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author | Laurent Vivier <lvivier@redhat.com> | 2025-05-21 11:22:36 +0200 |
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committer | Paolo Abeni <pabeni@redhat.com> | 2025-07-03 11:40:02 +0200 |
commit | 24b2f5df86aaebbe7bac40304eaf5a146c02367c (patch) | |
tree | 27c56a662c6e7a5530d251c88cfec275738b98d6 /scripts/lib/kdoc/kdoc_files.py | |
parent | bd2948d2581ebd31745c1b7094a470513789555f (diff) |
virtio_net: Enforce minimum TX ring size for reliability
The `tx_may_stop()` logic stops TX queues if free descriptors
(`sq->vq->num_free`) fall below the threshold of (`MAX_SKB_FRAGS` + 2).
If the total ring size (`ring_num`) is not strictly greater than this
value, queues can become persistently stopped or stop after minimal
use, severely degrading performance.
A single sk_buff transmission typically requires descriptors for:
- The virtio_net_hdr (1 descriptor)
- The sk_buff's linear data (head) (1 descriptor)
- Paged fragments (up to MAX_SKB_FRAGS descriptors)
This patch enforces that the TX ring size ('ring_num') must be strictly
greater than (MAX_SKB_FRAGS + 2). This ensures that the ring is
always large enough to hold at least one maximally-fragmented packet
plus at least one additional slot.
Reported-by: Lei Yang <leiyang@redhat.com>
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://patch.msgid.link/20250521092236.661410-4-lvivier@redhat.com
Tested-by: Lei Yang <leiyang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'scripts/lib/kdoc/kdoc_files.py')
0 files changed, 0 insertions, 0 deletions