On 04/09/15 15:23, Jungseok Lee wrote: > ARM64 kernel allocates 16KB kernel stack when creating a process. In case > of low memory platforms with tough workloads on userland, this order-2 > allocation request reaches to memory pressure and performance degradation > simultaenously since VM page allocator falls into slowpath frequently, > which triggers page reclaim and compaction. > > I believe that one of the best solutions is to reduce kernel stack size. > According to the following data from stack tracer with some fixes, [1], > a separate IRQ stack would greatly help to decrease a kernel stack depth. >
Hi Jungseok Lee, I was working on a similar patch for irq stack, (patch as a follow up email). I suggest we work together on a single implementation. I think the only major difference is that you're using sp_el0 as a temporary register to store a copy of the stack-pointer to find struct thread_info, whereas I was copying it between stacks (ends up as 2x ldp/stps), which keeps the change restricted to irq_stack setup code. We should get some feedback as to which approach is preferred. Thanks, James Morse -- 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/