diff options
author | Thomas Gleixner <tglx@linutronix.de> | 2009-07-21 05:09:39 -0400 |
---|---|---|
committer | Thomas Gleixner <tglx@linutronix.de> | 2009-07-21 08:35:07 -0400 |
commit | 591d2fb02ea80472d846c0b8507007806bdd69cc (patch) | |
tree | c7962a95a47bbdf664f15a504eff24c351f33613 /kernel | |
parent | aea1f7964ae6cba5eb419a958956deb9016b3341 (diff) |
genirq: Delegate irq affinity setting to the irq thread
irq_set_thread_affinity() calls set_cpus_allowed_ptr() which might
sleep, but irq_set_thread_affinity() is called with desc->lock held
and can be called from hard interrupt context as well. The code has
another bug as it does not hold a ref on the task struct as required
by set_cpus_allowed_ptr().
Just set the IRQTF_AFFINITY bit in action->thread_flags. The next time
the thread runs it migrates itself. Solves all of the above problems
nicely.
Add kerneldoc to irq_set_thread_affinity() while at it.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
LKML-Reference: <new-submission>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/irq/internals.h | 3 | ||||
-rw-r--r-- | kernel/irq/manage.c | 50 | ||||
-rw-r--r-- | kernel/irq/migration.c | 2 |
3 files changed, 46 insertions, 9 deletions
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h index 73468253143b..e70ed5592eb9 100644 --- a/kernel/irq/internals.h +++ b/kernel/irq/internals.h | |||
@@ -42,8 +42,7 @@ static inline void unregister_handler_proc(unsigned int irq, | |||
42 | 42 | ||
43 | extern int irq_select_affinity_usr(unsigned int irq); | 43 | extern int irq_select_affinity_usr(unsigned int irq); |
44 | 44 | ||
45 | extern void | 45 | extern void irq_set_thread_affinity(struct irq_desc *desc); |
46 | irq_set_thread_affinity(struct irq_desc *desc, const struct cpumask *cpumask); | ||
47 | 46 | ||
48 | /* | 47 | /* |
49 | * Debugging printout: | 48 | * Debugging printout: |
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 50da67672901..f0de36f13a44 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c | |||
@@ -80,14 +80,22 @@ int irq_can_set_affinity(unsigned int irq) | |||
80 | return 1; | 80 | return 1; |
81 | } | 81 | } |
82 | 82 | ||
83 | void | 83 | /** |
84 | irq_set_thread_affinity(struct irq_desc *desc, const struct cpumask *cpumask) | 84 | * irq_set_thread_affinity - Notify irq threads to adjust affinity |
85 | * @desc: irq descriptor which has affitnity changed | ||
86 | * | ||
87 | * We just set IRQTF_AFFINITY and delegate the affinity setting | ||
88 | * to the interrupt thread itself. We can not call | ||
89 | * set_cpus_allowed_ptr() here as we hold desc->lock and this | ||
90 | * code can be called from hard interrupt context. | ||
91 | */ | ||
92 | void irq_set_thread_affinity(struct irq_desc *desc) | ||
85 | { | 93 | { |
86 | struct irqaction *action = desc->action; | 94 | struct irqaction *action = desc->action; |
87 | 95 | ||
88 | while (action) { | 96 | while (action) { |
89 | if (action->thread) | 97 | if (action->thread) |
90 | set_cpus_allowed_ptr(action->thread, cpumask); | 98 | set_bit(IRQTF_AFFINITY, &action->thread_flags); |
91 | action = action->next; | 99 | action = action->next; |
92 | } | 100 | } |
93 | } | 101 | } |
@@ -112,7 +120,7 @@ int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask) | |||
112 | if (desc->status & IRQ_MOVE_PCNTXT) { | 120 | if (desc->status & IRQ_MOVE_PCNTXT) { |
113 | if (!desc->chip->set_affinity(irq, cpumask)) { | 121 | if (!desc->chip->set_affinity(irq, cpumask)) { |
114 | cpumask_copy(desc->affinity, cpumask); | 122 | cpumask_copy(desc->affinity, cpumask); |
115 | irq_set_thread_affinity(desc, cpumask); | 123 | irq_set_thread_affinity(desc); |
116 | } | 124 | } |
117 | } | 125 | } |
118 | else { | 126 | else { |
@@ -122,7 +130,7 @@ int irq_set_affinity(unsigned int irq, const struct cpumask *cpumask) | |||
122 | #else | 130 | #else |
123 | if (!desc->chip->set_affinity(irq, cpumask)) { | 131 | if (!desc->chip->set_affinity(irq, cpumask)) { |
124 | cpumask_copy(desc->affinity, cpumask); | 132 | cpumask_copy(desc->affinity, cpumask); |
125 | irq_set_thread_affinity(desc, cpumask); | 133 | irq_set_thread_affinity(desc); |
126 | } | 134 | } |
127 | #endif | 135 | #endif |
128 | desc->status |= IRQ_AFFINITY_SET; | 136 | desc->status |= IRQ_AFFINITY_SET; |
@@ -176,7 +184,7 @@ int irq_select_affinity_usr(unsigned int irq) | |||
176 | spin_lock_irqsave(&desc->lock, flags); | 184 | spin_lock_irqsave(&desc->lock, flags); |
177 | ret = setup_affinity(irq, desc); | 185 | ret = setup_affinity(irq, desc); |
178 | if (!ret) | 186 | if (!ret) |
179 | irq_set_thread_affinity(desc, desc->affinity); | 187 | irq_set_thread_affinity(desc); |
180 | spin_unlock_irqrestore(&desc->lock, flags); | 188 | spin_unlock_irqrestore(&desc->lock, flags); |
181 | 189 | ||
182 | return ret; | 190 | return ret; |
@@ -444,6 +452,34 @@ static int irq_wait_for_interrupt(struct irqaction *action) | |||
444 | } | 452 | } |
445 | 453 | ||
446 | /* | 454 | /* |
455 | * Check whether we need to change the affinity of the interrupt thread. | ||
456 | */ | ||
457 | static void | ||
458 | irq_thread_check_affinity(struct irq_desc *desc, struct irqaction *action) | ||
459 | { | ||
460 | cpumask_var_t mask; | ||
461 | |||
462 | if (!test_and_clear_bit(IRQTF_AFFINITY, &action->thread_flags)) | ||
463 | return; | ||
464 | |||
465 | /* | ||
466 | * In case we are out of memory we set IRQTF_AFFINITY again and | ||
467 | * try again next time | ||
468 | */ | ||
469 | if (!alloc_cpumask_var(&mask, GFP_KERNEL)) { | ||
470 | set_bit(IRQTF_AFFINITY, &action->thread_flags); | ||
471 | return; | ||
472 | } | ||
473 | |||
474 | spin_lock_irq(&desc->lock); | ||
475 | cpumask_copy(mask, desc->affinity); | ||
476 | spin_unlock_irq(&desc->lock); | ||
477 | |||
478 | set_cpus_allowed_ptr(current, mask); | ||
479 | free_cpumask_var(mask); | ||
480 | } | ||
481 | |||
482 | /* | ||
447 | * Interrupt handler thread | 483 | * Interrupt handler thread |
448 | */ | 484 | */ |
449 | static int irq_thread(void *data) | 485 | static int irq_thread(void *data) |
@@ -458,6 +494,8 @@ static int irq_thread(void *data) | |||
458 | 494 | ||
459 | while (!irq_wait_for_interrupt(action)) { | 495 | while (!irq_wait_for_interrupt(action)) { |
460 | 496 | ||
497 | irq_thread_check_affinity(desc, action); | ||
498 | |||
461 | atomic_inc(&desc->threads_active); | 499 | atomic_inc(&desc->threads_active); |
462 | 500 | ||
463 | spin_lock_irq(&desc->lock); | 501 | spin_lock_irq(&desc->lock); |
diff --git a/kernel/irq/migration.c b/kernel/irq/migration.c index cfe767ca1545..fcb6c96f2627 100644 --- a/kernel/irq/migration.c +++ b/kernel/irq/migration.c | |||
@@ -45,7 +45,7 @@ void move_masked_irq(int irq) | |||
45 | < nr_cpu_ids)) | 45 | < nr_cpu_ids)) |
46 | if (!desc->chip->set_affinity(irq, desc->pending_mask)) { | 46 | if (!desc->chip->set_affinity(irq, desc->pending_mask)) { |
47 | cpumask_copy(desc->affinity, desc->pending_mask); | 47 | cpumask_copy(desc->affinity, desc->pending_mask); |
48 | irq_set_thread_affinity(desc, desc->pending_mask); | 48 | irq_set_thread_affinity(desc); |
49 | } | 49 | } |
50 | 50 | ||
51 | cpumask_clear(desc->pending_mask); | 51 | cpumask_clear(desc->pending_mask); |