Paul Menage wrote: > On Sun, Jun 15, 2008 at 6:32 PM, KOSAKI Motohiro > <kosaki.motohiro@xxxxxxxxxxxxxx> wrote: >> honestly, I used res_counter on early version. >> but I got bad performance. > > Bad performance on the charge/uncharge? > > The only difference I can see is that res_counter uses > spin_lock_irqsave()/spin_unlock_irqrestore(), and you're using plain > spin_lock()/spin_unlock(). > > Is the overhead of a pushf/cli/popf really going to matter compared > with the overhead of forking/exiting a task? > > Or approaching this from the other side, does res_counter really need > irq-safe locking, or is it just being cautious? We really need irq-safe locking. We can end up uncharging from reclaim context (called under zone->lru_lock and mem->zone->lru_lock - held with interrupts disabled) I am going to convert the spin lock to a reader writers lock, so that reads from user space do not cause contention. I'll experiment and look at the overhead. -- Warm Regards, Balbir Singh Linux Technology Center IBM, ISTL _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
