On Sun, Mar 3, 2013 at 2:51 PM, Al Viro <v...@zeniv.linux.org.uk> wrote:
>
> +struct vfree_deferred {
> + spinlock_t lock;
> + void *list;
> + struct work_struct wq;
> +};
Looking more at this, just get rid of the spinlock entirely, and use
<linux/llist.h> for the list.
IRQ-safety without the locking. Because you got the locking wrong
again, and made free_work() use spin_lock_irq(), but
> +static inline void deferred_vfree(void *addr)
> +{
> + struct vfree_deferred *p = &get_cpu_var(vfree_deferred);
> + spin_lock(&p->lock);
This needs to be a spin_lock_irqsave() too.
> + *(void **)addr = p->list;
> + p->list = addr;
> + schedule_work(&p->wq);
> + spin_unlock(&p->lock);
> + put_cpu_var(vfree_deferred);
And there is no reason to hold the lock - or even stay on the CPU -
over the work-scheduling (which had better be irq- and smp-safe on its
own anyway), so you're actually best off just using
struct vfree_deferred *p = &__get_cpu_var(vfree_deferred);
struct llist_node *new = (void *)addr;
llist_add(new, &p->list);
schedule_work(&p->wq);
and you're done.
I'm not even sure it's worth it making it per-cpu, but I guess it
won't hurt either.
Linus
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
