Messages in this thread | | | Subject | Re: [PATCH RFC net-next v4 5/9] libie: add Rx buffer management (via Page Pool) | From | Yunsheng Lin <> | Date | Thu, 6 Jul 2023 20:47:28 +0800 |
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On 2023/7/5 23:55, Alexander Lobakin wrote:
> +/** > + * libie_rx_page_pool_create - create a PP with the default libie settings > + * @napi: &napi_struct covering this PP (no usage outside its poll loops) > + * @size: size of the PP, usually simply Rx queue len > + * > + * Returns &page_pool on success, casted -errno on failure. > + */ > +struct page_pool *libie_rx_page_pool_create(struct napi_struct *napi, > + u32 size) > +{ > + struct page_pool_params pp = { > + .flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV, > + .order = LIBIE_RX_PAGE_ORDER, > + .pool_size = size, > + .nid = NUMA_NO_NODE, > + .dev = napi->dev->dev.parent, > + .napi = napi, > + .dma_dir = DMA_FROM_DEVICE, > + .offset = LIBIE_SKB_HEADROOM,
I think it worth mentioning that the '.offset' is not really accurate when the page is split, as we do not really know what is the offset of the frag of a page except for the first frag.
> + }; > + size_t truesize; > + > + pp.max_len = libie_rx_sync_len(napi->dev, pp.offset); > + > + /* "Wanted" truesize, passed to page_pool_dev_alloc() */ > + truesize = roundup_pow_of_two(SKB_HEAD_ALIGN(pp.offset + pp.max_len)); > + pp.init_arg = (void *)truesize;
I am not sure if it is correct to use pp.init_arg here, as it is supposed to be used along with init_callback. And if we want to change the implemetation of init_callback, we may stuck with it as the driver is using it very differently here.
Is it possible to pass the 'wanted true size' by adding a parameter for libie_rx_alloc()?
> + > + return page_pool_create(&pp); > +} > +EXPORT_SYMBOL_NS_GPL(libie_rx_page_pool_create, LIBIE);
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