Messages in this thread |  | | | Date | Tue, 9 Oct 2007 11:39:21 -0700 (PDT) | | From | Christoph Lameter <> | | Subject | Re: [13/18] x86_64: Allow fallback for the stack |
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On Mon, 8 Oct 2007, Nick Piggin wrote:
> The tight memory restrictions on stack usage do not come about because > of the difficulty in increasing the stack size :) It is because we want to > keep stack sizes small! > > Increasing the stack size 4K uses another 4MB of memory for every 1000 > threads you have, right? > > It would take a lot of good reason to move away from the general direction > we've been taking over the past years that 4/8K stacks are a good idea for > regular 32 and 64 bit builds in general.
We already use 32k stacks on IA64. So the memory argument fail there.
> > I have some concerns about the medium NUMA systems (a few dozen of nodes) > > also running out of stack since more data is placed on the stack through > > the policy layer and since we may end up with a couple of stacked > > filesystems. Most of the current NUMA systems on x86_64 are basically > > two nodes on one motherboard. The use of NUMA controls is likely > > limited there and the complexity of the filesystems is also not high. > > The solution has until now always been to fix the problems so they don't > use so much stack. Maybe a bigger stack is OK for you for 1024+ CPU > systems, but I don't think you'd be able to make that assumption for most > normal systems.
Yes that is why I made the stack size configurable.
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