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[S390] qdio: prevent starvation on PCI devices

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If adapter interrupts are not available and traditional IO interrupts
are used for qdio the inbound tasklet continued to run if new data
arrived. That could possibly block other tasklets scheduled on the
same CPU. If new data arrives schedule the tasklet again instead of
directly processing the new data.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Jan Glauber 2010-05-17 10:00:15 +02:00 committed by Martin Schwidefsky
parent 09a308f384
commit f3eb20fafd
1 changed files with 7 additions and 3 deletions
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10
drivers/s390/cio/qdio_main.c
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@ -606,7 +606,7 @@ static void qdio_kick_handler(struct qdio_q *q)
static void __qdio_inbound_processing(struct qdio_q *q)
{
qperf_inc(q, tasklet_inbound);
again:
if (!qdio_inbound_q_moved(q))
return;
@ -615,7 +615,10 @@ again:
if (!qdio_inbound_q_done(q)) {
/* means poll time is not yet over */
qperf_inc(q, tasklet_inbound_resched);
goto again;
if (likely(q->irq_ptr->state != QDIO_IRQ_STATE_STOPPED)) {
tasklet_schedule(&q->tasklet);
return;
}
}
qdio_stop_polling(q);
@ -625,7 +628,8 @@ again:
*/
if (!qdio_inbound_q_done(q)) {
qperf_inc(q, tasklet_inbound_resched2);
goto again;
if (likely(q->irq_ptr->state != QDIO_IRQ_STATE_STOPPED))
tasklet_schedule(&q->tasklet);
}
}