v3.16-rc1 & default cachepolicy

[Aaro Koskinen]

Hi,

When booting v3.16-rc1 on OMAP1, I noticed strange slowness.
E.g. initramfs unpack takes several minutes. This was caused by default
cachepolicy getting changed from writethrough -> uncached for some reason:

[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] Initializing cgroup subsys cpu
[    0.000000] Linux version 3.16.0-rc1-e3-los_880e+ (aaro at cooljazz) (gcc version 4.9.0 (GCC) ) #1 PREEMPT Thu Jun 19 22:51:42 EEST 2014
[    0.000000] CPU: ARM925T [54029252] revision 2 (ARMv4T), cr=0000317f
[    0.000000] CPU: VIVT data cache, VIVT instruction cache
[    0.000000] Machine: Amstrad E3 (Delta)
[    0.000000] Ignoring memory below PHYS_OFFSET: 0x02000000-0x10000000
[    0.000000] bootconsole [earlycon0] enabled
[    0.000000] Memory policy: Data cache uncached
[...]
[    4.602732] Unpacking initramfs...
[  425.125093] Freeing initrd memory: 3532K (c1c00000 - c1f73000)

It seems this is caused by commit:

commit ca8f0b0a545f55b3dc6877cda24d609a8979c951
Author: Russell King <rmk+kernel at arm.linux.org.uk>
Date:   Tue May 27 20:34:28 2014 +0100

    ARM: ensure C page table setup code follows assembly code

I can workaround this with "cachepolicy=writethrough" parameter.

A.