From: Cong Wang
> Sent: 20 October 2017 21:52
> To: Paul E. McKenney
> Cc: Jamal Hadi Salim; Chris Mi; Linux Kernel Network Developers; Daniel
> Borkmann; Eric Dumazet; David
> Miller; Jiri Pirko
> Subject: Re: Get rid of RCU callbacks in TC filters?
>
> On Fri, Oct 2
On Fri, Oct 20, 2017 at 1:31 PM, Cong Wang wrote:
> Actually, I just tried this approach, this way makes the core tc filter
> code harder to wait for flying callbacks, currently rcu_barrier() is
> enough, with one more schedule_work() added we probably
> need flush_workqueue()... Huh, this also me
On Fri, Oct 20, 2017 at 9:56 AM, Paul E. McKenney
wrote:
> On Thu, Oct 19, 2017 at 08:26:01PM -0700, Cong Wang wrote:
>> On Wed, Oct 18, 2017 at 12:35 PM, Paul E. McKenney
>> wrote:
>> > 5) Keep call_rcu(), but have the RCU callback schedule a workqueue.
>> > The workqueue could then use blocking
On Thu, Oct 19, 2017 at 08:26:01PM -0700, Cong Wang wrote:
> On Wed, Oct 18, 2017 at 12:35 PM, Paul E. McKenney
> wrote:
> > On Wed, Oct 18, 2017 at 10:36:28AM -0700, Cong Wang wrote:
> >> Hi, all
> >>
> >> Recently, the RCU callbacks used in TC filters and TC actions keep
> >> drawing my attentio
On Wed, Oct 18, 2017 at 12:35 PM, Paul E. McKenney
wrote:
> On Wed, Oct 18, 2017 at 10:36:28AM -0700, Cong Wang wrote:
>> Hi, all
>>
>> Recently, the RCU callbacks used in TC filters and TC actions keep
>> drawing my attention, they introduce at least 4 race condition bugs:
>>
>> 1. A simple one f
On Thu, Oct 19, 2017 at 8:34 AM, John Fastabend
wrote:
>
> My take on this would be to stay with the current RCU callbacks and try
> to simplify the implementation. Falling back to sync operations seems
> like a step backwards to me. I know update/delete of filters is currently
> a pain point for
On 10/18/2017 12:35 PM, Paul E. McKenney wrote:
> On Wed, Oct 18, 2017 at 10:36:28AM -0700, Cong Wang wrote:
>> Hi, all
>>
>> Recently, the RCU callbacks used in TC filters and TC actions keep
>> drawing my attention, they introduce at least 4 race condition bugs:
>>
>> 1. A simple one fixed by Dan
On Wed, Oct 18, 2017 at 10:36:28AM -0700, Cong Wang wrote:
> Hi, all
>
> Recently, the RCU callbacks used in TC filters and TC actions keep
> drawing my attention, they introduce at least 4 race condition bugs:
>
> 1. A simple one fixed by Daniel:
>
> commit c78e1746d3ad7d548bdf3fe491898cc453911