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

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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>
This commit is contained in:
Jan Glauber
2010-02-26 22:37:37 +01:00
committed by Martin Schwidefsky
parent d307297f73
commit 432ac5e04b
3 changed files with 14 additions and 8 deletions
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10
drivers/s390/cio/qdio_setup.c
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@@ -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));