lkml.org 
[lkml]   [2015]   [Sep]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC PATCH 0/3] Implement IRQ stack on ARM64
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




\
 
 \ /
  Last update: 2015-09-07 16:41    [W:0.118 / U:0.692 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site