[PATCH V3,net-next] net: mana: Add page pool for RX buffers

Haiyang Zhang
2023-07-21T19:05:37Z

Add page pool for RX buffers for faster buffer cycle and reduce CPU
usage.

The standard page pool API is used.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
---
V3:
Update xdp mem model, pool param, alloc as suggested by Jakub Kicinski
V2:
Use the standard page pool API as suggested by Jesper Dangaard Brouer

---
drivers/net/ethernet/microsoft/mana/mana_en.c | 91 +++++++++++++++----
include/net/mana/mana.h | 3 +
2 files changed, 78 insertions(+), 16 deletions(-)

diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index a499e460594b..4307f25f8c7a 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -1414,8 +1414,8 @@ static struct sk_buff *mana_build_skb(struct mana_rxq *rxq, void *buf_va,
return skb;
}

-static void mana_rx_skb(void *buf_va, struct mana_rxcomp_oob *cqe,
- struct mana_rxq *rxq)
+static void mana_rx_skb(void *buf_va, bool from_pool,
+ struct mana_rxcomp_oob *cqe, struct mana_rxq *rxq)
{
struct mana_stats_rx *rx_stats = &rxq->stats;
struct net_device *ndev = rxq->ndev;
@@ -1448,6 +1448,9 @@ static void mana_rx_skb(void *buf_va, struct mana_rxcomp_oob *cqe,
if (!skb)
goto drop;

+ if (from_pool)
+ skb_mark_for_recycle(skb);
+
skb->dev = napi->dev;

skb->protocol = eth_type_trans(skb, ndev);
@@ -1498,9 +1501,14 @@ static void mana_rx_skb(void *buf_va, struct mana_rxcomp_oob *cqe,
u64_stats_update_end(&rx_stats->syncp);

drop:
- WARN_ON_ONCE(rxq->xdp_save_va);
- /* Save for reuse */
- rxq->xdp_save_va = buf_va;
+ if (from_pool) {
+ page_pool_recycle_direct(rxq->page_pool,
+ virt_to_head_page(buf_va));
+ } else {
+ WARN_ON_ONCE(rxq->xdp_save_va);
+ /* Save for reuse */
+ rxq->xdp_save_va = buf_va;
+ }

++ndev->stats.rx_dropped;

@@ -1508,11 +1516,13 @@ static void mana_rx_skb(void *buf_va, struct mana_rxcomp_oob *cqe,
}

static void *mana_get_rxfrag(struct mana_rxq *rxq, struct device *dev,
- dma_addr_t *da, bool is_napi)
+ dma_addr_t *da, bool *from_pool, bool is_napi)
{
struct page *page;
void *va;

+ *from_pool = false;
+
/* Reuse XDP dropped page if available */
if (rxq->xdp_save_va) {
va = rxq->xdp_save_va;
@@ -1533,17 +1543,22 @@ static void *mana_get_rxfrag(struct mana_rxq *rxq, struct device *dev,
return NULL;
}
} else {
- page = dev_alloc_page();
+ page = page_pool_dev_alloc_pages(rxq->page_pool);
if (!page)
return NULL;

+ *from_pool = true;
va = page_to_virt(page);
}

*da = dma_map_single(dev, va + rxq->headroom, rxq->datasize,
DMA_FROM_DEVICE);
if (dma_mapping_error(dev, *da)) {
- put_page(virt_to_head_page(va));
+ if (*from_pool)
+ page_pool_put_full_page(rxq->page_pool, page, is_napi);
+ else
+ put_page(virt_to_head_page(va));
+
return NULL;
}

@@ -1552,21 +1567,25 @@ static void *mana_get_rxfrag(struct mana_rxq *rxq, struct device *dev,

/* Allocate frag for rx buffer, and save the old buf */
static void mana_refill_rx_oob(struct device *dev, struct mana_rxq *rxq,
- struct mana_recv_buf_oob *rxoob, void **old_buf)
+ struct mana_recv_buf_oob *rxoob, void **old_buf,
+ bool *old_fp)
{
+ bool from_pool;
dma_addr_t da;
void *va;

- va = mana_get_rxfrag(rxq, dev, &da, true);
+ va = mana_get_rxfrag(rxq, dev, &da, &from_pool, true);
if (!va)
return;

dma_unmap_single(dev, rxoob->sgl[0].address, rxq->datasize,
DMA_FROM_DEVICE);
*old_buf = rxoob->buf_va;
+ *old_fp = rxoob->from_pool;

rxoob->buf_va = va;
rxoob->sgl[0].address = da;
+ rxoob->from_pool = from_pool;
}

static void mana_process_rx_cqe(struct mana_rxq *rxq, struct mana_cq *cq,
@@ -1580,6 +1599,7 @@ static void mana_process_rx_cqe(struct mana_rxq *rxq, struct mana_cq *cq,
struct device *dev = gc->dev;
void *old_buf = NULL;
u32 curr, pktlen;
+ bool old_fp;

apc = netdev_priv(ndev);

@@ -1622,12 +1642,12 @@ static void mana_process_rx_cqe(struct mana_rxq *rxq, struct mana_cq *cq,
rxbuf_oob = &rxq->rx_oobs[curr];
WARN_ON_ONCE(rxbuf_oob->wqe_inf.wqe_size_in_bu != 1);

- mana_refill_rx_oob(dev, rxq, rxbuf_oob, &old_buf);
+ mana_refill_rx_oob(dev, rxq, rxbuf_oob, &old_buf, &old_fp);

/* Unsuccessful refill will have old_buf == NULL.
* In this case, mana_rx_skb() will drop the packet.
*/
- mana_rx_skb(old_buf, oob, rxq);
+ mana_rx_skb(old_buf, old_fp, oob, rxq);

drop:
mana_move_wq_tail(rxq->gdma_rq, rxbuf_oob->wqe_inf.wqe_size_in_bu);
@@ -1659,6 +1679,8 @@ static void mana_poll_rx_cq(struct mana_cq *cq)

if (rxq->xdp_flush)
xdp_do_flush();
+
+ page_pool_nid_changed(rxq->page_pool, numa_mem_id());
}

static int mana_cq_handler(void *context, struct gdma_queue *gdma_queue)
@@ -1881,6 +1903,7 @@ static void mana_destroy_rxq(struct mana_port_context *apc,
struct mana_recv_buf_oob *rx_oob;
struct device *dev = gc->dev;
struct napi_struct *napi;
+ struct page *page;
int i;

if (!rxq)
@@ -1913,10 +1936,18 @@ static void mana_destroy_rxq(struct mana_port_context *apc,
dma_unmap_single(dev, rx_oob->sgl[0].address,
rx_oob->sgl[0].size, DMA_FROM_DEVICE);

- put_page(virt_to_head_page(rx_oob->buf_va));
+ page = virt_to_head_page(rx_oob->buf_va);
+
+ if (rx_oob->from_pool)
+ page_pool_put_full_page(rxq->page_pool, page, false);
+ else
+ put_page(page);
+
rx_oob->buf_va = NULL;
}

+ page_pool_destroy(rxq->page_pool);
+
if (rxq->gdma_rq)
mana_gd_destroy_queue(gc, rxq->gdma_rq);

@@ -1927,18 +1958,20 @@ static int mana_fill_rx_oob(struct mana_recv_buf_oob *rx_oob, u32 mem_key,
struct mana_rxq *rxq, struct device *dev)
{
struct mana_port_context *mpc = netdev_priv(rxq->ndev);
+ bool from_pool = false;
dma_addr_t da;
void *va;

if (mpc->rxbufs_pre)
va = mana_get_rxbuf_pre(rxq, &da);
else
- va = mana_get_rxfrag(rxq, dev, &da, false);
+ va = mana_get_rxfrag(rxq, dev, &da, &from_pool, false);

if (!va)
return -ENOMEM;

rx_oob->buf_va = va;
+ rx_oob->from_pool = from_pool;

rx_oob->sgl[0].address = da;
rx_oob->sgl[0].size = rxq->datasize;
@@ -2008,6 +2041,25 @@ static int mana_push_wqe(struct mana_rxq *rxq)
return 0;
}

+static int mana_create_page_pool(struct mana_rxq *rxq)
+{
+ struct page_pool_params pprm = {};
+ int ret;
+
+ pprm.pool_size = RX_BUFFERS_PER_QUEUE;
+ pprm.napi = &rxq->rx_cq.napi;
+
+ rxq->page_pool = page_pool_create(&pprm);
+
+ if (IS_ERR(rxq->page_pool)) {
+ ret = PTR_ERR(rxq->page_pool);
+ rxq->page_pool = NULL;
+ return ret;
+ }
+
+ return 0;
+}
+
static struct mana_rxq *mana_create_rxq(struct mana_port_context *apc,
u32 rxq_idx, struct mana_eq *eq,
struct net_device *ndev)
@@ -2037,6 +2089,13 @@ static struct mana_rxq *mana_create_rxq(struct mana_port_context *apc,
mana_get_rxbuf_cfg(ndev->mtu, &rxq->datasize, &rxq->alloc_size,
&rxq->headroom);

+ /* Create page pool for RX queue */
+ err = mana_create_page_pool(rxq);
+ if (err) {
+ netdev_err(ndev, "Create page pool err:%d\n", err);
+ goto out;
+ }
+
err = mana_alloc_rx_wqe(apc, rxq, &rq_size, &cq_size);
if (err)
goto out;
@@ -2108,8 +2167,8 @@ static struct mana_rxq *mana_create_rxq(struct mana_port_context *apc,

WARN_ON(xdp_rxq_info_reg(&rxq->xdp_rxq, ndev, rxq_idx,
cq->napi.napi_id));
- WARN_ON(xdp_rxq_info_reg_mem_model(&rxq->xdp_rxq,
- MEM_TYPE_PAGE_SHARED, NULL));
+ WARN_ON(xdp_rxq_info_reg_mem_model(&rxq->xdp_rxq, MEM_TYPE_PAGE_POOL,
+ rxq->page_pool));

napi_enable(&cq->napi);

diff --git a/include/net/mana/mana.h b/include/net/mana/mana.h
index 024ad8ddb27e..b12859511839 100644
--- a/include/net/mana/mana.h
+++ b/include/net/mana/mana.h
@@ -280,6 +280,7 @@ struct mana_recv_buf_oob {
struct gdma_wqe_request wqe_req;

void *buf_va;
+ bool from_pool; /* allocated from a page pool */

/* SGL of the buffer going to be sent has part of the work request. */
u32 num_sge;
@@ -330,6 +331,8 @@ struct mana_rxq {
bool xdp_flush;
int xdp_rc; /* XDP redirect return code */

+ struct page_pool *page_pool;
+
/* MUST BE THE LAST MEMBER:
* Each receive buffer has an associated mana_recv_buf_oob.
*/
--
2.25.1