On Sep 7, 2015, at 11:33 PM, James Morse wrote: > 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,
Hi James Morse, > 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. Great idea! I'd really like to figure out the most ideal implementation of this feature. Best Regards Jungseok Lee-- 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/
