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authorJan Glauber <jang@linux.vnet.ibm.com>2010-05-17 12:00:15 +0400
committerMartin Schwidefsky <sky@mschwide.boeblingen.de.ibm.com>2010-05-17 12:00:17 +0400
commitf3eb20fafdc10aea0fb13b113ac3b9a3dc9a5dc6 (patch)
tree1025617dba903e0276efbfcd8e439ed0d475580c /drivers/s390/cio
parent09a308f384c4ad2fb45959f5da9918e812207c50 (diff)
downloadlinux-f3eb20fafdc10aea0fb13b113ac3b9a3dc9a5dc6.tar.xz
[S390] qdio: prevent starvation on PCI devices
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>
Diffstat (limited to 'drivers/s390/cio')
-rw-r--r--drivers/s390/cio/qdio_main.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index 1fc81268330e..f4fd6cd4dc08 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -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);
}
}