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* [RFC net v2 0/2] af_packet: retire TPACKET_V3 blocks without waiting for copiers
@ 2026-10-30  8:17 Jingxuan Xie
  2026-10-30  8:17 ` [RFC net v2 1/2] af_packet: prepare the virtio header before reserving an RX frame Jingxuan Xie
  2026-10-30  8:17 ` [RFC net v2 2/2] af_packet: retire TPACKET_V3 blocks without waiting for copiers Jingxuan Xie
  0 siblings, 2 replies; 6+ messages in thread
From: Jingxuan Xie @ 2026-10-30  8:17 UTC (permalink / raw)
  To: netdev
  Cc: Willem de Bruijn, David S . Miller, Eric Dumazet, Jakub Kicinski,
	Paolo Abeni, Simon Horman, Sebastian Andrzej Siewior,
	Clark Williams, Steven Rostedt, John Ogness, linux-kernel,
	linux-rt-devel

This revision keeps asynchronous block retirement but removes completion-side
queue locking, the four-state enum, the eight-block publication budget and
the workqueue used in v1. Private copy accounting now lives in the existing
pgv allocation. Packet allocation and the existing retirement timer publish
ready blocks in order under their existing receive queue lock.

A preempted copier in a sealed block does not prevent capture into the next
available block. Copy completion only performs a release decrement. In the
absence of further traffic, publication may wait for a later timer callback;
there is no hard bound under RT starvation. A finite ring can still exhaust.

Patch 1 independently moves virtio RX-header preparation ahead of frame
reservation. Patch 2 implements the retirement change. Neither patch changes
the mmap layout or adds a UAPI.

Changes since v1, in response to Willem de Bruijn:
- Split virtio header preparation into its own patch.
- Remove the second receive queue lock acquisition from copy completion.
- Remove the state enum, separate metadata allocation and worker lifecycle.
- Replace the fixed publication budget with a loop over existing ready blocks.
- Use release completion and acquire observation of per-block counts.
- Permit idle delivery to wait for the existing retirement timer.

Testing: ARM64 QEMU virt, four CPUs, PREEMPT_RT and lockdep. The unmodified
retirement logic blocks sender B behind a deliberately delayed copier A.
With v2, B completes capture before A is released, for full-block and timer
retirement; idle delivery, block sequence, lengths and payload are checked.
The delay is introduced by validation-only kernel instrumentation and is
not included in this series. Ordinary psock_tpacket and psock_fanout pass
on uninstrumented RT and non-RT builds. External validation tests exercise
the actual private helpers; LKMM tests check multi-copier ordering.

The ready-block loop has no fixed work budget: a large ready backlog can
lengthen the receive queue critical section. A validation case publishes
1000 blocks in one call. This tradeoff is explicitly retained for review.
Separate RT KASAN and strict KCSAN runs pass the helper checks, psock tests,
delayed-copy tests and concurrent-close test without sanitizer reports.
Patch 1 also passes an independent malformed-GSO runtime check. ARM64 W=1
packet-object builds pass for each patch and under allyesconfig/allmodconfig.
QEMU does not establish hardware NIC or Orin integration acceptance.

v1:
https://lore.kernel.org/netdev/20261028070528.139531-1-jingxuanxie@deeproute.ai/

Review:
https://lore.kernel.org/netdev/willemdebruijn.kernel.31ae9fde05c@gmail.com/

Base: fcc00b15cb21a6de76826e5012b2c758505f5e65 (net/main).

jingxuanxie (2):
  af_packet: prepare the virtio header before reserving an RX frame
  af_packet: retire TPACKET_V3 blocks without waiting for copiers

 net/packet/af_packet.c | 162 +++++++++++++++++++++----------------------
 net/packet/internal.h  |   9 ++-
 2 files changed, 88 insertions(+), 83 deletions(-)


base-commit: fcc00b15cb21a6de76826e5012b2c758505f5e65
--
2.25.1

________________________________


本电子邮件及转载的任何文件都属绝密文件，并且仅供标明地址的个人或团体使用。如果您收到的电子邮件存在错误，请通知本公司，删除全部原始信息（包括任何原始信息的备份），并且禁止散布或分发全部或部分原始信息。本公司不担保本电子邮件中信息的准确性、适当性或完整性，并且对此产生的任何错误或疏忽不承担任何责任。在正式协议签订以前，这里提到的任何参考术语、与主题相关的情形以及随后的电子邮件中的谈判，都将严格“遵守合同”。接收方应在接收电子邮件或任何附件时检查有无病毒，本公司对由于转载本电子邮件而引发病毒产生的任何损坏不承担任何责任。


Reproduced in this e-mail and any files are considered top-secret documents, and only indicate the address of individuals or groups. If you receive an e-mail there is an error, please notify the Company, delete all the original information (including any backup of the original information), and the prohibition of the dissemination or distribution of all or part of the original information. The Company does not guarantee the accuracy of the information in this e-mail, adequacy, or completeness, and this produces any error or omission does not bear any responsibility. The formal agreement was signed prior to any reference to the term mentioned here, and the circumstances relevant to the subject and subsequent e-mail in the negotiations will be strictly "comply with the contract." The receiver should be receiving an e-mail or any attachment, check for viruses. The company reproduced this e-mail because of the virus caused any damage resulting from not bear any responsibility.

^ permalink raw reply	[flat|nested] 6+ messages in thread
* [RFC net v2 0/2] af_packet: retire TPACKET_V3 blocks without waiting for copiers
@ 2026-10-30  8:14 Jingxuan Xie
  2026-10-30  8:14 ` [RFC net v2 1/2] af_packet: prepare the virtio header before reserving an RX frame Jingxuan Xie
  0 siblings, 1 reply; 6+ messages in thread
From: Jingxuan Xie @ 2026-10-30  8:14 UTC (permalink / raw)
  To: netdev
  Cc: Willem de Bruijn, David S . Miller, Eric Dumazet, Jakub Kicinski,
	Paolo Abeni, Simon Horman, Sebastian Andrzej Siewior,
	Clark Williams, Steven Rostedt, John Ogness, linux-kernel,
	linux-rt-devel

This revision keeps asynchronous block retirement but removes completion-side
queue locking, the four-state enum, the eight-block publication budget and
the workqueue used in v1. Private copy accounting now lives in the existing
pgv allocation. Packet allocation and the existing retirement timer publish
ready blocks in order under their existing receive queue lock.

A preempted copier in a sealed block does not prevent capture into the next
available block. Copy completion only performs a release decrement. In the
absence of further traffic, publication may wait for a later timer callback;
there is no hard bound under RT starvation. A finite ring can still exhaust.

Patch 1 independently moves virtio RX-header preparation ahead of frame
reservation. Patch 2 implements the retirement change. Neither patch changes
the mmap layout or adds a UAPI.

Changes since v1, in response to Willem de Bruijn:
- Split virtio header preparation into its own patch.
- Remove the second receive queue lock acquisition from copy completion.
- Remove the state enum, separate metadata allocation and worker lifecycle.
- Replace the fixed publication budget with a loop over existing ready blocks.
- Use release completion and acquire observation of per-block counts.
- Permit idle delivery to wait for the existing retirement timer.

Testing: ARM64 QEMU virt, four CPUs, PREEMPT_RT and lockdep. The unmodified
retirement logic blocks sender B behind a deliberately delayed copier A.
With v2, B completes capture before A is released, for full-block and timer
retirement; idle delivery, block sequence, lengths and payload are checked.
The delay is introduced by validation-only kernel instrumentation and is
not included in this series. Ordinary psock_tpacket and psock_fanout pass
on uninstrumented RT and non-RT builds. External validation tests exercise
the actual private helpers; LKMM tests check multi-copier ordering.

The ready-block loop has no fixed work budget: a large ready backlog can
lengthen the receive queue critical section. A validation case publishes
1000 blocks in one call. This tradeoff is explicitly retained for review.
Separate RT KASAN and strict KCSAN runs pass the helper checks, psock tests,
delayed-copy tests and concurrent-close test without sanitizer reports.
Patch 1 also passes an independent malformed-GSO runtime check. ARM64 W=1
packet-object builds pass for each patch and under allyesconfig/allmodconfig.
QEMU does not establish hardware NIC or Orin integration acceptance.

v1:
https://lore.kernel.org/netdev/20261028070528.139531-1-jingxuanxie@deeproute.ai/

Review:
https://lore.kernel.org/netdev/willemdebruijn.kernel.31ae9fde05c@gmail.com/

Base: fcc00b15cb21a6de76826e5012b2c758505f5e65 (net/main).

jingxuanxie (2):
  af_packet: prepare the virtio header before reserving an RX frame
  af_packet: retire TPACKET_V3 blocks without waiting for copiers

 net/packet/af_packet.c | 162 +++++++++++++++++++++----------------------
 net/packet/internal.h  |   9 ++-
 2 files changed, 88 insertions(+), 83 deletions(-)


base-commit: fcc00b15cb21a6de76826e5012b2c758505f5e65
--
2.25.1

________________________________


本电子邮件及转载的任何文件都属绝密文件，并且仅供标明地址的个人或团体使用。如果您收到的电子邮件存在错误，请通知本公司，删除全部原始信息（包括任何原始信息的备份），并且禁止散布或分发全部或部分原始信息。本公司不担保本电子邮件中信息的准确性、适当性或完整性，并且对此产生的任何错误或疏忽不承担任何责任。在正式协议签订以前，这里提到的任何参考术语、与主题相关的情形以及随后的电子邮件中的谈判，都将严格“遵守合同”。接收方应在接收电子邮件或任何附件时检查有无病毒，本公司对由于转载本电子邮件而引发病毒产生的任何损坏不承担任何责任。


Reproduced in this e-mail and any files are considered top-secret documents, and only indicate the address of individuals or groups. If you receive an e-mail there is an error, please notify the Company, delete all the original information (including any backup of the original information), and the prohibition of the dissemination or distribution of all or part of the original information. The Company does not guarantee the accuracy of the information in this e-mail, adequacy, or completeness, and this produces any error or omission does not bear any responsibility. The formal agreement was signed prior to any reference to the term mentioned here, and the circumstances relevant to the subject and subsequent e-mail in the negotiations will be strictly "comply with the contract." The receiver should be receiving an e-mail or any attachment, check for viruses. The company reproduced this e-mail because of the virus caused any damage resulting from not bear any responsibility.

^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2026-10-31  8:17 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2026-10-30  8:17 [RFC net v2 0/2] af_packet: retire TPACKET_V3 blocks without waiting for copiers Jingxuan Xie
2026-10-30  8:17 ` [RFC net v2 1/2] af_packet: prepare the virtio header before reserving an RX frame Jingxuan Xie
2026-10-30 17:21   ` Willem de Bruijn
2026-10-30  8:17 ` [RFC net v2 2/2] af_packet: retire TPACKET_V3 blocks without waiting for copiers Jingxuan Xie
2026-10-31  8:17   ` sashiko-bot
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2026-10-30  8:14 [RFC net v2 0/2] " Jingxuan Xie
2026-10-30  8:14 ` [RFC net v2 1/2] af_packet: prepare the virtio header before reserving an RX frame Jingxuan Xie

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