linux-kernel - Re: [PATCH net-next 1/9] netmem: introduce struct netmem

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAHS8izP2Y4FMfHyTU6u5NRT45raM9isXJZPY4LMC8c03dGUPJQ@mail.gmail.com>
Date: Wed, 11 Jun 2025 13:53:51 -0700
From: Mina Almasry <almasrymina@...gle.com>
To: Jakub Kicinski <kuba@...nel.org>, David Howells <dhowells@...hat.com>
Cc: Byungchul Park <byungchul@...com>, willy@...radead.org, netdev@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-mm@...ck.org, kernel_team@...ynix.com, 
	ilias.apalodimas@...aro.org, harry.yoo@...cle.com, hawk@...nel.org, 
	akpm@...ux-foundation.org, davem@...emloft.net, john.fastabend@...il.com, 
	andrew+netdev@...n.ch, asml.silence@...il.com, toke@...hat.com, 
	tariqt@...dia.com, edumazet@...gle.com, pabeni@...hat.com, saeedm@...dia.com, 
	leon@...nel.org, ast@...nel.org, daniel@...earbox.net, david@...hat.com, 
	lorenzo.stoakes@...cle.com, Liam.Howlett@...cle.com, vbabka@...e.cz, 
	rppt@...nel.org, surenb@...gle.com, mhocko@...e.com, horms@...nel.org, 
	linux-rdma@...r.kernel.org, bpf@...r.kernel.org, vishal.moola@...il.com
Subject: Re: [PATCH net-next 1/9] netmem: introduce struct netmem_desc
 mirroring struct page

On Mon, Jun 9, 2025 at 12:32 PM Jakub Kicinski <kuba@...nel.org> wrote:
>
> On Mon,  9 Jun 2025 13:32:17 +0900 Byungchul Park wrote:
> > To simplify struct page, the page pool members of struct page should be
> > moved to other, allowing these members to be removed from struct page.
> >
> > Introduce a network memory descriptor to store the members, struct
> > netmem_desc, and make it union'ed with the existing fields in struct
> > net_iov, allowing to organize the fields of struct net_iov.
>
> What's the intended relation between the types?
>
> netmem_ref exists to clearly indicate that memory may not be readable.
> Majority of memory we expect to allocate from page pool must be
> kernel-readable. What's the plan for reading the "single pointer"
> memory within the kernel?
>
> I think you're approaching this problem from the easiest and least
> relevant direction. Are you coordinating with David Howells?

FWIW I did point David to this work in a tangentially related thread:

https://lore.kernel.org/netdev/CAHS8izMMU8QZrvXRiDjqwsBg_34s+dhvSyrU7XGMBuPF6eWyTA@mail.gmail.com/

I think yes it would be good to get a reviewed-by or acked-by from
Matthew or David to show that this approach is in line with their
plans?

>From my end I tried to review to:

1. Make sure the changes are compatible with net_iov/netmem_ref.
2. Make sure what's implemented here is in line with the memdesc
effort Matthew lists here[1]. In particular the netmem_desc struct
introduced here is very similar to the zpdesc and ptdesc structs
mentioned as an example in [1].

[1] https://kernelnewbies.org/MatthewWilcox/Memdescs/Path

-- 
Thanks,
Mina