Messages in this thread Patch in this message | | | Date | Wed, 12 Oct 2022 01:10:53 +0200 | From | Frederic Weisbecker <> | Subject | Re: [PATCH v8 02/13] rcu: Make call_rcu() lazy to save power |
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On Tue, Oct 11, 2022 at 06:01:31PM +0000, Joel Fernandes (Google) wrote: > @@ -269,10 +294,14 @@ static void wake_nocb_gp_defer(struct rcu_data *rdp, int waketype, > raw_spin_lock_irqsave(&rdp_gp->nocb_gp_lock, flags); > > /* > - * Bypass wakeup overrides previous deferments. In case > - * of callback storm, no need to wake up too early. > + * Bypass wakeup overrides previous deferments. In case of > + * callback storm, no need to wake up too early. > */ > - if (waketype == RCU_NOCB_WAKE_BYPASS) { > + if (waketype == RCU_NOCB_WAKE_LAZY && > + READ_ONCE(rdp->nocb_defer_wakeup) == RCU_NOCB_WAKE_NOT) {
No need for READ_ONCE() here.
> + mod_timer(&rdp_gp->nocb_timer, jiffies + jiffies_till_flush); > + WRITE_ONCE(rdp_gp->nocb_defer_wakeup, waketype); > + } else if (waketype == RCU_NOCB_WAKE_BYPASS) { > mod_timer(&rdp_gp->nocb_timer, jiffies + 2); > WRITE_ONCE(rdp_gp->nocb_defer_wakeup, waketype); > } else { > @@ -611,6 +682,8 @@ static void nocb_gp_wait(struct rcu_data *my_rdp) > unsigned long flags; > bool gotcbs = false; > unsigned long j = jiffies; > + bool lazy = false; > + long lazy_ncbs;
Looks like lazy_ncbs can be declared withing the loop, as well as bypass_cbs.
Anyway, apart from such boring cosmectics:
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Thanks!
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