On Mon, Oct 14, 2024 at 11:12:29AM +0800, Xuan Zhuo wrote:
> In the last linux version, we disabled this feature to fix the
> regress[1].
>
> The patch set is try to fix the problem and re-enable it.
>
> More info:
> http://lore.kernel.org/all/20240820071913.68004-1-xuanz...@linux.alibaba.com
>
Now, the premapped mode can be enabled unconditionally.
So we can remove the failover code for merge and small mode.
Signed-off-by: Xuan Zhuo
---
drivers/net/virtio_net.c | 80 +---
1 file changed, 33 insertions(+), 47 deletions(-)
diff --git a/drivers/net/v
Currently, the virtio core will perform a dma operation for each
buffer. Although, the same page may be operated multiple times.
In premapped mod, we can perform only one dma operation for the pages of
the alloc frag. This is beneficial for the iommu device.
kernel command line: intel_iommu=on io
Now, if we want to judge the rx work mode, we have to use such codes:
1. merge mode: vi->mergeable_rx_bufs
2. big mode: vi->big_packets && !vi->mergeable_rx_bufs
3. small: !vi->big_packets && !vi->mergeable_rx_bufs
This is inconvenient and abstract, and we also have this use case:
if (vi->
The virtio-net big mode did not enable premapped mode,
so we did not need to check the unmap. And the subsequent
commit will remove the failover code for failing enable
premapped for merge and small mode. So we need to remove
the checking do_dma code in the big mode path.
Signed-off-by: Xuan Zhuo
When the frag just got a page, then may lead to regression on VM.
Specially if the sysctl net.core.high_order_alloc_disable value is 1,
then the frag always get a page when do refill.
Which could see reliable crashes or scp failure (scp a file 100M in size
to VM):
The issue is that the virtnet_rq
In the last linux version, we disabled this feature to fix the
regress[1].
The patch set is try to fix the problem and re-enable it.
More info:
http://lore.kernel.org/all/20240820071913.68004-1-xuanz...@linux.alibaba.com
Thanks.
[1]: http://lore.kernel.org/all/8b20cc28-45a9-4643-8e87-ba164a540
