On 07/09/15 16:48, Jungseok Lee wrote: > On Sep 7, 2015, at 11:36 PM, James Morse wrote: > > Hi James, > >> Having to handle interrupts on top of an existing kernel stack means the >> kernel stack must be large enough to accomodate both the maximum kernel >> usage, and the maximum irq handler usage. Switching to a different stack >> when processing irqs allows us to make the stack size smaller. >> >> Maximum kernel stack usage (running ltp and generating usb+ethernet >> interrupts) was 7256 bytes. With this patch, the same workload gives >> a maximum stack usage of 5816 bytes. > > I'd like to know how to measure the max stack depth. > AFAIK, a stack tracer on ftrace does not work well. Did you dump a stack > region and find or track down an untouched region?
I enabled the 'Trace max stack' option under menuconfig 'Kernel Hacking' -> 'Tracers', then looked in debugfs:/tracing/stack_max_size. What problems did you encounter? (I may be missing something...) Thanks, James -- 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/