On Fri, Aug 08, 2025 at 05:12:04PM -0700, Jakub Kicinski wrote:
We chose not to have an "unset" state for threaded, and not to wipe the NAPI config clean when channels are explicitly disabled.
Yea... I wonder if we could change that now or if it's too late? I think this is the thing you mentioned that I couldn't recall in my response to the cover letter.
This means the persistent config structs "exist" even when their NAPIs are not instantiated.
Differently put - the NAPI persistent state lives in the net_device (ncfg == struct napi_config):
,--- [napi 0] - [napi 1][dev] | | `--- [ncfg 0] - [ncfg 1]
so say we a device with 2 queues but only 1 enabled:
,--- [napi 0][dev] | `--- [ncfg 0] - [ncfg 1]
now we set the device to threaded=1:
,---------- [napi 0 (thr:1)][dev(thr:1)] | `---------- [ncfg 0 (thr:1)] - [ncfg 1 (thr:?)]
Since [ncfg 1] was not attached to a NAPI during configuration we skipped it. If we create a NAPI for it later it will have the old setting (presumably disabled). One could argue if this is right or not "in principle", but it's definitely not how things worked before per-NAPI config..
Thanks for the detailed commit message. I agree that it should probably work the same now.
Fixes: 2677010e7793 ("Add support to set NAPI threaded for individual NAPI") Signed-off-by: Jakub Kicinski kuba@kernel.org
v2: add missing kdoc
include/linux/netdevice.h | 5 ++++- net/core/dev.c | 7 ++++++- 2 files changed, 10 insertions(+), 2 deletions(-)
Reviewed-by: Joe Damato joe@dama.to