Re: kdump regression compared to v2.6.35

Tejun Heo
2010-08-30T16:38:44Z

Can you please try the following patch?

Thanks.

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index a2dccfc..f57cd6e 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -1224,6 +1224,8 @@ __acquires(&gcwq->lock)
{
struct global_cwq *gcwq = worker->gcwq;
struct task_struct *task = worker->task;
+ static unsigned int cnt;
+ int rc;

while (true) {
/*
@@ -1232,8 +1234,11 @@ __acquires(&gcwq->lock)
* it races with cpu hotunplug operation. Verify
* against GCWQ_DISASSOCIATED.
*/
- if (!(gcwq->flags & GCWQ_DISASSOCIATED))
- set_cpus_allowed_ptr(task, get_cpu_mask(gcwq->cpu));
+ if (!(gcwq->flags & GCWQ_DISASSOCIATED)) {
+ rc = set_cpus_allowed_ptr(task, get_cpu_mask(gcwq->cpu));
+ if (rc && ++cnt < 10)
+ printk("XXX set_cpus_allowed_ptr() failed w/ %d\n", rc);
+ }

spin_lock_irq(&gcwq->lock);
if (gcwq->flags & GCWQ_DISASSOCIATED)
@@ -1985,13 +1990,16 @@ repeat:
struct cpu_workqueue_struct *cwq = get_cwq(tcpu, wq);
struct global_cwq *gcwq = cwq->gcwq;
struct work_struct *work, *n;
+ bool bound;

__set_current_state(TASK_RUNNING);
mayday_clear_cpu(cpu, wq->mayday_mask);

/* migrate to the target cpu if possible */
rescuer->gcwq = gcwq;
- worker_maybe_bind_and_lock(rescuer);
+ printk("XXX %s: rescuer dispatching to cpu%u\n", wq->name, gcwq->cpu);
+ bound = worker_maybe_bind_and_lock(rescuer);
+ printk("XXX %s: rescuer done binding, bound=%d\n", wq->name, bound);

/*
* Slurp in all works issued via this workqueue and
@@ -3558,8 +3566,7 @@ static int __init init_workqueues(void)
spin_lock_init(&gcwq->lock);
INIT_LIST_HEAD(&gcwq->worklist);
gcwq->cpu = cpu;
- if (cpu == WORK_CPU_UNBOUND)
- gcwq->flags |= GCWQ_DISASSOCIATED;
+ gcwq->flags |= GCWQ_DISASSOCIATED;

INIT_LIST_HEAD(&gcwq->idle_list);
for (i = 0; i < BUSY_WORKER_HASH_SIZE; i++)
@@ -3583,6 +3590,7 @@ static int __init init_workqueues(void)
struct global_cwq *gcwq = get_gcwq(cpu);
struct worker *worker;

+ gcwq->flags &= ~GCWQ_DISASSOCIATED;
worker = create_worker(gcwq, true);
BUG_ON(!worker);
spin_lock_irq(&gcwq->lock);