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Message-Id: <20230518180545.159100-12-maciej.fijalkowski@intel.com>
Date: Thu, 18 May 2023 20:05:35 +0200
From: Maciej Fijalkowski <maciej.fijalkowski@...el.com>
To: bpf@...r.kernel.org,
ast@...nel.org,
daniel@...earbox.net,
andrii@...nel.org
Cc: netdev@...r.kernel.org,
magnus.karlsson@...el.com,
tirthendu.sarkar@...el.com,
maciej.fijalkowski@...el.com,
bjorn@...nel.org
Subject: [PATCH bpf-next 11/21] ice: xsk: add RX multi-buffer support
This support is strongly inspired by work that introduced multi-buffer
support to regular Rx data path in ice. There are some differences,
though. When adding a frag, besides adding it to skb_shared_info, use
also fresh xsk_buff_add_frag() helper. Reason for doing both things is
that we can not rule out the fact that AF_XDP pipeline could use XDP
program that needs to access frame fragments. Without them being in
skb_shared_info it will not be possible. Another difference is that
XDP_PASS has to allocate a new pages for each frags and copy contents
from memory backed by xsk_buff_pool.
chain_len that is used for programming HW Rx descriptors no longer has
to be limited to 1 when xsk_pool is present - remove this restriction.
Signed-off-by: Maciej Fijalkowski <maciej.fijalkowski@...el.com>
---
drivers/net/ethernet/intel/ice/ice_base.c | 9 +-
drivers/net/ethernet/intel/ice/ice_xsk.c | 136 ++++++++++++++++------
2 files changed, 102 insertions(+), 43 deletions(-)
diff --git a/drivers/net/ethernet/intel/ice/ice_base.c b/drivers/net/ethernet/intel/ice/ice_base.c
index 1911d644dfa8..b790e3d6be6f 100644
--- a/drivers/net/ethernet/intel/ice/ice_base.c
+++ b/drivers/net/ethernet/intel/ice/ice_base.c
@@ -366,7 +366,6 @@ static unsigned int ice_rx_offset(struct ice_rx_ring *rx_ring)
*/
static int ice_setup_rx_ctx(struct ice_rx_ring *ring)
{
- int chain_len = ICE_MAX_CHAINED_RX_BUFS;
struct ice_vsi *vsi = ring->vsi;
u32 rxdid = ICE_RXDID_FLEX_NIC;
struct ice_rlan_ctx rlan_ctx;
@@ -430,17 +429,11 @@ static int ice_setup_rx_ctx(struct ice_rx_ring *ring)
*/
rlan_ctx.showiv = 0;
- /* For AF_XDP ZC, we disallow packets to span on
- * multiple buffers, thus letting us skip that
- * handling in the fast-path.
- */
- if (ring->xsk_pool)
- chain_len = 1;
/* Max packet size for this queue - must not be set to a larger value
* than 5 x DBUF
*/
rlan_ctx.rxmax = min_t(u32, vsi->max_frame,
- chain_len * ring->rx_buf_len);
+ ICE_MAX_CHAINED_RX_BUFS * ring->rx_buf_len);
/* Rx queue threshold in units of 64 */
rlan_ctx.lrxqthresh = 1;
diff --git a/drivers/net/ethernet/intel/ice/ice_xsk.c b/drivers/net/ethernet/intel/ice/ice_xsk.c
index d1e489da7363..920cf2b16836 100644
--- a/drivers/net/ethernet/intel/ice/ice_xsk.c
+++ b/drivers/net/ethernet/intel/ice/ice_xsk.c
@@ -548,19 +548,6 @@ bool ice_alloc_rx_bufs_zc(struct ice_rx_ring *rx_ring, u16 count)
return __ice_alloc_rx_bufs_zc(rx_ring, leftover);
}
-/**
- * ice_bump_ntc - Bump the next_to_clean counter of an Rx ring
- * @rx_ring: Rx ring
- */
-static void ice_bump_ntc(struct ice_rx_ring *rx_ring)
-{
- int ntc = rx_ring->next_to_clean + 1;
-
- ntc = (ntc < rx_ring->count) ? ntc : 0;
- rx_ring->next_to_clean = ntc;
- prefetch(ICE_RX_DESC(rx_ring, ntc));
-}
-
/**
* ice_construct_skb_zc - Create an sk_buff from zero-copy buffer
* @rx_ring: Rx ring
@@ -575,8 +562,14 @@ ice_construct_skb_zc(struct ice_rx_ring *rx_ring, struct xdp_buff *xdp)
{
unsigned int totalsize = xdp->data_end - xdp->data_meta;
unsigned int metasize = xdp->data - xdp->data_meta;
+ struct skb_shared_info *sinfo = NULL;
struct sk_buff *skb;
+ u32 nr_frags = 0;
+ if (unlikely(xdp_buff_has_frags(xdp))) {
+ sinfo = xdp_get_shared_info_from_buff(xdp);
+ nr_frags = sinfo->nr_frags;
+ }
net_prefetch(xdp->data_meta);
skb = __napi_alloc_skb(&rx_ring->q_vector->napi, totalsize,
@@ -592,6 +585,29 @@ ice_construct_skb_zc(struct ice_rx_ring *rx_ring, struct xdp_buff *xdp)
__skb_pull(skb, metasize);
}
+ if (likely(!xdp_buff_has_frags(xdp)))
+ goto out;
+
+ for (int i = 0; i < nr_frags; i++) {
+ struct skb_shared_info *skinfo = skb_shinfo(skb);
+ skb_frag_t *frag = &sinfo->frags[i];
+ struct page *page;
+ void *addr;
+
+ page = dev_alloc_page();
+ if (!page) {
+ dev_kfree_skb(skb);
+ return NULL;
+ }
+ addr = page_to_virt(page);
+
+ memcpy(addr, skb_frag_page(frag), skb_frag_size(frag));
+
+ __skb_fill_page_desc_noacc(skinfo, skinfo->nr_frags++,
+ addr, 0, skb_frag_size(frag));
+ }
+
+out:
xsk_buff_free(xdp);
return skb;
}
@@ -755,6 +771,34 @@ ice_run_xdp_zc(struct ice_rx_ring *rx_ring, struct xdp_buff *xdp,
return result;
}
+static int
+ice_add_xsk_frag(struct ice_rx_ring *rx_ring, struct xdp_buff *first,
+ struct xdp_buff *xdp, const unsigned int size)
+{
+ struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(first);
+
+ if (!size)
+ return 0;
+
+ if (!xdp_buff_has_frags(first)) {
+ sinfo->nr_frags = 0;
+ sinfo->xdp_frags_size = 0;
+ xdp_buff_set_frags_flag(first);
+ }
+
+ if (unlikely(sinfo->nr_frags == MAX_SKB_FRAGS)) {
+ xsk_buff_free(first);
+ return -ENOMEM;
+ }
+
+ __skb_fill_page_desc_noacc(sinfo, sinfo->nr_frags++,
+ virt_to_page(xdp->data_hard_start), 0, size);
+ sinfo->xdp_frags_size += size;
+ xsk_buff_add_frag(first, xdp);
+
+ return 0;
+}
+
/**
* ice_clean_rx_irq_zc - consumes packets from the hardware ring
* @rx_ring: AF_XDP Rx ring
@@ -765,9 +809,14 @@ ice_run_xdp_zc(struct ice_rx_ring *rx_ring, struct xdp_buff *xdp,
int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring, int budget)
{
unsigned int total_rx_bytes = 0, total_rx_packets = 0;
+ struct xsk_buff_pool *xsk_pool = rx_ring->xsk_pool;
+ u32 ntc = rx_ring->next_to_clean;
+ u32 ntu = rx_ring->next_to_use;
+ struct xdp_buff *first = NULL;
struct ice_tx_ring *xdp_ring;
unsigned int xdp_xmit = 0;
struct bpf_prog *xdp_prog;
+ u32 cnt = rx_ring->count;
bool failure = false;
int entries_to_alloc;
@@ -777,6 +826,9 @@ int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring, int budget)
xdp_prog = READ_ONCE(rx_ring->xdp_prog);
xdp_ring = rx_ring->xdp_ring;
+ if (ntc != rx_ring->first_desc)
+ first = *ice_xdp_buf(rx_ring, rx_ring->first_desc);
+
while (likely(total_rx_packets < (unsigned int)budget)) {
union ice_32b_rx_flex_desc *rx_desc;
unsigned int size, xdp_res = 0;
@@ -786,7 +838,7 @@ int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring, int budget)
u16 vlan_tag = 0;
u16 rx_ptype;
- rx_desc = ICE_RX_DESC(rx_ring, rx_ring->next_to_clean);
+ rx_desc = ICE_RX_DESC(rx_ring, ntc);
stat_err_bits = BIT(ICE_RX_FLEX_DESC_STATUS0_DD_S);
if (!ice_test_staterr(rx_desc->wb.status_error0, stat_err_bits))
@@ -798,51 +850,61 @@ int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring, int budget)
*/
dma_rmb();
- if (unlikely(rx_ring->next_to_clean == rx_ring->next_to_use))
+ if (unlikely(ntc == ntu))
break;
- xdp = *ice_xdp_buf(rx_ring, rx_ring->next_to_clean);
+ xdp = *ice_xdp_buf(rx_ring, ntc);
size = le16_to_cpu(rx_desc->wb.pkt_len) &
ICE_RX_FLX_DESC_PKT_LEN_M;
- if (!size) {
- xdp->data = NULL;
- xdp->data_end = NULL;
- xdp->data_hard_start = NULL;
- xdp->data_meta = NULL;
- goto construct_skb;
- }
xsk_buff_set_size(xdp, size);
- xsk_buff_dma_sync_for_cpu(xdp, rx_ring->xsk_pool);
+ xsk_buff_dma_sync_for_cpu(xdp, xsk_pool);
+
+ if (!first) {
+ first = xdp;
+ xdp_buff_clear_frags_flag(first);
+ } else if (ice_add_xsk_frag(rx_ring, first, xdp, size)) {
+ break;
+ }
+
+ if (++ntc == cnt)
+ ntc = 0;
+
+ if (ice_is_non_eop(rx_ring, rx_desc))
+ continue;
- xdp_res = ice_run_xdp_zc(rx_ring, xdp, xdp_prog, xdp_ring);
+ xdp_res = ice_run_xdp_zc(rx_ring, first, xdp_prog, xdp_ring);
if (likely(xdp_res & (ICE_XDP_TX | ICE_XDP_REDIR))) {
xdp_xmit |= xdp_res;
} else if (xdp_res == ICE_XDP_EXIT) {
failure = true;
+ first = NULL;
+ rx_ring->first_desc = ntc;
break;
} else if (xdp_res == ICE_XDP_CONSUMED) {
- xsk_buff_free(xdp);
+ xsk_buff_free(first);
} else if (xdp_res == ICE_XDP_PASS) {
goto construct_skb;
}
- total_rx_bytes += size;
+ total_rx_bytes += xdp_get_buff_len(first);
total_rx_packets++;
- ice_bump_ntc(rx_ring);
+ first = NULL;
+ rx_ring->first_desc = ntc;
continue;
construct_skb:
/* XDP_PASS path */
- skb = ice_construct_skb_zc(rx_ring, xdp);
+ skb = ice_construct_skb_zc(rx_ring, first);
if (!skb) {
rx_ring->ring_stats->rx_stats.alloc_buf_failed++;
break;
}
- ice_bump_ntc(rx_ring);
+ first = NULL;
+ rx_ring->first_desc = ntc;
if (eth_skb_pad(skb)) {
skb = NULL;
@@ -861,18 +923,22 @@ int ice_clean_rx_irq_zc(struct ice_rx_ring *rx_ring, int budget)
ice_receive_skb(rx_ring, skb, vlan_tag);
}
- entries_to_alloc = ICE_DESC_UNUSED(rx_ring);
+ rx_ring->next_to_clean = ntc;
+ entries_to_alloc = ICE_RX_DESC_UNUSED(rx_ring);
if (entries_to_alloc > ICE_RING_QUARTER(rx_ring))
failure |= !ice_alloc_rx_bufs_zc(rx_ring, entries_to_alloc);
ice_finalize_xdp_rx(xdp_ring, xdp_xmit, 0);
ice_update_rx_ring_stats(rx_ring, total_rx_packets, total_rx_bytes);
- if (xsk_uses_need_wakeup(rx_ring->xsk_pool)) {
- if (failure || rx_ring->next_to_clean == rx_ring->next_to_use)
- xsk_set_rx_need_wakeup(rx_ring->xsk_pool);
+ if (xsk_uses_need_wakeup(xsk_pool)) {
+ /* ntu could have changed when allocating entries above, so
+ * use rx_ring value instead of stack based one
+ */
+ if (failure || ntc == rx_ring->next_to_use)
+ xsk_set_rx_need_wakeup(xsk_pool);
else
- xsk_clear_rx_need_wakeup(rx_ring->xsk_pool);
+ xsk_clear_rx_need_wakeup(xsk_pool);
return (int)total_rx_packets;
}
--
2.34.1
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