From: Matteo Croce mcroce@microsoft.com
mainline inclusion from mainline-v5.14-rc1 commit 2f128eb3308a category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I4CVS3 CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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Most of the time during the RX is caused by the compound_head() call done at the end of the RX loop:
│ build_skb(): [...] │ static inline struct page *compound_head(struct page *page) │ { │ unsigned long head = READ_ONCE(page->compound_head); 65.23 │ ldr x2, [x1, #8]
Prefetch the page struct as soon as possible, to speedup the RX path noticeabily by a ~3-4% packet rate in a drop test.
│ build_skb(): [...] │ static inline struct page *compound_head(struct page *page) │ { │ unsigned long head = READ_ONCE(page->compound_head); 17.92 │ ldr x2, [x1, #8]
Signed-off-by: Matteo Croce mcroce@microsoft.com Signed-off-by: David S. Miller davem@davemloft.net Reviewed-by: Yongxin Li liyongxin1@huawei.com Signed-off-by: Junxin Chen chenjunxin1@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c index 55c6f90f818b..42ad6c15db16 100644 --- a/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c +++ b/drivers/net/ethernet/marvell/mvpp2/mvpp2_main.c @@ -3542,15 +3542,19 @@ static int mvpp2_rx(struct mvpp2_port *port, struct napi_struct *napi, phys_addr_t phys_addr; u32 rx_status, timestamp; int pool, rx_bytes, err, ret; + struct page *page; void *data;
+ phys_addr = mvpp2_rxdesc_cookie_get(port, rx_desc); + data = (void *)phys_to_virt(phys_addr); + page = virt_to_page(data); + prefetch(page); + rx_done++; rx_status = mvpp2_rxdesc_status_get(port, rx_desc); rx_bytes = mvpp2_rxdesc_size_get(port, rx_desc); rx_bytes -= MVPP2_MH_SIZE; dma_addr = mvpp2_rxdesc_dma_addr_get(port, rx_desc); - phys_addr = mvpp2_rxdesc_cookie_get(port, rx_desc); - data = (void *)phys_to_virt(phys_addr);
pool = (rx_status & MVPP2_RXD_BM_POOL_ID_MASK) >> MVPP2_RXD_BM_POOL_ID_OFFS; @@ -3639,7 +3643,7 @@ static int mvpp2_rx(struct mvpp2_port *port, struct napi_struct *napi, }
if (pp) - skb_mark_for_recycle(skb, virt_to_page(data), pp); + skb_mark_for_recycle(skb, page, pp); else dma_unmap_single_attrs(dev->dev.parent, dma_addr, bm_pool->buf_size, DMA_FROM_DEVICE,