Messages in this thread | | | Date | Wed, 11 Feb 2009 13:42:32 -0500 (EST) | From | Steven Rostedt <> | Subject | RE: [PATCH 0/8] git pull request for tip/tracing/core |
| |
On Wed, 11 Feb 2009, Luck, Tony wrote:
> > The bits in question is really the number of possible nested interrupts > > that can happen. We take the paranoid approach that we can have a max > > nesting of NR_IRQS. Perhaps this can be changed, and just do a max of > > 1<<10 nesting? And have a big warn on if it happens to be bigger, or fall > > to another counter if it is bigger. > > > > 1000 nested IRQs seems a bit extreme :-/ > > Ah, I see. Then the answer is very different. The number of nested > interrupts possible on a cpu is limited by the number of priority > classes for interrupts (See Table 5-8 on page 2:112 of the Itanium > software developers manual). Effectively the max nesting depth is > 16. > > 1000 nested interrupts would be certain to run us out of stack.
Ingo,
Do you think this is a good assumption to make, that no arch will have over 1<<10 nested interrupts. We can add a WARN_ON if it happens. Then we can make all archs have a 10 bit offset. Smaller may also be sufficient.
-- Steve
| |