Re: [PATCH V2,net-next] net: mana: Add page pool for RX buffers
From: Jakub Kicinski <kuba@kernel.org>
Date: 2023-07-20 04:29:56
Also in:
bpf, linux-hyperv, linux-rdma, lkml
On Tue, 18 Jul 2023 21:48:01 +0000 Haiyang Zhang wrote:
Add page pool for RX buffers for faster buffer cycle and reduce CPU usage. The standard page pool API is used.
quoted hunk ↗ jump to hunk
@@ -1437,8 +1437,12 @@ static void mana_rx_skb(void *buf_va, struct mana_rxcomp_oob *cqe, act = mana_run_xdp(ndev, rxq, &xdp, buf_va, pkt_len); - if (act == XDP_REDIRECT && !rxq->xdp_rc) + if (act == XDP_REDIRECT && !rxq->xdp_rc) { + if (from_pool) + page_pool_release_page(rxq->page_pool, + virt_to_head_page(buf_va));
IIUC you should pass the page_pool as the last argument to xdp_rxq_info_reg_mem_model() and then the page will be recycled by the core, you shouldn't release it. Not to mention the potential race in releasing the page _after_ giving its ownership to someone else.
- page = dev_alloc_page();
+ if (is_napi) {
+ page = page_pool_dev_alloc_pages(rxq->page_pool);
+ *from_pool = true;
+ } else {
+ page = dev_alloc_page();FWIW if you're only calling this outside NAPI during init, when NAPI can't yet run, I _think_ it's okay to use page_pool_dev_alloc..
+ pprm.pool_size = RX_BUFFERS_PER_QUEUE; + pprm.napi = &cq->napi; + pprm.dev = gc->dev; + pprm.dma_dir = DMA_FROM_DEVICE;
If you're not setting PP_FLAG_DMA_MAP you don't have to fill in .dev and .dma_dir -- pw-bot: cr