[haiku-bugs] Re: [Haiku] #5164: [boot_loader_openfirmware] panic: out of page table entries

#5164: [boot_loader_openfirmware] panic: out of page table entries
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 Reporter:  andreasf            |       Owner:  axeld         
     Type:  bug                 |      Status:  new           
 Priority:  normal              |   Milestone:                
Component:  System/Boot Loader  |     Version:  R1/Development
 Keywords:                      |   Blockedby:                
 Platform:  PowerPC             |    Blocking:                
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Comment(by bonefish):

 Replying to [comment:1 andreasf]:
 > Is this related to the amount of memory installed? (3 GB vs. 384 MB on
 my G3)

 Kind of.

 > Any constant I could tweak to fix or get past this issue?

 This is actually a design problem of the PPC architecture. The "PowerPC
 Operating Environment Architecture Book III" says:
 "This can happen if too many hash collisions occur and there are more than
 16 entries for the same primary/secondary pair of PTEGs. While this
 situation cannot be guaranteed not to occur for any size Page Table,
 making the Page Table larger than the minimum size (see Section 4.5.2)
 will reduce the frequency of occurrence of such collisions."

 According to the debug output the page table size is 32 MB, which is the
 suggested minimum for up to 4 GB RAM. You could try to increase it. In
 src/system/boot/platform/openfirmware/arch/ppc/mmu.cpp:arch_mmu_init()
 just multiply suggestedTableSize by 2.

-- 
Ticket URL: <http://dev.haiku-os.org/ticket/5164#comment:2>
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