From: Tantilov, Emil S <emil.s.tanti...@intel.com> Date: Wed, 14 Feb 2024 07:39:53 -0800
> > > On 2/14/2024 6:54 AM, Alexander Lobakin wrote: >> From: Alexander Lobakin <aleksander.loba...@intel.com> >> Date: Tue, 13 Feb 2024 14:16:47 +0100 >> >>> From: Alan Brady <alan.br...@intel.com> >>> Date: Wed, 7 Feb 2024 16:42:43 -0800 >>> >>>> From: Emil Tantilov <emil.s.tanti...@intel.com> >>>> >>>> Fix softirq's not being handled during napi_schedule() call when >>>> receiving marker packets for queue disable by disabling local bottom >>>> half. >>> >>> BTW, how exactly does this help? >>> >>> __napi_schedule() already disables interrupts (local_irq_save()). >>> napi_schedule_prep() only has READ_ONCE() and other atomic read/write >>> helpers. >>> >>> It's always been safe to call napi_schedule() with enabled BH, so I >>> don't really understand how this works. > > It's been a while since I debugged this, I'll have to take a look again, > but its not so much about being safe as it is about making sure the > marker packets are received in those cases - like ifdown in the trace. > >> This also needs to be dropped from the fixes queue until investigated. >> For now, it looks like a cheap hack (without the explanation how exactly >> it does help), not a proper fix. > > It does fix the issue at hand. Looking at the kernel code I see multiple Sometimes adding debug prints fixes bugs, fixing something doesn't mean it's the correct way. > examples of napi_schedule() being wrapped with local_bh_disable/enable, "Everybody do that" doesn't prove anything until explained how exactly this helps. > so this appears to be a common (not uncommon?) technique. > > Thanks, > Emil > >> >> Thanks, >> Olek Thanks, Olek
