From: Stanislav Fomichev <sdf.kernel@gmail.com>
To: Bobby Eshleman <bobbyeshleman@gmail.com>
Cc: "Donald Hunter" <donald.hunter@gmail.com>,
"Jakub Kicinski" <kuba@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
"Eric Dumazet" <edumazet@google.com>,
"Paolo Abeni" <pabeni@redhat.com>,
"Simon Horman" <horms@kernel.org>,
"Andrew Lunn" <andrew+netdev@lunn.ch>,
"Gerd Hoffmann" <kraxel@redhat.com>,
"Vivek Kasireddy" <vivek.kasireddy@intel.com>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"Christian König" <christian.koenig@amd.com>,
"Shuah Khan" <shuah@kernel.org>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org,
linaro-mm-sig@lists.linaro.org, linux-kselftest@vger.kernel.org,
sdf@fomichev.me, razor@blackwall.org, daniel@iogearbox.net,
almasrymina@google.com, matttbe@kernel.org, skhawaja@google.com,
dw@davidwei.uk, "Bobby Eshleman" <bobbyeshleman@meta.com>
Subject: Re: [PATCH net-next 3/4] selftests/net: ncdevmem: add -b option to set rx-buf-size on bind
Date: Fri, 5 Jun 2026 08:35:25 -0700 [thread overview]
Message-ID: <aiLsegSEGviNluv1@devvm7509.cco0.facebook.com> (raw)
In-Reply-To: <20260603-tcpdm-large-niovs-v1-3-f37a4ac6726c@meta.com>
On 06/03, Bobby Eshleman wrote:
> From: Bobby Eshleman <bobbyeshleman@meta.com>
>
> Add -b <bytes> to request a non-default niov size via
> NETDEV_A_DMABUF_RX_BUF_SIZE. When the value exceeds PAGE_SIZE,
> udmabuf_alloc() switches to an MFD_HUGETLB-backed memfd so each 2 MB
> hugepage produces one naturally-aligned sg entry.
>
> Reject values > 2 MB up front: MFD_HUGETLB + udmabuf can only guarantee
> 2 MB per sg entry (one hugepage), so a larger rx_buf_size would fail the
> per-sg length/alignment check.
>
> Add CONFIG_HUGETLBFS=y to drivers/net/hw/config so the new path is
> reachable in the CI kernels built for these tests.
I vaguely remember there was also some kernel cmdline argument to
reserve these? Do we need to also do something to NIPA to reserve 2MB
pages for this test? Or was it for 1GB pages?
next prev parent reply other threads:[~2026-06-05 15:35 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-04 0:42 [PATCH net-next 0/4] net: devmem: allow rx-buf-size > PAGE_SIZE per binding Bobby Eshleman
2026-06-04 0:42 ` [PATCH net-next 1/4] net: devmem: allow rx-buf-size > PAGE_SIZE per dmabuf binding Bobby Eshleman
2026-06-05 15:33 ` Stanislav Fomichev
2026-06-05 16:20 ` Bobby Eshleman
2026-06-04 0:42 ` [PATCH net-next 2/4] udmabuf: emit one sg entry per pinned folio Bobby Eshleman
2026-06-05 9:30 ` Christian König
2026-06-05 18:44 ` Bobby Eshleman
2026-06-04 0:43 ` [PATCH net-next 3/4] selftests/net: ncdevmem: add -b option to set rx-buf-size on bind Bobby Eshleman
2026-06-05 15:35 ` Stanislav Fomichev [this message]
2026-06-05 16:56 ` Bobby Eshleman
2026-06-04 0:43 ` [PATCH net-next 4/4] selftests/net: devmem.py: add check_rx_large_niov Bobby Eshleman
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