On Wed, Sep 25, 2013 at 06:55:47AM +1000, Benjamin Herrenschmidt wrote: > On Tue, 2013-09-24 at 15:56 +0200, Frederic Weisbecker wrote: > > On Tue, Sep 24, 2013 at 02:42:57PM +1000, Benjamin Herrenschmidt wrote: > > > On Tue, 2013-09-24 at 04:44 +0200, Frederic Weisbecker wrote: > > > > So the safest way to fix this is to unconditionally call do_softirq() > > > > from irq_exit(). > > > > A performance penalty may come along but safety primes. > > > > > > > > We should probably do that and work on longer term solutions (Kconfig > > > > based arch switch, etc...) > > > > for the next merge window? > > > > > > As you prefer, though I'm keen on getting the "fast" version in RHEL7 if > > > RH will take it :-) > > > > So what is the fast version? Converting __do_softirq() to do_softirq() > > unconditionally. > > > > RH will accept any fix that goes upstream. > > No, me fixing powerpc do_IRQ to do irq_exit run on the irq stack, and > your fix for everybody else with an ifdef such that x86_64 and powerpc > get to skip the additional stack switch. > > > > > > > From the generic code POV, it's a one-liner #ifdef to select between > > > do_softirq and __do_softirq() right ? Then it's up to the arch to > > > #define I_CAN_DO_FAST ! > > > > I'd rather say #define I_CAN_DO_SAFE :) > > > > But I guess the kind of symbol we want is some > > ARCH_HAS_IRQ_STACK_LOW_HANDLER > > ARCH_IRQ_EXIT_ON_IRQ_STACK
Ok, I'll pick this one. Thanks! > > Cheers, > Ben. > > > > > > > > I'll respin the series plus the regression fix, unless somebody has a > > > > better solution. > > > > > > Cheers, > > > Ben. > > > > > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
