Re: [PATCH] arm: Update memblock limit after mapping lowmem

[Laura Abbott]

On 06/11/2015 06:07 AM, Mark Rutland wrote:
> On Thu, Jun 04, 2015 at 08:15:49PM +0100, Laura Abbott wrote:
> > The memblock limit is currently used in find_limits
> > to find the bounds for ZONE_NORMAL. The memblock
> > limit may need to be rounded down a PMD size to ensure
> > allocations are fully mapped though. This has the side
> > effect of reducing the amount of memory in ZONE_NORMAL.
> > Once all lowmem is mapped, it's safe to change the memblock
> > limit back to include the unaligned section. Adjust the
> > memblock limit after lowmem mapping is complete.
> >
> > Before:
> >   # cat /proc/zoneinfo | grep managed
> >          managed  62907
> >          managed  424
> >
> > After:
> >   # cat /proc/zoneinfo | grep managed
> >          managed  63331
> >
> > Signed-off-by: Laura Abbott <labbott@xxxxxxxxxxxxxxxxx>
> > ---
> > This is a replacement for
> > 'arm: Don't use memblock limit for the lowmem bound' which
> > doesn't actually work on NOMMU systems.
>
> Works for me on TC2, atop v4.1-rc7. Before this patch, with a few byes
> carved out of the memory node I would see:
>
> Memory: 1030380K/1046528K available (4832K kernel code, 154K rwdata, 1376K rodata, 260K init, 147K bss, 16148K reserved, 0K cma-reserved)
>
> $ cat /proc/zoneinfo | grep managed
>          managed  257660
>
> With the patch I see:
>
> Memory: 1032424K/1048572K available (4832K kernel code, 154K rwdata, 1376K rodata, 260K init, 147K bss, 16148K reserved, 0K cma-reserved)
>
> $ cat /proc/zoneinfo | grep managed
>          managed  258171
>
> The patch itself looks good to me.
>
> Reviewed-by: Mark Rutland <mark.rutland@xxxxxxx>
> Tested-by: Mark Rutland <mark.rutland@xxxxxxx>
>
> Thanks,
> Mark.

FYI, I put this in the patch tracker. I was on vacation when the Reviewed-by/Tested-by
came in so I'm only getting to it now.

Thanks,
Laura

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