From 6ec3cfeca04622e3d80c9270191cd7f5f88214af Mon Sep 17 00:00:00 2001 From: "Pallipadi, Venkatesh" Date: Mon, 13 Apr 2009 15:20:58 -0700 Subject: x86, irq: Remove IRQ_DISABLED check in process context IRQ move As discussed in the thread here: http://marc.info/?l=linux-kernel&m=123964468521142&w=2 Eric W. Biederman observed: > 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. [...] > > 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. Below patch fixes this. i.e., revert commit 932775a4ab622e3c99bd59f14cc and add PCNTXT to HPET MSI setup. Also removes copying of desc->affinity in generic code as set_affinity routines are doing it internally. Reported-by: "Eric W. Biederman" Signed-off-by: Venkatesh Pallipadi Acked-by: "Eric W. Biederman" Cc: "Li Shaohua" Cc: Gary Hade Cc: "lcm@us.ibm.com" Cc: suresh.b.siddha@intel.com LKML-Reference: <20090413222058.GB8211@linux-os.sc.intel.com> Signed-off-by: Ingo Molnar diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index a2789e4..30da617 100644 --- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -3670,12 +3670,14 @@ 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); } -- cgit v0.10.2 From ca713c2ab0eea3458962983e4a7e13430ea479b8 Mon Sep 17 00:00:00 2001 From: Yinghai Lu Date: Wed, 15 Apr 2009 18:39:13 -0700 Subject: x86/irq: mark NUMA_MIGRATE_IRQ_DESC broken It causes crash on system with lots of cards with MSI-X when irq_balancer enabled... The patches fixing it were both complex and fragile, according to Eric they were also doing quite dangerous things to the hardware. Instead we now have patches that solve this problem via static NUMA node mappings - not dynamic allocation and balancing. The patches are much simpler than this method but are still too large outside of the merge window, so we mark the dynamic balancer as broken for now, and queue up the new approach for v2.6.31. [ Impact: deactivate broken kernel feature ] Reported-by: Suresh Siddha Signed-off-by: Yinghai Lu Cc: Andrew Morton Cc: "Eric W. Biederman" Cc: Rusty Russell LKML-Reference: <49E68C41.4020801@kernel.org> Signed-off-by: Ingo Molnar diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index bc25b9f..b1d2be7 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -277,6 +277,7 @@ config SPARSE_IRQ config NUMA_MIGRATE_IRQ_DESC bool "Move irq desc when changing irq smp_affinity" depends on SPARSE_IRQ && NUMA + depends on BROKEN default n ---help--- This enables moving irq_desc to cpu/node that irq will use handled. -- cgit v0.10.2