On Sat, 2008-02-09 at 10:01 -0800, Arjan van de Ven wrote: > > default n > > help > > This will build a kernel module called mmiotrace. > > + Making this a built-in is heavily discouraged. > > why is this? Wouldn't it be nice if distros just shipped with this in their > kernel by default > for example?
so default m? > > -#ifdef CONFIG_PAGE_FAULT_HANDLERS > > -static HLIST_HEAD(pf_handlers); /* protected by RCU */ > > -static DEFINE_SPINLOCK(pf_handlers_writer); > > +#ifdef CONFIG_MMIOTRACE_HOOKS > > +static pf_handler_func mmiotrace_pf_handler; /* protected by RCU */ > > +static DEFINE_SPINLOCK(mmiotrace_handler_lock); > > > > -void register_page_fault_handler(struct pf_handler *new_pfh) > > +int mmiotrace_register_pf(pf_handler_func new_pfh) > > { > > + int ret = 0; > > unsigned long flags; > > - spin_lock_irqsave(&pf_handlers_writer, flags); > > - hlist_add_head_rcu(&new_pfh->hlist, &pf_handlers); > > - spin_unlock_irqrestore(&pf_handlers_writer, flags); > > + spin_lock_irqsave(&mmiotrace_handler_lock, flags); > > + if (mmiotrace_pf_handler) > > + ret = -EBUSY; > > + else > > + mmiotrace_pf_handler = new_pfh; > > + spin_unlock_irqrestore(&mmiotrace_handler_lock, flags); > > + return ret; > > } > > -EXPORT_SYMBOL_GPL(register_page_fault_handler); > > +EXPORT_SYMBOL_GPL(mmiotrace_register_pf); > > why not use a weak function instead? should be a ton simpler. AFAIC weak functions are a built time thing, not fixed up on module load. So I'm not seeing the applicability there. Also, it would force a function call, even for the unlikely case the tracer is set. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/