Messages in this thread Patch in this message | | | Date | Mon, 13 Apr 2009 15:20:58 -0700 | From | "Pallipadi, Venkatesh" <> | Subject | [PATCH] irq, x86: Remove IRQ_DISABLED check in process context IRQ move |
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As discussed in the thread here http://marc.info/?l=linux-kernel&m=123964468521142&w=2
On Fri, Apr 10, 2009 at 3:02 PM, Eric W. Biederman <ebiederm@xmission.com> wrote: > > It looks like some additional bugs have slipped in since last I looked. > > set_irq_affinity does this: > ifdef CONFIG_GENERIC_PENDING_IRQ > if (desc->status & IRQ_MOVE_PCNTXT || desc->status & IRQ_DISABLED) { > cpumask_copy(desc->affinity, cpumask); > desc->chip->set_affinity(irq, cpumask); > } else { > desc->status |= IRQ_MOVE_PENDING; > cpumask_copy(desc->pending_mask, cpumask); > } > #else > > That IRQ_DISABLED case is a software state and as such it has nothing to > do with how safe it is to move an irq in process context. >
"Pallipadi, Venkatesh" <venkatesh.pallipadi@intel.com> writes: > On Sat, 2009-04-11 at 04:01 -0700, Eric W. Biederman wrote: > > > > If the goal is moving MSIs, we should modify the msi code to be safe > > in process context and to set IRQ_MOVE_PCNTXT. > > > > The only reason we migrate MSIs in interrupt context today is that there > > wasn't infrastructure for support migration both in interrupt context > > and outside of it. > > Yes. The idea here was to force the MSI migration to happen in process > context. One of the patches in the series did > > disable_irq(dev->irq); > irq_set_affinity(dev->irq, cpumask_of(dev->cpu)); > enable_irq(dev->irq); > > with the above patch adding irq/manage code check for interrupt disabled > and moving the interrupt in process context. > > IIRC, there was no IRQ_MOVE_PCNTXT when we were developing this HPET > code and we ended up having this ugly hack. IRQ_MOVE_PCNTXT was there > when we eventually submitted the patch upstream. But, looks like I did a > blind rebasing instead of using IRQ_MOVE_PCNTXT in hpet MSI code. That > was my fault. Will send a patch to fix this ugliness.
Below patch fixes this. i.e., revert commit 932775a4ab622e3c99bd59f14cc7d96722f79501 and add PCNTXT to HPET MSI setup. Also removes copying of desc->affinity in generic code as set_affinity routines are doing it internally.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> --- arch/x86/kernel/apic/io_apic.c | 2 ++ kernel/irq/manage.c | 5 ++--- 2 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index 767fe7e..aaf8212 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -3667,12 +3667,14 @@ int arch_setup_hpet_msi(unsigned int irq) { int ret; struct msi_msg msg; + struct irq_desc *desc = irq_to_desc(irq); ret = msi_compose_msg(NULL, irq, &msg); if (ret < 0) return ret; hpet_msi_write(irq, &msg); + desc->status |= IRQ_MOVE_PCNTXT; set_irq_chip_and_handler_name(irq, &hpet_msi_type, handle_edge_irq, "edge"); diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 7e2e7dd..2734eca 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -109,10 +109,9 @@ int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask) spin_lock_irqsave(&desc->lock, flags); #ifdef CONFIG_GENERIC_PENDING_IRQ - if (desc->status & IRQ_MOVE_PCNTXT || desc->status & IRQ_DISABLED) { - cpumask_copy(desc->affinity, cpumask); + if (desc->status & IRQ_MOVE_PCNTXT) desc->chip->set_affinity(irq, cpumask); - } else { + else { desc->status |= IRQ_MOVE_PENDING; cpumask_copy(desc->pending_mask, cpumask); } -- 1.6.0.6
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