Messages in this thread | | | Date | Sat, 12 Jan 2002 17:17:49 +0100 | From | Andrea Arcangeli <> | Subject | Re: Q: behaviour of mlockall(MCL_FUTURE) and VM_GROWSDOWN segments |
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On Sat, Jan 12, 2002 at 05:07:42PM +0100, Manfred Spraul wrote: > Andi Kleen wrote: > > > > For the stack they can get minor faults anyways when they allocate new > > stack space below ESP. There is no good way to fix that from the kernel; the > > application has to preallocate its memory on stack. I think it's reasonable > > if it does the same for holes on the stack. > > > Ok, everyone agrees that mlockall() should not grow VM_GROWSDOWN > segments to their maximum size.
Ah, definitely. I must have misunderstood something in the discussion sorry, I thought we were just discussiong the below issue, and I completly missed the "maximum size" one.
All I was trying to find out here, was about the intermediate pages between vm_start and vm_end of a VM_GROWSDOWN|VM_LOCKED vma, exactly your example below.
> Should the page fault handler fill the hole created by > > void * grow_stack(void) > { > char data[100000]; > data[0] = '0'; > return data; > } > > The principle of least surprise would mean filling holes, but OTHO sane > apps would use memset(data,0,sizeof(data)).
yep.
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