6e2ac66470
While running my MCA test (hardware error injection) on 2.6.19, I got some warning like following: > BUG: warning at kernel/irq/migration.c:27/move_masked_irq() > > Call Trace: > [<a000000100013d20>] show_stack+0x40/0xa0 > sp=e00000006b2578d0 bsp=e00000006b2510b0 > [<a000000100013db0>] dump_stack+0x30/0x60 > sp=e00000006b257aa0 bsp=e00000006b251098 > [<a0000001000de430>] move_masked_irq+0xb0/0x240 > sp=e00000006b257aa0 bsp=e00000006b251070 > [<a0000001000de6a0>] move_native_irq+0xe0/0x180 > sp=e00000006b257aa0 bsp=e00000006b251040 > [<a00000010004ff50>] iosapic_end_level_irq+0x30/0xe0 > sp=e00000006b257aa0 bsp=e00000006b251020 > [<a0000001000d94d0>] __do_IRQ+0x170/0x400 > sp=e00000006b257aa0 bsp=e00000006b250fd8 > [<a0000001000116f0>] ia64_handle_irq+0x1b0/0x260 > sp=e00000006b257aa0 bsp=e00000006b250fa8 > [<a00000010000c3a0>] ia64_leave_kernel+0x0/0x280 > sp=e00000006b257aa0 bsp=e00000006b250fa8 > [<a000000100690cf0>] _spin_unlock_irqrestore+0x30/0x60 > sp=e00000006b257c70 bsp=e00000006b250f90 It comes from: [kernel/irq/migration.c] 26 if (CHECK_IRQ_PER_CPU(desc->status)) { 27 WARN_ON(1); 28 return; 29 } By putting some printk in kernel, I found that irqbalance is trying to move CPEI which is handled as PER_CPU irq. That's why. CPEI(Corrected Platform Error Interrupt) is ia64 specific irq, is allowed to pin to particular processor which selected by the platform, and even it is PER_CPU but it has set_affinity handler (=iosapic_set_affinity) as same as other IO-SAPIC-level interrupts. (I don't know why, but I guess that there would be typical situation where the handler for migration is needed, such as hotplug - the processor going to be offline/hot-removed.) To shut up this warning, there are 2 way at least: a) fix CPEI stuff b) prohibit setting affinity to PER_CPU irq I'm not sure what stuff of CPEI need to be fixed, but I think that returning error to attempting move PER_CPU irq is useful for all applications since it will never work. Following small patch takes b) style. It works, the warning disappeared and irqbalance still runs well. Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Cc: Arjan van de Ven <arjan@infradead.org> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
172 lines
3.7 KiB
C
172 lines
3.7 KiB
C
/*
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* linux/kernel/irq/proc.c
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*
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* Copyright (C) 1992, 1998-2004 Linus Torvalds, Ingo Molnar
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*
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* This file contains the /proc/irq/ handling code.
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*/
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#include <linux/irq.h>
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#include <linux/proc_fs.h>
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#include <linux/interrupt.h>
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#include "internals.h"
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static struct proc_dir_entry *root_irq_dir;
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#ifdef CONFIG_SMP
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#ifdef CONFIG_GENERIC_PENDING_IRQ
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void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
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{
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set_balance_irq_affinity(irq, mask_val);
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/*
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* Save these away for later use. Re-progam when the
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* interrupt is pending
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*/
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set_pending_irq(irq, mask_val);
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}
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#else
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void proc_set_irq_affinity(unsigned int irq, cpumask_t mask_val)
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{
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set_balance_irq_affinity(irq, mask_val);
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irq_desc[irq].affinity = mask_val;
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irq_desc[irq].chip->set_affinity(irq, mask_val);
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}
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#endif
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static int irq_affinity_read_proc(char *page, char **start, off_t off,
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int count, int *eof, void *data)
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{
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int len = cpumask_scnprintf(page, count, irq_desc[(long)data].affinity);
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if (count - len < 2)
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return -EINVAL;
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len += sprintf(page + len, "\n");
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return len;
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}
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int no_irq_affinity;
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static int irq_affinity_write_proc(struct file *file, const char __user *buffer,
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unsigned long count, void *data)
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{
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unsigned int irq = (int)(long)data, full_count = count, err;
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cpumask_t new_value, tmp;
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if (!irq_desc[irq].chip->set_affinity || no_irq_affinity ||
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CHECK_IRQ_PER_CPU(irq_desc[irq].status))
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return -EIO;
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err = cpumask_parse_user(buffer, count, new_value);
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if (err)
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return err;
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/*
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* Do not allow disabling IRQs completely - it's a too easy
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* way to make the system unusable accidentally :-) At least
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* one online CPU still has to be targeted.
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*/
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cpus_and(tmp, new_value, cpu_online_map);
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if (cpus_empty(tmp))
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/* Special case for empty set - allow the architecture
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code to set default SMP affinity. */
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return select_smp_affinity(irq) ? -EINVAL : full_count;
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proc_set_irq_affinity(irq, new_value);
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return full_count;
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}
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#endif
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#define MAX_NAMELEN 128
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static int name_unique(unsigned int irq, struct irqaction *new_action)
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{
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struct irq_desc *desc = irq_desc + irq;
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struct irqaction *action;
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for (action = desc->action ; action; action = action->next)
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if ((action != new_action) && action->name &&
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!strcmp(new_action->name, action->name))
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return 0;
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return 1;
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}
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void register_handler_proc(unsigned int irq, struct irqaction *action)
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{
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char name [MAX_NAMELEN];
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if (!irq_desc[irq].dir || action->dir || !action->name ||
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!name_unique(irq, action))
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return;
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memset(name, 0, MAX_NAMELEN);
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snprintf(name, MAX_NAMELEN, "%s", action->name);
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/* create /proc/irq/1234/handler/ */
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action->dir = proc_mkdir(name, irq_desc[irq].dir);
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}
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#undef MAX_NAMELEN
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#define MAX_NAMELEN 10
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void register_irq_proc(unsigned int irq)
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{
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char name [MAX_NAMELEN];
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if (!root_irq_dir ||
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(irq_desc[irq].chip == &no_irq_chip) ||
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irq_desc[irq].dir)
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return;
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memset(name, 0, MAX_NAMELEN);
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sprintf(name, "%d", irq);
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/* create /proc/irq/1234 */
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irq_desc[irq].dir = proc_mkdir(name, root_irq_dir);
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#ifdef CONFIG_SMP
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{
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struct proc_dir_entry *entry;
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/* create /proc/irq/<irq>/smp_affinity */
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entry = create_proc_entry("smp_affinity", 0600, irq_desc[irq].dir);
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if (entry) {
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entry->nlink = 1;
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entry->data = (void *)(long)irq;
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entry->read_proc = irq_affinity_read_proc;
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entry->write_proc = irq_affinity_write_proc;
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}
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}
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#endif
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}
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#undef MAX_NAMELEN
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void unregister_handler_proc(unsigned int irq, struct irqaction *action)
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{
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if (action->dir)
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remove_proc_entry(action->dir->name, irq_desc[irq].dir);
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}
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void init_irq_proc(void)
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{
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int i;
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/* create /proc/irq */
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root_irq_dir = proc_mkdir("irq", NULL);
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if (!root_irq_dir)
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return;
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/*
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* Create entries for all existing IRQs.
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*/
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for (i = 0; i < NR_IRQS; i++)
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register_irq_proc(i);
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}
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