Re: [PATCH net] net: dev: Detect dev_hold() after netdev_wait_allrefs()

[Jann Horn]

On Fri, Jan 28, 2022 at 3:53 AM Eric Dumazet <edumazet@xxxxxxxxxx> wrote:
> On Thu, Jan 27, 2022 at 6:48 PM Jann Horn <jannh@xxxxxxxxxx> wrote:
>
> > When someone is using NET_DEV_REFCNT_TRACKER for slow debugging, they
> > should also be able to take the performance hit of
> > CONFIG_PCPU_DEV_REFCNT and rely on the normal increment-from-zero
> > detection of the generic refcount code, right? (Maybe
> > NET_DEV_REFCNT_TRACKER should depend on !CONFIG_PCPU_DEV_REFCNT?)
>
> NET_DEV_REFCNT_TRACKER is not slow, I think it has neglectable cost really.
> (I could not see any difference in my tests)

Ah, sorry. I misread the Kconfig text.