Re: [PATCH net v1] net: stmmac: set PP_FLAG_DMA_SYNC_DEV only if XDP is enabled

From: Paolo Abeni
Date: Thu Sep 19 2024 - 06:26:10 EST


On 9/13/24 13:02, Furong Xu wrote:
When XDP is not enabled, the page which holds the received buffer
will be recycled once the buffer is copied into SKB by
skb_copy_to_linear_data(), then the MAC core will never reuse this
page any longer. Set PP_FLAG_DMA_SYNC_DEV wastes CPU cycles.

This patch brings up to 9% noticeable performance improvement on
certain platforms.

Fixes: 5fabb01207a2 ("net: stmmac: Add initial XDP support")
Signed-off-by: Furong Xu <0x1207@xxxxxxxxx>

I'm quite unconvinced that every performance improvement would be eligible to be considered a fix.

Reading the code it looks like this change actually addresses a regression introduced by the blamed commit, is that correct? If so please re-phrase the commit message accordingly.

Thanks,

Paolo