On 02/17, Paul E. McKenney wrote: > > On Tue, Feb 17, 2009 at 08:28:10PM +0100, Oleg Nesterov wrote: > > > > So the question is: is there any arch which surely needs this barrier? > > > > IOW, > > int COND; > > > > void smp_xxx_interrupt(regs) > > { > > BUG_ON(!COND); > > } > > > > COND = 1; > > mb(); > > smp_send_xxx(cpu); > > > > can we really hit the BUG_ON() above on some arch? > > If all of the above is executed by the same task, tripping the BUG_ON() > means either a compiler or CPU bug. I think you misunderstood... smp_send_xxx() sends the ipi to another CPU, and smp_xxx_interrupt() is the handler. Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html