On Fri, 16 Nov 2018 23:13:48 +0530, Pintu Agarwal said: > On Fri, Nov 16, 2018 at 10:16 PM wrote: > > Congrats. You just re-invented DEBUG_STACK_USAGE, which just keeps a high-water mark > > for stack usage. > > So, you mean to say, my implementation is good enough to get the > irq_stack usage, from the interrupt handler ? No - your code doesn't keep a high-water mark (which should probably be hooked into the IRQ exit code. > But my concern is that if I dump it from irq handler, I will get > information only for the current cpu. > How do I store and get the information for all the cpu from the boot time ? Make the high-water mark a per-cpu variable. > From where do I call my dump_irq_stack_info() [some where during the > entry/exit part of the irq handler], so that I could dump information > for all the handler at boot time itself ? No, you don't do a dump-stack during entry/exit. You just maintain a high-water value in the exit, and then you create a /proc/something or similar that when read does a 'foreach CPU do print_high_water_irq'. > Like I would to capture these information: > - What was the name of the handler ? > - Which cpu was executing it ? > - How much irq stack (max value, same like high water mark) were used > at that time ? First, do the easy part and find out if you even *care* once you see actual numbers. If your IRQ stack is 8K but you never use more than 2500 bytes, do you *really* care about the name of the handler anymore? Also, see the code for /proc/interrupts to see how it keeps track of the interrupts per CPU - maybe all you need to do is change each entry from a 'count' to 'count, highwater'.