On Tue, Sep 08, 2020 at 10:35:22PM +0100, Edward Cree wrote:
On 08/09/2020 16:25, Greg Kroah-Hartman wrote:
From: Alexander Lobakin alobakin@dlink.ru
commit 6570bc79c0dfff0f228b7afd2de720fb4e84d61d upstream.
Commit 323ebb61e32b4 ("net: use listified RX for handling GRO_NORMAL skbs") made use of listified skb processing for the users of napi_gro_frags(). The same technique can be used in a way more common napi_gro_receive() to speed up non-merged (GRO_NORMAL) skbs for a wide range of drivers including gro_cells and mac80211 users. This slightly changes the return value in cases where skb is being dropped by the core stack, but it seems to have no impact on related drivers' functionality. gro_normal_batch is left untouched as it's very individual for every single system configuration and might be tuned in manual order to achieve an optimal performance.
Signed-off-by: Alexander Lobakin alobakin@dlink.ru Acked-by: Edward Cree ecree@solarflare.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Hyunsoon Kim h10.kim@samsung.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
I'm not quite sure why this is stable material(it's a performance enhancement, rather than a fix). But if you do want to take it, make sure you've also got c80794323e82 ("net: Fix packet reordering caused by GRO and listified RX cooperation") b167191e2a85 ("net: wireless: intel: iwlwifi: fix GRO_NORMAL packet stalling") in your tree, particularly the latter as without it this commit triggers a severe regression in iwlwifi.
Hm, that feels bad, I'll go drop this for now.
Hyunsoon was the one who asked for this, so I will let them defend the request. I thought they were asking for this because it was a bug fix, but if it is a performance issue, that's fine as long as it doesn't also cause problems :)
Hyunsoon, should all of these be taken, and if so, what exactly is the performance increase here?
thanks,
greg k-h