > + } > + > + dma_sync_single_for_cpu(&pdev->dev, mapping, BNXT_RX_PAGE_SIZE, > + bp->rx_dir); > + You should probably use page_pool_dma_sync_for_cpu. I'm merging a change to make that function skip dma-syncing for net_iov: https://lore.kernel.org/netdev/20241029204541.1301203-5-almasrymina@xxxxxxxxxx/ Which is necessary following Jason Gunthorpe's guidance. > + total_frag_len += frag_len; > + prod = NEXT_RX_AGG(prod); > + } > + rxr->rx_agg_prod = prod; > + return total_frag_len; > +} > + > +static u32 __bnxt_rx_agg_pages_xdp(struct bnxt *bp, > + struct bnxt_cp_ring_info *cpr, > + struct skb_shared_info *shinfo, > + u16 idx, u32 agg_bufs, bool tpa, > + struct xdp_buff *xdp) > +{ > + struct bnxt_napi *bnapi = cpr->bnapi; > + struct pci_dev *pdev = bp->pdev; > + struct bnxt_rx_ring_info *rxr; > + u32 i, total_frag_len = 0; > + bool p5_tpa = false; > + u16 prod; > + > + rxr = bnapi->rx_ring; > + prod = rxr->rx_agg_prod; > + > + if ((bp->flags & BNXT_FLAG_CHIP_P5_PLUS) && tpa) > + p5_tpa = true; > + > + for (i = 0; i < agg_bufs; i++) { > struct bnxt_sw_rx_agg_bd *cons_rx_buf; > - struct page *page; > + skb_frag_t *frag = &shinfo->frags[i]; > + struct rx_agg_cmp *agg; > + u16 cons, frag_len; > dma_addr_t mapping; > + netmem_ref netmem; > > if (p5_tpa) > agg = bnxt_get_tpa_agg_p5(bp, rxr, idx, i); > @@ -1223,9 +1315,10 @@ static u32 __bnxt_rx_agg_pages(struct bnxt *bp, > RX_AGG_CMP_LEN) >> RX_AGG_CMP_LEN_SHIFT; > > cons_rx_buf = &rxr->rx_agg_ring[cons]; > - skb_frag_fill_page_desc(frag, cons_rx_buf->page, > - cons_rx_buf->offset, frag_len); > + skb_frag_fill_netmem_desc(frag, cons_rx_buf->netmem, > + cons_rx_buf->offset, frag_len); > shinfo->nr_frags = i + 1; > + > __clear_bit(cons, rxr->rx_agg_bmap); > > /* It is possible for bnxt_alloc_rx_page() to allocate > @@ -1233,15 +1326,15 @@ static u32 __bnxt_rx_agg_pages(struct bnxt *bp, > * need to clear the cons entry now. > */ > mapping = cons_rx_buf->mapping; > - page = cons_rx_buf->page; > - cons_rx_buf->page = NULL; > + netmem = cons_rx_buf->netmem; > + cons_rx_buf->netmem = 0; > > - if (xdp && page_is_pfmemalloc(page)) > + if (netmem_is_pfmemalloc(netmem)) > xdp_buff_set_frag_pfmemalloc(xdp); > > - if (bnxt_alloc_rx_page(bp, rxr, prod, GFP_ATOMIC) != 0) { > + if (bnxt_alloc_rx_netmem(bp, rxr, prod, GFP_ATOMIC) != 0) { > --shinfo->nr_frags; > - cons_rx_buf->page = page; > + cons_rx_buf->netmem = netmem; > > /* Update prod since possibly some pages have been > * allocated already. > @@ -1266,20 +1359,12 @@ static struct sk_buff *bnxt_rx_agg_pages_skb(struct bnxt *bp, > struct sk_buff *skb, u16 idx, > u32 agg_bufs, bool tpa) > { > - struct skb_shared_info *shinfo = skb_shinfo(skb); > - u32 total_frag_len = 0; > - > - total_frag_len = __bnxt_rx_agg_pages(bp, cpr, shinfo, idx, > - agg_bufs, tpa, NULL); > - if (!total_frag_len) { > + if (!__bnxt_rx_agg_pages_skb(bp, cpr, skb, idx, agg_bufs, tpa)) { > skb_mark_for_recycle(skb); > dev_kfree_skb(skb); > return NULL; > } > > - skb->data_len += total_frag_len; > - skb->len += total_frag_len; > - skb->truesize += BNXT_RX_PAGE_SIZE * agg_bufs; > return skb; > } > > @@ -1294,8 +1379,8 @@ static u32 bnxt_rx_agg_pages_xdp(struct bnxt *bp, > if (!xdp_buff_has_frags(xdp)) > shinfo->nr_frags = 0; > > - total_frag_len = __bnxt_rx_agg_pages(bp, cpr, shinfo, > - idx, agg_bufs, tpa, xdp); > + total_frag_len = __bnxt_rx_agg_pages_xdp(bp, cpr, shinfo, > + idx, agg_bufs, tpa, xdp); > if (total_frag_len) { > xdp_buff_set_frags_flag(xdp); > shinfo->nr_frags = agg_bufs; > @@ -3341,15 +3426,15 @@ static void bnxt_free_one_rx_agg_ring(struct bnxt *bp, struct bnxt_rx_ring_info > > for (i = 0; i < max_idx; i++) { > struct bnxt_sw_rx_agg_bd *rx_agg_buf = &rxr->rx_agg_ring[i]; > - struct page *page = rx_agg_buf->page; > + netmem_ref netmem = rx_agg_buf->netmem; > > - if (!page) > + if (!netmem) > continue; > > - rx_agg_buf->page = NULL; > + rx_agg_buf->netmem = 0; > __clear_bit(i, rxr->rx_agg_bmap); > > - page_pool_recycle_direct(rxr->page_pool, page); > + page_pool_recycle_direct_netmem(rxr->page_pool, netmem); > } > } > > @@ -3620,7 +3705,10 @@ static int bnxt_alloc_rx_page_pool(struct bnxt *bp, > pp.dev = &bp->pdev->dev; > pp.dma_dir = bp->rx_dir; > pp.max_len = PAGE_SIZE; > - pp.flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV; > + pp.flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV | > + PP_FLAG_ALLOW_UNREADABLE_NETMEM; PP_FLAG_ALLOW_UNREADABLE_NETMEM should only be set when the driver can handle unreadable netmem. I.e. when hds_thresh==0 and tcp-data-split==1. -- Thanks, Mina