Messages in this thread | | | Date | Mon, 15 Jun 2009 12:44:15 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH] asm-generic: drop HARDIRQ_BITS definition from hardirq.h |
| |
[ Note: I prefer email to rostedt@goodmis.org over srostedt@redhat.com, just because I don't read my RH email as often. ]
On Sun, Jun 14, 2009 at 10:43:31PM +0200, Arnd Bergmann wrote: > linux/hardirq.h contains a fallback for HARDIRQ_BITS to 10 > if it's not defined, so it is pointless to define a default > of 8 in asm/hardirq.h. There does not seem to be a good > reason why an architecture would want to limit the number > of hardirqs this way.
After reading the thread again (from the beginning) I have a better idea of what you are talking about. But the above description is misleading.
The HARDIRQ_BITS has nothing to do with the number of IRQS, it has to do with the number of nested irqs allowed. Heck, 8 should be goog enough.
But the only thing I object to about this patch is that discription.
> > Reported-by: Mike Frysinger <vapier@gentoo.org> > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > include/asm-generic/hardirq.h | 13 ------------- > 1 files changed, 0 insertions(+), 13 deletions(-) > On Sunday 14 June 2009, Mike Frysinger wrote: > > Mike Frysinger wrote: > > is there any downsides to using a "too large" value ? i.e. if my > > system has less than 256, does it make any difference at all if it's > > set to 10 ? > > -mike > > None that I know of. I'm queuing this patch in my asm-generic tree now, > unless Steven or someone else has a better idea. > > Arnd <>< > > diff --git a/include/asm-generic/hardirq.h b/include/asm-generic/hardirq.h > index 3d5d2c9..23bb4da 100644 > --- a/include/asm-generic/hardirq.h > +++ b/include/asm-generic/hardirq.h > @@ -11,19 +11,6 @@ typedef struct { > > #include <linux/irq_cpustat.h> /* Standard mappings for irq_cpustat_t above */ > > -#ifndef HARDIRQ_BITS > -#define HARDIRQ_BITS 8 > -#endif > - > -/* > - * The hardirq mask has to be large enough to have > - * space for potentially all IRQ sources in the system > - * nesting on a single CPU: > - */ > -#if (1 << HARDIRQ_BITS) < NR_IRQS > -# error HARDIRQ_BITS is too low! > -#endif
For the content of the patch:
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Because it too is misleading.
The only reason I did not remove all arch defined HARDIQR_BITS and just default it to 10 or 8, is because one of the archs had that hardcoded in the asm, and I did not want to break it.
-- Steve
> - > #ifndef ack_bad_irq > static inline void ack_bad_irq(unsigned int irq) > { > -- > 1.6.3.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
| |