From: Jonathan Lemon <[email protected]>
To: Christoph Hellwig <[email protected]>
Cc: Jonathan Lemon <[email protected]>, [email protected]
Subject: Re: [PATCH v1 05/15] io_uring: mark pages in ifq region with zctap information.
Date: Thu, 17 Nov 2022 12:48:53 -0800 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
On 16 Nov 2022, at 0:12, Christoph Hellwig wrote:
> On Mon, Nov 07, 2022 at 09:05:11PM -0800, Jonathan Lemon wrote:
>> The network stack passes up pages, which must be mapped to
>> zctap device buffers in order to get the reference count and
>> other items. Mark the page as private, and use the page_private
>> field to record the lookup and ownership information.
>
> Who coordinate ownership of page_private here? What other parts
> of the kernel could touch these pages?
This may be an issue. The driver, network stack, and application
all utilize the pages, which have been pinned by io_uring. If the
pages are passed to another subsystem which wants to use the private
area for its own purposes, there will be a conflict.
There doesn’t seem to be a good way to maintain long term information
in the current page structure. A resolution for this would be using
an external lookup indexed by the page, or changing the information
passed up in the skb.
—
Jonathan
next prev parent reply other threads:[~2022-11-17 20:49 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-08 5:05 [PATCH v1 00/15] zero-copy RX for io_uring Jonathan Lemon
2022-11-08 5:05 ` [PATCH v1 01/15] io_uring: add zctap ifq definition Jonathan Lemon
2022-11-08 5:05 ` [PATCH v1 02/15] netdevice: add SETUP_ZCTAP to the netdev_bpf structure Jonathan Lemon
2022-11-08 5:05 ` [PATCH v1 03/15] io_uring: add register ifq opcode Jonathan Lemon
2022-11-08 5:05 ` [PATCH v1 04/15] io_uring: create a zctap region for a mapped buffer Jonathan Lemon
2022-11-08 5:05 ` [PATCH v1 05/15] io_uring: mark pages in ifq region with zctap information Jonathan Lemon
2022-11-16 8:12 ` Christoph Hellwig
2022-11-17 20:48 ` Jonathan Lemon [this message]
2022-11-08 5:05 ` [PATCH v1 06/15] io_uring: Provide driver API for zctap packet buffers Jonathan Lemon
2022-11-16 8:17 ` Christoph Hellwig
2022-11-17 21:01 ` Jonathan Lemon
2022-11-08 5:05 ` [PATCH v1 07/15] io_uring: Allocate zctap device buffers and dma map them Jonathan Lemon
2022-11-16 8:15 ` Christoph Hellwig
2022-11-17 20:51 ` Jonathan Lemon
2022-11-08 5:05 ` [PATCH v1 08/15] io_uring: Add zctap buffer get/put functions and refcounting Jonathan Lemon
2022-11-08 5:05 ` [PATCH v1 09/15] skbuff: Introduce SKBFL_FIXED_FRAG and skb_fixed() Jonathan Lemon
2022-11-08 5:05 ` [PATCH v1 10/15] io_uring: Allocate a uarg for use by the ifq RX Jonathan Lemon
2022-11-08 5:05 ` [PATCH v1 11/15] io_uring: Define the zctap iov[] returned to the user Jonathan Lemon
2022-11-08 5:05 ` [PATCH v1 12/15] io_uring: add OP_RECV_ZC command Jonathan Lemon
2022-11-08 5:05 ` [PATCH v1 13/15] io_uring: Make remove_ifq_region a delayed work call Jonathan Lemon
2022-11-08 5:05 ` [PATCH v1 14/15] io_uring: Add a buffer caching mechanism for zctap Jonathan Lemon
2022-11-08 5:05 ` [PATCH v1 15/15] io_uring: Notify the application as the fillq is drained Jonathan Lemon
2022-11-09 6:37 ` [PATCH v1 00/15] zero-copy RX for io_uring Dust Li
2022-11-09 15:27 ` Jonathan Lemon
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