Re: Patch to reorder functions in the vmlinux to a defined order

[Linus Torvalds <torvalds@osdl.org>]

On Thu, 23 Feb 2006, Arjan van de Ven wrote:
> > 
> > I think you would first need to move the code first for that. Currently it starts
> > at 1MB, which means 1MB is already wasted of the aligned 2MB TLB entry.
> > 
> > I wouldn't have a problem with moving the 64bit kernel to 2MB though.
> 
> that was easy since it's a Config entry already ;)

Btw, the "low TLB entry" for the direct-mapped case can't be used as a 
hugetlb page anyway, due to the MMU splitting it up due to the special 
MTRR regions, if I recall correctly.

So this is probably a bigger performance win than just the difference 
between using one or two TLB entries.

The same should be true on x86, btw. Where we should use a physical start 
address of 4MB for best performance.

Does anybody want to run benchmarks? (Totally untested, may not boot, 
might physically accost your pets for all I know).

		Linus

---
diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig
index 0afec85..d2b1df8 100644
--- a/arch/i386/Kconfig
+++ b/arch/i386/Kconfig
@@ -715,7 +715,7 @@ config PHYSICAL_START
 	hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP)
 
 	default "0x1000000" if CRASH_DUMP
-	default "0x100000"
+	default "0x400000"
 	help
 	  This gives the physical address where the kernel is loaded. Normally
 	  for regular kernels this value is 0x100000 (1MB). But in the case
-
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