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Date: Wed, 20 Aug 2008 16:41:51 -0700
From: Nathan Whitehorn <nwhitehorn@freebsd.org>
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To: John Baldwin <jhb@freebsd.org>
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Cc: freebsd-arch@freebsd.org
Subject: Re: UMA MD Small Allocator Runtime Switching
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John Baldwin wrote:
> [snip]
>> I thought about it, but we can only use 4K pages on the G5 so this would 
>> put a large amount of pressure on the page table. IBM removed the block 
>> translation mechanism from the G5 and the CPU's superpage support is not 
>> available in the 32-bit compatibility mode under which we currently run.
>>     
>
> Hmm, I didn't know you weren't running in full 64-bit mode.  Is that a 
> property of the G5 CPU that it only supports the 32-bit compat mode with 
> 64-bit extensions?
>   
(see other email about the properties of the G5)

I think the following one-line patch provides a reasonable solution to 
this problem. Is there any reason this is a bad idea?
-Nathan

Index: uma_core.c
===================================================================
--- uma_core.c  (revision 181929)
+++ uma_core.c  (working copy)
@@ -1667,7 +1667,7 @@
 
        bucket_init();
 
-#ifdef UMA_MD_SMALL_ALLOC
+#if defined(UMA_MD_SMALL_ALLOC) && !defined(UMA_MD_SMALL_ALLOC_NEEDS_VM)
        booted = 1;
 #endif