Re: [Pyobjc-dev] In and out of NSData

[Bob I. <bo...@re...>]

On Tuesday, Jan 7, 2003, at 22:46 America/New_York, bb...@ma... wrote:

>> oh.. and I think these segfaults are doing something really nasty to 
>> my system (though I don't see exactly why it should), as my front 
>> terminal window (that I was using for Python) was going between 
>> normal display and completely white and unresponsive at a cycle time 
>> of about 5 seconds.. I did manage to close it eventually, and the 
>> other terminals seem fine.  I dunno if this is related, but I have 
>> never seen it happen before.
>
> Sounds like it is causing your system to swap heavily.   How much RAM 
> do you have?   Unless the subprocess was outputting lots and lots of 
> data-- which would have been visible-- the terminal window should have 
> been unaffected.

The subprocess was not running at this point, and no output was being 
processed (it had just segfaulted).  That's why it was strange.  I 
don't think this is a ram issue, I have 1GB on my powerbook.

>
> Odd but may indicate that something is broken on the bridge such that 
> it is trying to allocate a really huge chunk of memory within the 
> NSData (but that wouldn't make sense -- NSData/NSMutableData only 
> allocate address space, not physical RAM, until the first time you 
> touch a page of RAM... it wouldn't cause swap death unless you (a) 
> allocated a huge NSData and (b) tried to actually read/write from the 
> data object across a significant number of pages).

I haven't tried to allocate anything larger than a few kb at most and 
haven't really done any reading from them since I don't yet know of a 
way to get arbitrary data out of NSData and back into python in any 
reasonable manner.

-bob