Re: [PATCH] net: Handle threadirqs in __napi_schedule_irqoff

[Brett Creeley]

On 9/13/2024 8:23 AM, Sean Anderson wrote:
> Caution: This message originated from an External Source. Use proper caution when opening attachments, clicking links, or responding.
>
>
> On 9/13/24 11:16, Eric Dumazet wrote:
> > On Fri, Sep 13, 2024 at 5:10 PM Sean Anderson <sean.anderson@xxxxxxxxx> wrote:
> > > The threadirqs kernel parameter can be used to force threaded IRQs even
> > > on non-PREEMPT_RT kernels. Use force_irqthreads to determine if we can
> > > skip disabling local interrupts. This defaults to false on regular
> > > kernels, and is always true on PREEMPT_RT kernels.
> > >
> > > Signed-off-by: Sean Anderson <sean.anderson@xxxxxxxxx>
> > > ---
> > >
> > >   net/core/dev.c | 2 +-
> > >   1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/net/core/dev.c b/net/core/dev.c
> > > index 1e740faf9e78..112e871bc2b0 100644
> > > --- a/net/core/dev.c
> > > +++ b/net/core/dev.c
> > > @@ -6202,7 +6202,7 @@ EXPORT_SYMBOL(napi_schedule_prep);
> > >    */
> > >   void __napi_schedule_irqoff(struct napi_struct *n)
> > >   {
> > > -       if (!IS_ENABLED(CONFIG_PREEMPT_RT))
> > > +       if (!force_irqthreads())
> > >                  ____napi_schedule(this_cpu_ptr(&softnet_data), n);
> > >          else
> > >                  __napi_schedule(n);
> > > --
> > > 2.35.1.1320.gc452695387.dirty
> >
> > Seems reasonable, can you update the comment (kdoc) as well ?
> >
> > It says :
> >
> >   * On PREEMPT_RT enabled kernels this maps to __napi_schedule()
> >   * because the interrupt disabled assumption might not be true
> >   * due to force-threaded interrupts and spinlock substitution.
>
> OK
>
> > Also always specify net or net-next for networking patches.
>
> Ah, sorry. Should be net-next.

Is this worthy for a fixes/net tag?

Thanks,

Brett
> --Sean