[S390] qdio: optimize cache line usage of struct qdio_irq

Remove a memset hack that relied on the internal layout of the
qdio_irq struct and move the per device statistics data into an own
cache line to avoid cache line bashing between the inbound and the
outbound queue tasklets. Also reduce the number of allocated queues
from 32 to 4 which is the current maximum. That saves a cache line
in struct qdio_irq.

Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 9 insertions, 1 deletions

diff --git a/drivers/s390/cio/qdio_setup.c b/drivers/s390/cio/qdio_setup.c
index 4464907715a4..7f4a75465140 100644
--- a/drivers/s390/cio/qdio_setup.c
+++ b/drivers/s390/cio/qdio_setup.c
@@ -382,7 +382,15 @@ int qdio_setup_irq(struct qdio_initialize *init_data)
         struct qdio_irq *irq_ptr = init_data->cdev->private->qdio_data;
         int rc;
 
-        memset(irq_ptr, 0, ((char *)&irq_ptr->qdr) - ((char *)irq_ptr));
+        memset(&irq_ptr->qib, 0, sizeof(irq_ptr->qib));
+        memset(&irq_ptr->siga_flag, 0, sizeof(irq_ptr->siga_flag));
+        memset(&irq_ptr->ccw, 0, sizeof(irq_ptr->ccw));
+        memset(&irq_ptr->ssqd_desc, 0, sizeof(irq_ptr->ssqd_desc));
+        memset(&irq_ptr->perf_stat, 0, sizeof(irq_ptr->perf_stat));
+
+        irq_ptr->debugfs_dev = irq_ptr->debugfs_perf = NULL;
+        irq_ptr->sch_token = irq_ptr->state = irq_ptr->perf_stat_enabled = 0;
+
         /* wipes qib.ac, required by ar7063 */
         memset(irq_ptr->qdr, 0, sizeof(struct qdr));