speed process startup by 7%

[Jakub Jelinek]

On Wed, Jan 11, 2006 at 07:41:19AM -0800, John Reiser wrote:
> Jakub Jelinek wrote:
> > Prelink by default allocates libs on i?86 in the
> > 0x00101000 .. 0x00e00000
> > 0x02000000 .. 0x08000000
> > 0x41000000 .. 0x50000000
> > regions.  So, if kernel wants to put vDSO randomly into the ASCII zone,
> > it can have 528 choices (2MB from 0xe00000 to 0x1010000) or if it doesn't
> > care about that, it can use 18MB (0xe00000 to 0x2000000), i.e. 4608
> > possibile placements.
> > Of course it is possible to change prelink to pick up different
> > ranges (though, the 0 .. 1MB+4KB range is not an option due to various
> > emulators that need that range and from 0x08000000 or so start binaries
> > and if possible, prelink would like to use at least part of the ASCII zone).
> 
> It would be nice if prelink default policy avoided 0 .. 0x111000
> (1MB + 64KB + 4KB) so that vm86 could run various programs that
> use "himem" where the segment base is 0xffff0 (1MB - 16)
> and inclusive limit is 0xffff, which gives a highest address of
> 0x10ffef.  [It would have been nice if the default linux kernel
> loaded at 0x110000 instead of 0x100000.  Then Win3.1 and linux
> could have co-existed in memory.]

Just use LD_USE_LOAD_BIAS=0 in the environment of the emulator
to disregard prelink chosen addresses for it (similarly to how
the dynamic linker disregards prelink chosen addresses by default
for Position Independent Executables).

	Jakub