Brian, Yes indeed, s/limited/unlimited/. I was thinking perhaps by "unlimited" they meant allocating the stack from virtual memory, but anyway a source of possible trouble. Thanks Peter
On 8/19/08, Brian Dobbins <[EMAIL PROTECTED]> wrote: > > > On Tue, Aug 19, 2008 at 8:04 PM, Peter St. John <[EMAIL PROTECTED]>wrote: > >> What I meant was: surely the stacksize is not really limited, even it it >> is configured without limits? > > > If you meant to say *un*limited there, then yes, it's not really > unlimited. Someone with more kernel knowledge will certainly correct me if > I'm wrong here, but I believe the stack is allocated 'upward' from the end > of where your data/program reside in memory, whereas variables on the heap > are (or tend to be, in fragmented memories) allocated 'downward' from the > maximum available free memory. So, at some point, those two will meet if > you have limited ram, and your stack size most certainly won't be > 'unlimited' at that point. > > ... Bear in mind, my only experience with this is from the old 2.4 series > kernels, where you had to modify how heap allocations were done in order to > get above 2GB on 32-bit machines. Given that that's ancient history, things > may have changed. ;) > > (And, in more detail - if you set a limit, you get just that much... if > you set 'unlimited', you get up until stack + heap allocations (+ data > segments, OS stuff, etc.) run you out of memory. Also, while heap > allocations can be swapped out to virtual memory, I'm not too sure stack can > be, as it tends to be faster, and used a bit differently. Anyone know?) > > Cheers, > - Brian > > > Brian Dobbins > Yale Engineering HPC > >
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