On Sat, Dec 10, 2011 at 11:52:51AM -0800, Andi Kleen wrote: > Dave Chinner <david@xxxxxxxxxxxxx> writes: > > > > You forgot about interrupt stacking - that trace shows the system > > took an interrupt at the point of highest stack usage in the > > writeback call chain.... :/ > > The interrupts are always running on other stacks these days > (even 32bit got switched over). Where does the x86-64 do the interrupt stack switch? I know the x86 32 bit interrupt handler switches to an irq/softirq context stack, but the 64 bit one doesn't appear to. Indeed, arch/x86/kernel/irq_{32,64}.c are very different, and only the 32 bit irq handler switches to another stack to process the interrupts... Cheers, Dave. -- Dave Chinner david@xxxxxxxxxxxxx -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx"> email@xxxxxxxxx </a>