Messages in this thread | | | Date | Mon, 07 Sep 2015 17:06:19 +0100 | From | James Morse <> | Subject | Re: [PATCH] arm64: kernel: Use a separate stack for irq interrupts. |
| |
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
| |