Re: [PATCH -rt 2/9] Dont allow non-threaded softirqs and threaded hardirqs
-- On Mon, 30 Jul 2007, Ingo Molnar wrote: > > From: Steven Rostedt <[EMAIL PROTECTED]> > > > > I think this was sent before, and it did cause problems before. Would > > there be *any* reason to have non-threaded softirqs but threaded > > hardirqs. I can see lots of issues with that. > > please elaborate in precise terms: what issues can you see? > Hi Ingo, I don't remember the exact details, I can try to find the thread. But I remember someone was having their system lock up strangly. We later found that they had softirqs as normal softirqs and interrupts as threads. I think there was some driver that didn't expect the softirq to preempt the irq handler. Perhaps the softirq was using spin_lock_irq while the irq thread was just using spin_lock, which I can see as being something normal. The standard Linux does not expect an interrupt to be preempted by a softirq, and with interrupts as threads but not softirqs, I can see that happening a lot. -- Steve - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH -rt 2/9] Dont allow non-threaded softirqs and threaded hardirqs
* Daniel Walker <[EMAIL PROTECTED]> wrote: > From: Steven Rostedt <[EMAIL PROTECTED]> > > I think this was sent before, and it did cause problems before. Would > there be *any* reason to have non-threaded softirqs but threaded > hardirqs. I can see lots of issues with that. please elaborate in precise terms: what issues can you see? Ingo - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH -rt 2/9] Dont allow non-threaded softirqs and threaded hardirqs
* Daniel Walker [EMAIL PROTECTED] wrote: From: Steven Rostedt [EMAIL PROTECTED] I think this was sent before, and it did cause problems before. Would there be *any* reason to have non-threaded softirqs but threaded hardirqs. I can see lots of issues with that. please elaborate in precise terms: what issues can you see? Ingo - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH -rt 2/9] Dont allow non-threaded softirqs and threaded hardirqs
-- On Mon, 30 Jul 2007, Ingo Molnar wrote: From: Steven Rostedt [EMAIL PROTECTED] I think this was sent before, and it did cause problems before. Would there be *any* reason to have non-threaded softirqs but threaded hardirqs. I can see lots of issues with that. please elaborate in precise terms: what issues can you see? Hi Ingo, I don't remember the exact details, I can try to find the thread. But I remember someone was having their system lock up strangly. We later found that they had softirqs as normal softirqs and interrupts as threads. I think there was some driver that didn't expect the softirq to preempt the irq handler. Perhaps the softirq was using spin_lock_irq while the irq thread was just using spin_lock, which I can see as being something normal. The standard Linux does not expect an interrupt to be preempted by a softirq, and with interrupts as threads but not softirqs, I can see that happening a lot. -- Steve - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH -rt 2/9] Dont allow non-threaded softirqs and threaded hardirqs
From: Steven Rostedt <[EMAIL PROTECTED]> Ingo, I think this was sent before, and it did cause problems before. Would there be *any* reason to have non-threaded softirqs but threaded hardirqs. I can see lots of issues with that. This patch has selecting hardirqs also select softirqs as threads. Signed-off-by: Steven Rostedt <[EMAIL PROTECTED]> --- kernel/Kconfig.preempt |1 + 1 file changed, 1 insertion(+) Index: linux-2.6.22/kernel/Kconfig.preempt === --- linux-2.6.22.orig/kernel/Kconfig.preempt2007-07-26 14:59:11.0 + +++ linux-2.6.22/kernel/Kconfig.preempt 2007-07-26 14:59:48.0 + @@ -106,6 +106,7 @@ config PREEMPT_HARDIRQS bool "Thread Hardirqs" default n depends on !GENERIC_HARDIRQS_NO__DO_IRQ + select PREEMPT_SOFTIRQS help This option reduces the latency of the kernel by 'threading' hardirqs. This means that all (or selected) hardirqs will run -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH -rt 2/9] Dont allow non-threaded softirqs and threaded hardirqs
From: Steven Rostedt [EMAIL PROTECTED] Ingo, I think this was sent before, and it did cause problems before. Would there be *any* reason to have non-threaded softirqs but threaded hardirqs. I can see lots of issues with that. This patch has selecting hardirqs also select softirqs as threads. Signed-off-by: Steven Rostedt [EMAIL PROTECTED] --- kernel/Kconfig.preempt |1 + 1 file changed, 1 insertion(+) Index: linux-2.6.22/kernel/Kconfig.preempt === --- linux-2.6.22.orig/kernel/Kconfig.preempt2007-07-26 14:59:11.0 + +++ linux-2.6.22/kernel/Kconfig.preempt 2007-07-26 14:59:48.0 + @@ -106,6 +106,7 @@ config PREEMPT_HARDIRQS bool Thread Hardirqs default n depends on !GENERIC_HARDIRQS_NO__DO_IRQ + select PREEMPT_SOFTIRQS help This option reduces the latency of the kernel by 'threading' hardirqs. This means that all (or selected) hardirqs will run -- - To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
