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>,
Alexander Duyck <alexander.duyck@gmail.com>,
Jesper Dangaard Brouer <hawk@kernel.org>,
Ilias Apalodimas <ilias.apalodimas@linaro.org>,
Eric Dumazet <edumazet@google.com>,
Jonathan Corbet <corbet@lwn.net>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
John Fastabend <john.fastabend@gmail.com>,
<linux-doc@vger.kernel.org>, <bpf@vger.kernel.org>
Subject: Re: [PATCH net-next v4 5/5] page_pool: update document about frag API
Date: Tue, 13 Jun 2023 21:40:41 -0700 [thread overview]
Message-ID: <20230613214041.1c29a357@kernel.org> (raw)
In-Reply-To: <20230612130256.4572-6-linyunsheng@huawei.com>
On Mon, 12 Jun 2023 21:02:56 +0800 Yunsheng Lin wrote:
> +2. page_pool_alloc_frag(): allocate memory with page splitting when driver knows
> + that the memory it need is always smaller than or equal to half of the page
> + allocated from page pool. Page splitting enables memory saving and thus avoid
> + TLB/cache miss for data access, but there also is some cost to implement page
> + splitting, mainly some cache line dirtying/bouncing for 'struct page' and
> + atomic operation for page->pp_frag_count.
> +
> +3. page_pool_alloc(): allocate memory with or without page splitting depending
> + on the requested memory size when driver doesn't know the size of memory it
> + need beforehand. It is a mix of the above two case, so it is a wrapper of the
> + above API to simplify driver's interface for memory allocation with least
> + memory utilization and performance penalty.
Seems like the semantics of page_pool_alloc() are always better than
page_pool_alloc_frag(). Is there a reason to keep these two separate?
next prev parent reply other threads:[~2023-06-14 4:40 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20230612130256.4572-1-linyunsheng@huawei.com>
2023-06-12 13:02 ` [PATCH net-next v4 5/5] page_pool: update document about frag API Yunsheng Lin
2023-06-14 4:40 ` Jakub Kicinski [this message]
2023-06-14 12:04 ` Yunsheng Lin
2023-06-14 16:56 ` Jakub Kicinski
2023-06-15 6:49 ` Yunsheng Lin
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