From: Byungchul Park <byungchul@sk.com>
To: Jakub Kicinski <kuba@kernel.org>
Cc: linux-mm@kvack.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, kernel_team@skhynix.com,
harry.yoo@oracle.com, ast@kernel.org, daniel@iogearbox.net,
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tariqt@nvidia.com, mbloch@nvidia.com, andrew+netdev@lunn.ch,
edumazet@google.com, pabeni@redhat.com,
akpm@linux-foundation.org, david@redhat.com,
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mhocko@suse.com, horms@kernel.org, jackmanb@google.com,
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linux-rdma@vger.kernel.org, sfr@canb.auug.org.au, dw@davidwei.uk,
ap420073@gmail.com, dtatulea@nvidia.com
Subject: Re: [RFC mm v5 1/2] page_pool: check nmdesc->pp to see its usage as page pool for net_iov not page-backed
Date: Fri, 7 Nov 2025 10:59:02 +0900 [thread overview]
Message-ID: <20251107015902.GA3021@system.software.com> (raw)
In-Reply-To: <20251106173320.2f8e683a@kernel.org>
On Thu, Nov 06, 2025 at 05:33:20PM -0800, Jakub Kicinski wrote:
> On Mon, 3 Nov 2025 16:51:07 +0900 Byungchul Park wrote:
> > However, for net_iov not
^
*not* page-backed
> > page-backed, the identification cannot be based on the page_type.
> > Instead, nmdesc->pp can be used to see if it belongs to a page pool, by
> > making sure nmdesc->pp is NULL otherwise.
>
> Please explain why. Isn't the type just a value in a field?
> Which net_iov could also set accordingly.. ?
page_type field is in 'struct page', so 'struct page' can check the type.
However, the field is not in 'struct net_iov', so 'struct net_iov' that
is not backed by page, cannot use the type checking to see if it's page
pool'ed instance.
I'm afraid I didn't get your questions. I will try to explain again
properly if you give me more detail and example about your questions or
requirement.
Byungchul
next prev parent reply other threads:[~2025-11-07 1:59 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-03 7:51 [RFC mm v5 0/2] mm, page_pool: introduce a new page type for page pool in page type Byungchul Park
2025-11-03 7:51 ` [RFC mm v5 1/2] page_pool: check nmdesc->pp to see its usage as page pool for net_iov not page-backed Byungchul Park
2025-11-03 12:24 ` Toke Høiland-Jørgensen
2025-11-06 11:07 ` Pavel Begunkov
2025-11-07 1:33 ` Jakub Kicinski
2025-11-07 1:59 ` Byungchul Park [this message]
2025-11-07 2:08 ` Jakub Kicinski
2025-11-07 4:47 ` Byungchul Park
2025-11-08 1:41 ` Jakub Kicinski
2025-11-08 2:24 ` Byungchul Park
2025-11-08 2:29 ` Byungchul Park
2025-11-08 2:37 ` Jakub Kicinski
2025-11-10 1:09 ` Byungchul Park
2025-11-11 1:40 ` Byungchul Park
2025-11-11 1:56 ` Jakub Kicinski
2025-11-11 2:17 ` Byungchul Park
2025-11-11 2:45 ` Byungchul Park
2025-11-11 12:36 ` Toke Høiland-Jørgensen
2025-11-03 7:51 ` [RFC mm v5 2/2] mm: introduce a new page type for page pool in page type Byungchul Park
2025-11-03 12:26 ` Toke Høiland-Jørgensen
2025-11-03 12:39 ` Byungchul Park
2025-11-03 14:50 ` Toke Høiland-Jørgensen
2025-11-06 11:08 ` Pavel Begunkov
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