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From: Andi Kleen <ak@suse.de>
To: Akinobu Mita <mita@miraclelinux.com>
Subject: Re: [patch 3/6] fault-injection capability for alloc_pages()
Date: Thu, 31 Aug 2006 12:25:02 +0200
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On Thursday 31 August 2006 12:07, Akinobu Mita wrote:
> This patch provides fault-injection capability for alloc_pages()
> 
> boot option:
> 
> 	fail_page_alloc=<probability>,<interval>,<times>,<space>
> 
> 	<probability>
> 
> 		specifies how often it should fail in percent.
> 
> 	<interval>
> 
> 		specifies the interval of failures.
> 
> 	<times>
> 
> 		specifies how many times failures may happen at most.
> 
> 	<space>
> 
> 		specifies the size of free space where memory can be allocated
> 		safely in pages.
> 
> Example:
> 
> 	fail_page_alloc=100,10,-1,0
> 
> page allocation fails once per 10 times.

I still think this will need some better filters to be useful. At least
a optional uid filter perhaps (make sure to handle the interrupt case
correctly, interrupts don't belong to the uid) , and perhaps an option to only 
fail GFP_ATOMIC.

With arbitary failing the system will just be unusable, right? Or would
you run some system you use this way? @)

Another possibility would be to look up __builtin_return_address(0) in 
the module table and allow failing only for a specific module.


-andi
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