On Mon, Oct 26, 2020 at 12:24:45PM +0100, Frederic Weisbecker wrote:
[..]
> > diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
> > index 0f23d20d485a..79b7081143a7 100644
> > --- a/kernel/rcu/srcutree.c
> > +++ b/kernel/rcu/srcutree.c
> > @@ -1160,6 +1160,7 @@ static void srcu_advance_state(struct srcu_struct
> > *ssp)
> > */
> > static void srcu_invoke_callbacks(struct work_struct *work)
> > {
> > + long len;
> > bool more;
> > struct rcu_cblist ready_cbs;
> > struct rcu_head *rhp;
> > @@ -1182,6 +1183,7 @@ static void srcu_invoke_callbacks(struct work_struct
> > *work)
> > /* We are on the job! Extract and invoke ready callbacks. */
> > sdp->srcu_cblist_invoking = true;
> > rcu_segcblist_extract_done_cbs(&sdp->srcu_cblist, &ready_cbs);
> > + len = ready_cbs.len;
> > spin_unlock_irq_rcu_node(sdp);
> > rhp = rcu_cblist_dequeue(&ready_cbs);
> > for (; rhp != NULL; rhp = rcu_cblist_dequeue(&ready_cbs)) {
> > @@ -1190,13 +1192,14 @@ static void srcu_invoke_callbacks(struct
> > work_struct *work)
> > rhp->func(rhp);
> > local_bh_enable();
> > }
> > + WARN_ON_ONCE(ready_cbs.len);
> >
> > /*
> > * Update counts, accelerate new callbacks, and if needed,
> > * schedule another round of callback invocation.
> > */
> > spin_lock_irq_rcu_node(sdp);
> > - rcu_segcblist_insert_count(&sdp->srcu_cblist, &ready_cbs);
> > + rcu_segcblist_add_len(&sdp->srcu_cblist, -len);
> > (void)rcu_segcblist_accelerate(&sdp->srcu_cblist,
> > rcu_seq_snap(&ssp->srcu_gp_seq));
> > sdp->srcu_cblist_invoking = false;
>
> Looks good! Thanks.
Just to report, with this fix the (s)rcutorture tests pass:
SRCU-N ------- 259086 GPs (143.937/s) [srcu: g3342384 f0x0 total-gps=3342384]
SRCU-P ------- 69443 GPs (38.5794/s) [srcud: g637552 f0x0 total-gps=637552]
thanks,
- Joel
