From: Matteo Croce <[email protected]>
This is a respin of [1]
This patchset shows the plans for allowing page_pool to handle and
maintain DMA map/unmap of the pages it serves to the driver. For this
to work a return hook in the network core is introduced.
The overall purpose is to simplify drivers, by providing a page
allocation API that does recycling, such that each driver doesn't have
to reinvent its own recycling scheme. Using page_pool in a driver
does not require implementing XDP support, but it makes it trivially
easy to do so. Instead of allocating buffers specifically for SKBs
we now allocate a generic buffer and either wrap it on an SKB
(via build_skb) or create an XDP frame.
The recycling code leverages the XDP recycle APIs.
The Marvell mvpp2 and mvneta drivers are used in this patchset to
demonstrate how to use the API, and tested on a MacchiatoBIN
and EspressoBIN boards respectively.
Please let this going in on a future -rc1 so to allow enough time
to have wider tests.
Note that this series depends on the change "mm: fix struct page layout
on 32-bit systems"[2] which is not yet in master.
[1] https://lore.kernel.org/netdev/154413868810.21735.572808840657728172.stgit@firesoul/
[2] https://lore.kernel.org/linux-mm/[email protected]/
Ilias Apalodimas (1):
page_pool: Allow drivers to hint on SKB recycling
Matteo Croce (3):
mm: add a signature in struct page
mvpp2: recycle buffers
mvneta: recycle buffers
drivers/net/ethernet/marvell/mvneta.c | 11 +++---
.../net/ethernet/marvell/mvpp2/mvpp2_main.c | 17 +++++-----
drivers/net/ethernet/marvell/sky2.c | 2 +-
drivers/net/ethernet/mellanox/mlx4/en_rx.c | 2 +-
include/linux/mm_types.h | 1 +
include/linux/skbuff.h | 34 ++++++++++++++++---
include/net/page_pool.h | 11 ++++++
net/core/page_pool.c | 27 +++++++++++++++
net/core/skbuff.c | 20 +++++++++--
net/tls/tls_device.c | 2 +-
10 files changed, 105 insertions(+), 22 deletions(-)
--
2.31.1
From: Matteo Croce <[email protected]>
Use the new recycling API for page_pool.
In a drop rate test, the packet rate increased di 10%,
from 269 Kpps to 296 Kpps.
perf top on a stock system shows:
Overhead Shared Object Symbol
21.78% [kernel] [k] __pi___inval_dcache_area
21.66% [mvneta] [k] mvneta_rx_swbm
7.00% [kernel] [k] kmem_cache_alloc
6.05% [kernel] [k] eth_type_trans
4.44% [kernel] [k] kmem_cache_free.part.0
3.80% [kernel] [k] __netif_receive_skb_core
3.68% [kernel] [k] dev_gro_receive
3.65% [kernel] [k] get_page_from_freelist
3.43% [kernel] [k] page_pool_release_page
3.35% [kernel] [k] free_unref_page
And this is the same output with recycling enabled:
Overhead Shared Object Symbol
24.10% [kernel] [k] __pi___inval_dcache_area
23.02% [mvneta] [k] mvneta_rx_swbm
7.19% [kernel] [k] kmem_cache_alloc
6.50% [kernel] [k] eth_type_trans
4.93% [kernel] [k] __netif_receive_skb_core
4.77% [kernel] [k] kmem_cache_free.part.0
3.93% [kernel] [k] dev_gro_receive
3.03% [kernel] [k] build_skb
2.91% [kernel] [k] page_pool_put_page
2.85% [kernel] [k] __xdp_return
The test was done with mausezahn on the TX side with 64 byte raw
ethernet frames.
Signed-off-by: Matteo Croce <[email protected]>
---
drivers/net/ethernet/marvell/mvneta.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
index 7d5cd9bc6c99..6d2f8dce4900 100644
--- a/drivers/net/ethernet/marvell/mvneta.c
+++ b/drivers/net/ethernet/marvell/mvneta.c
@@ -2320,7 +2320,7 @@ mvneta_swbm_add_rx_fragment(struct mvneta_port *pp,
}
static struct sk_buff *
-mvneta_swbm_build_skb(struct mvneta_port *pp, struct mvneta_rx_queue *rxq,
+mvneta_swbm_build_skb(struct mvneta_port *pp, struct page_pool *pool,
struct xdp_buff *xdp, u32 desc_status)
{
struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp);
@@ -2331,7 +2331,7 @@ mvneta_swbm_build_skb(struct mvneta_port *pp, struct mvneta_rx_queue *rxq,
if (!skb)
return ERR_PTR(-ENOMEM);
- page_pool_release_page(rxq->page_pool, virt_to_page(xdp->data));
+ skb_mark_for_recycle(skb, virt_to_page(xdp->data), pool);
skb_reserve(skb, xdp->data - xdp->data_hard_start);
skb_put(skb, xdp->data_end - xdp->data);
@@ -2343,7 +2343,10 @@ mvneta_swbm_build_skb(struct mvneta_port *pp, struct mvneta_rx_queue *rxq,
skb_add_rx_frag(skb, skb_shinfo(skb)->nr_frags,
skb_frag_page(frag), skb_frag_off(frag),
skb_frag_size(frag), PAGE_SIZE);
- page_pool_release_page(rxq->page_pool, skb_frag_page(frag));
+ /* We don't need to reset pp_recycle here. It's already set, so
+ * just mark fragments for recycling.
+ */
+ page_pool_store_mem_info(skb_frag_page(frag), pool);
}
return skb;
@@ -2425,7 +2428,7 @@ static int mvneta_rx_swbm(struct napi_struct *napi,
mvneta_run_xdp(pp, rxq, xdp_prog, &xdp_buf, frame_sz, &ps))
goto next;
- skb = mvneta_swbm_build_skb(pp, rxq, &xdp_buf, desc_status);
+ skb = mvneta_swbm_build_skb(pp, pp, &xdp_buf, desc_status);
if (IS_ERR(skb)) {
struct mvneta_pcpu_stats *stats = this_cpu_ptr(pp->stats);
--
2.31.1