Re: [PATCH 0/5] Volatile Ranges (v12) & LSF-MM discussion fodder

[H. Peter Anvin]

On 04/02/2014 09:32 AM, H. Peter Anvin wrote:
> On 04/02/2014 09:30 AM, Johannes Weiner wrote:
>>
>> So between zero-fill and SIGBUS, I'd prefer the one which results in
>> the simpler user interface / fewer system calls.
>>
> 
> The use cases are different; I believe this should be a user space option.
> 

Case in point, for example: imagine a JIT.  You *really* don't want to
zero-fill memory behind the back of your JIT, as all zero memory may not
be a trapping instruction (it isn't on x86, for example, and if you are
unlucky you may be modifying *part* of an instruction.)

Thus, SIGBUS is the only safe option.

	-hpa


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