Messages in this thread | | | Date | Wed, 23 Nov 2022 16:59:29 +0100 | From | Frederic Weisbecker <> | Subject | Re: [PATCH v2 rcu 05/16] rcu: Refactor code a bit in rcu_nocb_do_flush_bypass() |
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On Mon, Nov 21, 2022 at 05:04:10PM -0800, Paul E. McKenney wrote: > From: "Joel Fernandes (Google)" <joel@joelfernandes.org> > > This consolidates the code a bit and makes it cleaner. Functionally it > is the same. > > Reported-by: Paul E. McKenney <paulmck@kernel.org> > Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org> > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > --- > kernel/rcu/tree_nocb.h | 17 +++++++++-------- > 1 file changed, 9 insertions(+), 8 deletions(-) > > diff --git a/kernel/rcu/tree_nocb.h b/kernel/rcu/tree_nocb.h > index d6e4c076b0515..213daf81c057f 100644 > --- a/kernel/rcu/tree_nocb.h > +++ b/kernel/rcu/tree_nocb.h > @@ -327,10 +327,11 @@ static void wake_nocb_gp_defer(struct rcu_data *rdp, int waketype, > * > * Note that this function always returns true if rhp is NULL. > */ > -static bool rcu_nocb_do_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp, > +static bool rcu_nocb_do_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp_in, > unsigned long j, bool lazy) > { > struct rcu_cblist rcl; > + struct rcu_head *rhp = rhp_in;
Why that intermediate rhp_in?
> > WARN_ON_ONCE(!rcu_rdp_is_offloaded(rdp)); > rcu_lockdep_assert_cblist_protected(rdp); > @@ -345,16 +346,16 @@ static bool rcu_nocb_do_flush_bypass(struct rcu_data *rdp, struct rcu_head *rhp, > > /* > * If the new CB requested was a lazy one, queue it onto the main > - * ->cblist so we can take advantage of a sooner grade period. > + * ->cblist so that we can take advantage of the grace-period that will > + * happen regardless. But queue it onto the bypass list first so that > + * the lazy CB is ordered with the existing CBs in the bypass list. > */ > if (lazy && rhp) { > - rcu_cblist_flush_enqueue(&rcl, &rdp->nocb_bypass, NULL); > - rcu_cblist_enqueue(&rcl, rhp); > - WRITE_ONCE(rdp->lazy_len, 0); > - } else { > - rcu_cblist_flush_enqueue(&rcl, &rdp->nocb_bypass, rhp); > - WRITE_ONCE(rdp->lazy_len, 0); > + rcu_cblist_enqueue(&rdp->nocb_bypass, rhp); > + rhp = NULL; > } > + rcu_cblist_flush_enqueue(&rcl, &rdp->nocb_bypass, rhp); > + WRITE_ONCE(rdp->lazy_len, 0);
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Thanks.
> > rcu_segcblist_insert_pend_cbs(&rdp->cblist, &rcl); > WRITE_ONCE(rdp->nocb_bypass_first, j); > -- > 2.31.1.189.g2e36527f23 >
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