Hi Mark, >>If you are seeing issues with the current stack size, can you please >>explain that in more detail? Where are you seeing problems? Which >>configuration options do you have selected? >> We checked on our system with netflix and youtube 4K videos running max stack consumption was 7 KB: sh-3.2# cat /sys/kernel/debug/tracing/stack_max_size 7312 Thus we thought 16KB wil waste a lot of memory for our ARM64 target, and 8KB can be less in some exceptional case. So we decided for 12 KB change. >>I'm not keen on making kernel stack sizes configurable as it's not >>currently possible for the person building the kernel to figure out a >>safe size (and if this were possible, it's be better to handle this >>automatically). >> Ok, can we do something else?, like not making it configurable, but do code changes to support it for PAGE_SIZE aligned stacks rather than power of 2 alignement. Although with configurable also, it depends on VMAP stack, so user will have stack exhaust exception and can increase acccordingly also. > >Motivation behind these changes is saving memory on our system. >Our system runs around 2500 threads concurrently so saving 4Kb >might help us in saving 10MB memory. > >To ensure 12KB is sufficient for our system we have used stack tracing and >realised maximum stack used is not more than 9KB. > /sys/kernel/tracing/stack_max_size > >Tracing interface defined by kernel to track maximum stack size can be used >by others to decide appropriate stack size. > Thanks
