On 02/18, Ingo Molnar wrote: > > Based on an idea from Stephen Hemminger: introduce > mod_timer_pending() which is a mod_timer() offspring > that is an invariant on already removed timers. This also can be used by workqueues, see http://marc.info/?l=linux-kernel&m=122209752020413 but can't we add another helper? Because, > +static inline int > +__mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only) > { > struct tvec_base *base, *new_base; > unsigned long flags; > - int ret = 0; > + int ret; > + > + ret = 0; > > timer_stats_timer_set_start_info(timer); > BUG_ON(!timer->function); > @@ -614,6 +617,9 @@ int __mod_timer(struct timer_list *timer > if (timer_pending(timer)) { > detach_timer(timer, 0); > ret = 1; > + } else { > + if (pending_only) > + goto out_unlock; This can change the base (CPU) of the pending timer. How about int __update_timer(struct timer_list *timer, unsigned long expires) { struct tvec_base *base; unsigned long flags; int ret = 0; base = lock_timer_base(timer, &flags); if (timer_pending(timer)) { detach_timer(timer, 0); timer->expires = expires; internal_add_timer(base, timer); ret = 1; } spin_unlock_irqrestore(&base->lock, flags); return ret; } ? Unlike __mod_timer(..., bool pending_only), it preserves the CPU on which the timer is pending. Or, perhaps, we can modify __mod_timer() further, static inline int __mod_timer(struct timer_list *timer, unsigned long expires, bool pending_only) { struct tvec_base *base; unsigned long flags; int ret; ret = 0; timer_stats_timer_set_start_info(timer); BUG_ON(!timer->function); base = lock_timer_base(timer, &flags); if (timer_pending(timer)) { detach_timer(timer, 0); ret = 1; } else if (pending_only) goto out_unlock; } debug_timer_activate(timer); if (!pending_only) { struct tvec_base *new_base = __get_cpu_var(tvec_bases); if (base != new_base) { /* * We are trying to schedule the timer on the local CPU. * However we can't change timer's base while it is running, * otherwise del_timer_sync() can't detect that the timer's * handler yet has not finished. This also guarantees that * the timer is serialized wrt itself. */ if (likely(base->running_timer != timer)) { /* See the comment in lock_timer_base() */ timer_set_base(timer, NULL); spin_unlock(&base->lock); base = new_base; spin_lock(&base->lock); timer_set_base(timer, base); } } } timer->expires = expires; internal_add_timer(base, timer); out_unlock: spin_unlock_irqrestore(&base->lock, flags); return ret; } What do you all think? Oleg. -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
