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Date: Sun, 31 Aug 2003 03:52:03 +0100 (BST)
From: "=?iso-8859-1?q?Pedro=20F.=20Giffuni?=" <giffunip@yahoo.com>
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Subject: Re: Non-executable mappings now in NetBSD too
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Ugh... or just consider not all equipment out there needs JIT Java, and make it
a kernel option!

cheers,

   Pedro.

 --- Andrew Lankford <arlankfo@141.com> wrote: > > Whilst the Java bytecode is
not natively executable, a JIT JVM >needs to be
> able towrite and immediately execute native code.  >The OpenBSD W^X approach
> would require system calls between the >compilation and execution steps.  My
> understanding of current JIT >is that the compilation is done is very small
> pieces and adding >the overhead of a pair of system calls would basically
> kill it.
> 
> Even simpler to compile to a temporary file and then exit the temporary file.
>  Woohoo, potential race condition! <br><br>
> ...Or you could make a nifty new system call that creates a pipe to a newly
> forked child process.  You write the compiled executable to the fork, and the
> child jumps to the begining of that compiled code as soon as your parent
> process closes the pipe!<br><br>
> Gratuitous/pointless, but fun to think about.
> 
> 
> Andrew Lankford 
> 
> 
>  
>                     

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