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Date: Wed, 14 Jun 2023 10:19:54 -0700
From: Jakub Kicinski <kuba@kernel.org>
To: Yunsheng Lin <linyunsheng@huawei.com>
Cc: <davem@davemloft.net>, <pabeni@redhat.com>, <netdev@vger.kernel.org>,
 <linux-kernel@vger.kernel.org>, Lorenzo Bianconi <lorenzo@kernel.org>,
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Subject: Re: [PATCH net-next v4 4/5] page_pool: remove PP_FLAG_PAGE_FRAG
 flag
Message-ID: <20230614101954.30112d6e@kernel.org>
In-Reply-To: <20230612130256.4572-5-linyunsheng@huawei.com>
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On Mon, 12 Jun 2023 21:02:55 +0800 Yunsheng Lin wrote:
>  	struct page_pool_params pp_params = {
> -		.flags = PP_FLAG_DMA_MAP | PP_FLAG_PAGE_FRAG |
> -				PP_FLAG_DMA_SYNC_DEV,
> +		.flags = PP_FLAG_DMA_MAP | PP_FLAG_DMA_SYNC_DEV,
>  		.order = hns3_page_order(ring),

Does hns3_page_order() set a good example for the users?

static inline unsigned int hns3_page_order(struct hns3_enet_ring *ring)
{
#if (PAGE_SIZE < 8192)
	if (ring->buf_size > (PAGE_SIZE / 2))
		return 1;
#endif
	return 0;
}

Why allocate order 1 pages for buffers which would fit in a single page?
I feel like this soft of heuristic should be built into the API itself.