David Kewley wrote:
How is xfs doing these days with 4k stacks on x86 systems, or 8k stacks on
The former may be dicey in some situations (stacking - nfs, volume managers,
etc), I'd expect the latter to be OK.
I'm running RHEL 4, with xfs enabled in a kernel directly derived from the
RHEL 4 kernel. I'm on x86_64, and until today, I thought I was safe
stackwise because x86_64 keeps 8k stacks even when x86 is 4k. But Dave Jones
has confirmed that stack objects are twice as big on x86_64 as on x86,
Only some stack objects will be bigger - longs (and pointers) will be 64 bits
instead of 32. But I don't think you'll see a wholesale 2x increase on
average. x86_64 also passes args differently and that uses a little stack
Further, x86_64 does not move softirqs to the irq stack today, so that can add
to the troubles.
But overall it's my (un?)educated guess that x86_64 should be in better shape.
in as much danger for stack overflow as x86 is with 4k stacks.
Agreed so far?
How big is the danger, and what can I do to avoid it?
If you just run local xfs without stacking other drivers above/below it in the
IO chain, you'll be less likely to hit a problem.