Re: 2G memory split

[Mark Lord <lkml@rtr.ca>]

Kirill Korotaev wrote:
> > > +#if defined(CONFIG_DEFAULT_3G)
> > > +#define __PAGE_OFFSET_RAW    (0xC0000000)
> > > +#elif defined(CONFIG_DEFAULT_3G_OPT)
> > > +#define    __PAGE_OFFSET_RAW    (0xB0000000)
> > > +#elif defined(CONFIG_DEFAULT_2G)
> > > +#define __PAGE_OFFSET_RAW    (0x78000000)
> > > +#elif defined(CONFIG_DEFAULT_1G)
> > > +#define __PAGE_OFFSET_RAW    (0x40000000)
> > > +#else
> > > +#error "Bad user/kernel offset"
> > > +#endif
> > > +
> > >  #ifdef __ASSEMBLY__
> > > -#define __PAGE_OFFSET        (0xC0000000)
> > > +#define __PAGE_OFFSET        __PAGE_OFFSET_RAW
> > >  #define __PHYSICAL_START    CONFIG_PHYSICAL_START
> > >  #else
> > > -#define __PAGE_OFFSET        (0xC0000000UL)
> > > +#define __PAGE_OFFSET        ((unsigned long)__PAGE_OFFSET_RAW)
> > >  #define __PHYSICAL_START    ((unsigned long)CONFIG_PHYSICAL_START)
> > >  #endif
> > >  #define __KERNEL_START        (__PAGE_OFFSET + __PHYSICAL_START)
> >
> > Changing PAGE_OFFSET this way would break at least Valgrind (the latest
> > release 3.1.0 by default is statically linked at address 0xb0000000, and
> > PIE support does not seem to be present in that release).  I remember
> > that similar changes were also breaking Lisp implementations (cmucl,
> > sbcl), however, I am not really sure about this.
> it also breaks some java versions, so we use 3:4 Gb split in OpenVZ, but 
> redhat still uses 4:4 in enterprise version, so number of such 
> applications should decrease :)

Mmm.. that's an old thread.  The reply above was to
a posting from Sergey Vlasov (the same) on Tue Jan 10 2006,
12:06:50 EST.
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