[SRU][J:linux-azure][PATCH 2/2] Revert "net: mana: Use page pool fragments for RX buffers instead of full pages to improve memory efficiency."
John Cabaj
john.cabaj at canonical.com
Tue Nov 18 22:24:00 UTC 2025
BugLink: https://bugs.launchpad.net/bugs/2131828
This reverts commit 5b59c72c34192a8dca843a68c5d82c4cfae2bc03.
Signed-off-by: John Cabaj <john.cabaj at canonical.com>
---
.../net/ethernet/microsoft/mana/mana_bpf.c | 46 +-----
drivers/net/ethernet/microsoft/mana/mana_en.c | 150 ++++++------------
include/net/mana/mana.h | 4 -
3 files changed, 51 insertions(+), 149 deletions(-)
diff --git a/drivers/net/ethernet/microsoft/mana/mana_bpf.c b/drivers/net/ethernet/microsoft/mana/mana_bpf.c
index 426852939338c..23b1521c0df96 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_bpf.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_bpf.c
@@ -174,7 +174,6 @@ static int mana_xdp_set(struct net_device *ndev, struct bpf_prog *prog,
struct mana_port_context *apc = netdev_priv(ndev);
struct bpf_prog *old_prog;
struct gdma_context *gc;
- int err;
gc = apc->ac->gdma_dev->gdma_context;
@@ -196,57 +195,18 @@ static int mana_xdp_set(struct net_device *ndev, struct bpf_prog *prog,
*/
apc->bpf_prog = prog;
- if (apc->port_is_up) {
- /* Re-create rxq's after xdp prog was loaded or unloaded.
- * Ex: re create rxq's to switch from full pages to smaller
- * size page fragments when xdp prog is unloaded and
- * vice-versa.
- */
-
- /* Pre-allocate buffers to prevent failure in mana_attach */
- err = mana_pre_alloc_rxbufs(apc, ndev->mtu, apc->num_queues);
- if (err) {
- NL_SET_ERR_MSG_MOD(extack,
- "XDP: Insufficient memory for tx/rx re-config");
- return err;
- }
-
- err = mana_detach(ndev, false);
- if (err) {
- netdev_err(ndev,
- "mana_detach failed at xdp set: %d\n", err);
- NL_SET_ERR_MSG_MOD(extack,
- "XDP: Re-config failed at detach");
- goto err_dealloc_rxbuffs;
- }
-
- err = mana_attach(ndev);
- if (err) {
- netdev_err(ndev,
- "mana_attach failed at xdp set: %d\n", err);
- NL_SET_ERR_MSG_MOD(extack,
- "XDP: Re-config failed at attach");
- goto err_dealloc_rxbuffs;
- }
-
- mana_chn_setxdp(apc, prog);
- mana_pre_dealloc_rxbufs(apc);
- }
-
if (old_prog)
bpf_prog_put(old_prog);
+ if (apc->port_is_up)
+ mana_chn_setxdp(apc, prog);
+
if (prog)
ndev->max_mtu = MANA_XDP_MTU_MAX;
else
ndev->max_mtu = gc->adapter_mtu - ETH_HLEN;
return 0;
-
-err_dealloc_rxbuffs:
- apc->bpf_prog = old_prog;
- mana_pre_dealloc_rxbufs(apc);
- return err;
}
int mana_bpf(struct net_device *ndev, struct netdev_bpf *bpf)
diff --git a/drivers/net/ethernet/microsoft/mana/mana_en.c b/drivers/net/ethernet/microsoft/mana/mana_en.c
index 671e3253180ad..87eff5062c8fa 100644
--- a/drivers/net/ethernet/microsoft/mana/mana_en.c
+++ b/drivers/net/ethernet/microsoft/mana/mana_en.c
@@ -44,15 +44,6 @@ static const struct file_operations mana_dbg_q_fops = {
.read = mana_dbg_q_read,
};
-static void mana_put_rx_page(struct mana_rxq *rxq, struct page *page,
- bool from_pool)
-{
- if (from_pool)
- page_pool_put_full_page(rxq->page_pool, page, false);
- else
- put_page(page);
-}
-
/* Microsoft Azure Network Adapter (MANA) functions */
static int mana_open(struct net_device *ndev)
@@ -623,40 +614,21 @@ static void *mana_get_rxbuf_pre(struct mana_rxq *rxq, dma_addr_t *da)
}
/* Get RX buffer's data size, alloc size, XDP headroom based on MTU */
-static void mana_get_rxbuf_cfg(struct mana_port_context *apc,
- int mtu, u32 *datasize, u32 *alloc_size,
- u32 *headroom, u32 *frag_count)
+static void mana_get_rxbuf_cfg(int mtu, u32 *datasize, u32 *alloc_size,
+ u32 *headroom)
{
- u32 len, buf_size;
-
- /* Calculate datasize first (consistent across all cases) */
- *datasize = mtu + ETH_HLEN;
-
- /* For xdp and jumbo frames make sure only one packet fits per page */
- if (mtu + MANA_RXBUF_PAD > PAGE_SIZE / 2 || mana_xdp_get(apc)) {
- if (mana_xdp_get(apc)) {
- *headroom = XDP_PACKET_HEADROOM;
- *alloc_size = PAGE_SIZE;
- } else {
- *headroom = 0; /* no support for XDP */
- *alloc_size = SKB_DATA_ALIGN(mtu + MANA_RXBUF_PAD +
- *headroom);
- }
-
- *frag_count = 1;
- return;
- }
+ if (mtu > MANA_XDP_MTU_MAX)
+ *headroom = 0; /* no support for XDP */
+ else
+ *headroom = XDP_PACKET_HEADROOM;
- /* Standard MTU case - optimize for multiple packets per page */
- *headroom = 0;
+ *alloc_size = SKB_DATA_ALIGN(mtu + MANA_RXBUF_PAD + *headroom);
- /* Calculate base buffer size needed */
- len = SKB_DATA_ALIGN(mtu + MANA_RXBUF_PAD + *headroom);
- buf_size = ALIGN(len, MANA_RX_FRAG_ALIGNMENT);
+ /* Using page pool in this case, so alloc_size is PAGE_SIZE */
+ if (*alloc_size < PAGE_SIZE)
+ *alloc_size = PAGE_SIZE;
- /* Calculate how many packets can fit in a page */
- *frag_count = PAGE_SIZE / buf_size;
- *alloc_size = buf_size;
+ *datasize = mtu + ETH_HLEN;
}
int mana_pre_alloc_rxbufs(struct mana_port_context *mpc, int new_mtu)
@@ -668,9 +640,8 @@ int mana_pre_alloc_rxbufs(struct mana_port_context *mpc, int new_mtu)
void *va;
int i;
- mana_get_rxbuf_cfg(mpc, new_mtu, &mpc->rxbpre_datasize,
- &mpc->rxbpre_alloc_size, &mpc->rxbpre_headroom,
- &mpc->rxbpre_frag_count);
+ mana_get_rxbuf_cfg(new_mtu, &mpc->rxbpre_datasize,
+ &mpc->rxbpre_alloc_size, &mpc->rxbpre_headroom);
dev = mpc->ac->gdma_dev->gdma_context->dev;
@@ -1674,11 +1645,8 @@ static void mana_rx_skb(void *buf_va, bool from_pool,
drop:
if (from_pool) {
- if (rxq->frag_count == 1)
- page_pool_recycle_direct(rxq->page_pool,
- virt_to_head_page(buf_va));
- else
- page_pool_put_page(rxq->page_pool, virt_to_head_page(buf_va), -1, true);
+ page_pool_recycle_direct(rxq->page_pool,
+ virt_to_head_page(buf_va));
} else {
WARN_ON_ONCE(rxq->xdp_save_va);
/* Save for reuse */
@@ -1694,46 +1662,33 @@ static void *mana_get_rxfrag(struct mana_rxq *rxq, struct device *dev,
dma_addr_t *da, bool *from_pool)
{
struct page *page;
- u32 offset;
void *va;
- *from_pool = false;
- /* Don't use fragments for jumbo frames or XDP where it's 1 fragment
- * per page.
- */
- if (rxq->frag_count == 1) {
- /* Reuse XDP dropped page if available */
- if (rxq->xdp_save_va) {
- va = rxq->xdp_save_va;
- page = virt_to_head_page(va);
- rxq->xdp_save_va = NULL;
- } else {
- page = page_pool_dev_alloc_pages(rxq->page_pool);
- if (!page)
- return NULL;
-
- *from_pool = true;
- va = page_to_virt(page);
- }
+ *from_pool = false;
- *da = dma_map_single(dev, va + rxq->headroom, rxq->datasize,
- DMA_FROM_DEVICE);
- if (dma_mapping_error(dev, *da)) {
- mana_put_rx_page(rxq, page, *from_pool);
+ /* Reuse XDP dropped page if available */
+ if (rxq->xdp_save_va) {
+ va = rxq->xdp_save_va;
+ rxq->xdp_save_va = NULL;
+ } else {
+ page = page_pool_dev_alloc_pages(rxq->page_pool);
+ if (!page)
return NULL;
- }
- return va;
+ *from_pool = true;
+ va = page_to_virt(page);
}
- page = page_pool_dev_alloc_frag(rxq->page_pool, &offset,
- rxq->alloc_size);
- if (!page)
- return NULL;
+ *da = dma_map_single(dev, va + rxq->headroom, rxq->datasize,
+ DMA_FROM_DEVICE);
+ if (dma_mapping_error(dev, *da)) {
+ if (*from_pool)
+ page_pool_put_full_page(rxq->page_pool, page, false);
+ else
+ put_page(virt_to_head_page(va));
- va = page_to_virt(page) + offset;
- *da = page_pool_get_dma_addr(page) + offset + rxq->headroom;
- *from_pool = true;
+ return NULL;
+ }
return va;
}
@@ -1750,9 +1705,9 @@ static void mana_refill_rx_oob(struct device *dev, struct mana_rxq *rxq,
va = mana_get_rxfrag(rxq, dev, &da, &from_pool);
if (!va)
return;
- if (!rxoob->from_pool || rxq->frag_count == 1)
- dma_unmap_single(dev, rxoob->sgl[0].address, rxq->datasize,
- DMA_FROM_DEVICE);
+
+ dma_unmap_single(dev, rxoob->sgl[0].address, rxq->datasize,
+ DMA_FROM_DEVICE);
*old_buf = rxoob->buf_va;
*old_fp = rxoob->from_pool;
@@ -2158,15 +2113,15 @@ static void mana_destroy_rxq(struct mana_port_context *apc,
if (!rx_oob->buf_va)
continue;
+ dma_unmap_single(dev, rx_oob->sgl[0].address,
+ rx_oob->sgl[0].size, DMA_FROM_DEVICE);
+
page = virt_to_head_page(rx_oob->buf_va);
- if (rxq->frag_count == 1 || !rx_oob->from_pool) {
- dma_unmap_single(dev, rx_oob->sgl[0].address,
- rx_oob->sgl[0].size, DMA_FROM_DEVICE);
- mana_put_rx_page(rxq, page, rx_oob->from_pool);
- } else {
- page_pool_put_page(rxq->page_pool, virt_to_head_page(rx_oob->buf_va), -1, true);
- }
+ if (rx_oob->from_pool)
+ page_pool_put_full_page(rxq->page_pool, page, false);
+ else
+ put_page(page);
rx_oob->buf_va = NULL;
}
@@ -2272,19 +2227,9 @@ static int mana_create_page_pool(struct mana_rxq *rxq, struct gdma_context *gc)
struct page_pool_params pprm = {};
int ret;
- pprm.pool_size = mpc->rx_queue_size / rxq->frag_count + 1;
+ pprm.pool_size = mpc->rx_queue_size;
pprm.nid = gc->numa_node;
pprm.order = get_order(rxq->alloc_size);
- pprm.dev = gc->dev;
-
- /* Let the page pool do the dma map when page sharing with multiple
- * fragments enabled for rx buffers.
- */
- if (rxq->frag_count > 1) {
- pprm.flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV;
- pprm.max_len = PAGE_SIZE;
- pprm.dma_dir = DMA_FROM_DEVICE;
- }
rxq->page_pool = page_pool_create(&pprm);
@@ -2323,8 +2268,9 @@ static struct mana_rxq *mana_create_rxq(struct mana_port_context *apc,
rxq->rxq_idx = rxq_idx;
rxq->rxobj = INVALID_MANA_HANDLE;
- mana_get_rxbuf_cfg(apc, ndev->mtu, &rxq->datasize, &rxq->alloc_size,
- &rxq->headroom, &rxq->frag_count);
+ 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, gc);
if (err) {
diff --git a/include/net/mana/mana.h b/include/net/mana/mana.h
index dfc929f0b8c6e..4d6d6699a9069 100644
--- a/include/net/mana/mana.h
+++ b/include/net/mana/mana.h
@@ -62,8 +62,6 @@ enum TRI_STATE {
#define MANA_STATS_RX_COUNT 5
#define MANA_STATS_TX_COUNT 11
-#define MANA_RX_FRAG_ALIGNMENT 64
-
struct mana_stats_rx {
u64 packets;
u64 bytes;
@@ -327,7 +325,6 @@ struct mana_rxq {
u32 datasize;
u32 alloc_size;
u32 headroom;
- u32 frag_count;
mana_handle_t rxobj;
@@ -490,7 +487,6 @@ struct mana_port_context {
u32 rxbpre_datasize;
u32 rxbpre_alloc_size;
u32 rxbpre_headroom;
- u32 rxbpre_frag_count;
struct bpf_prog *bpf_prog;
--
2.43.0
More information about the kernel-team
mailing list