P3041DS,P2041DS: memory issue

P3041DS,P2041DS: memory issue

[Siva Borra]

Hello,

When I have enabled PREEMPT_RT_FULL on kernel, and see that the 
/proc/meminfo shows
only 660 MB of RAM, where as physical RAM that is attached is 4GB.

CONFIG_PREEMPT_RT_FULL=y
CONFIG_HZ_1000=y
CONFIG_HZ=1000

the meminfo reported 4GB when in normal case.  This is seen on both 
P3041Ds and P2041DS.
How to fix this issue?

Regards,
Siva Borra.

Re: P3041DS,P2041DS: memory issue

[Luo Zhenhua]

config HIGHMEM
        bool "High memory support"
        depends on PPC32 && !PREEMPT_RT_FULL

The highly helpful commit message of the patch that does this is:

    power-disable-highmem-on-rt.patch

    Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

Some vague details here:
https://bugzilla.yoctoproject.org/show_bug.cgi?id=6377

Looking at the x86 code, the fix appears to be the addition of 
current->kmap_pte[] bookkeeping, and switch_kmaps() on context switch.


Best Regards,

Zhenhua

> -----Original Message-----
> From: meta-freescale-bounces@yoctoproject.org [mailto:meta-freescale-
> bounces@yoctoproject.org] On Behalf Of Siva Borra
> Sent: Wednesday, June 03, 2015 7:01 PM
> To: meta-freescale@yoctoproject.org
> Cc: Adrian Dudau
> Subject: [meta-freescale] P3041DS,P2041DS: memory issue
> 
> Hello,
> 
> When I have enabled PREEMPT_RT_FULL on kernel, and see that the
> /proc/meminfo shows only 660 MB of RAM, where as physical RAM that is
> attached is 4GB.
> 
> CONFIG_PREEMPT_RT_FULL=y
> CONFIG_HZ_1000=y
> CONFIG_HZ=1000
> 
> the meminfo reported 4GB when in normal case.  This is seen on both P3041Ds
> and P2041DS.
> How to fix this issue?
> 
> Regards,
> Siva Borra.
> 
> --
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