Finding kernel RAM consumers ?

[Matthew Wilcox]

On Fri, Jun 03, 2022 at 05:26:33PM +0000, Joakim Tjernlund wrote:
> On Fri, 2022-06-03 at 08:49 +0200, Joakim Tjernlund wrote:
> > On Thu, 2022-06-02 at 21:11 +0100, Matthew Wilcox wrote:
> > > On Thu, Jun 02, 2022 at 07:24:23PM +0000, Joakim Tjernlund wrote:
> > > > We have this small embedded target(aarch64) with 32 MB of RAM where the kernel consumes 14420K:
> > > > Memory: 22444K/36864K available (3584K kernel code, 698K rwdata, 936K rodata, 320K init, 255K bss, 14420K reserved, 0K cma-reserved)
> > > > 
> > > > I want to track down were most of this RAM is consumed so I can trim away some MBs
> > > > but I am having a hard time finding may way.
> > > > Is there some tool/kernel config that can help me with that?
> > 
> > Those are interesting, thanks.
> > In my case it is the amount of work space RAM allocated that is a bit much. The kernel code/data
> > is 5+MB but the total need is 14MB, 9MB is buffer and similar.
> > 
> >  Jocke
> 
> Found something, arm64 only supports mem model SPARSEMEM_EXTREME and it uses most of my memory.
> Tried to force SPARSEMEM_STATIC but that didn't boot, is STATIC even cheaper ? 
That sounds like a question for the arm64 maintainers