[S390] cio: reduce cpu utilization during device scan
Minimize calls to cpu intensive function get_subchannel_by_schid()
by introducing function for_each_subchannel_staged() which
temporarily caches the information about registered subchannels
in a bitmap.
Signed-off-by: Peter Oberparleiter <peter.oberparleiter@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c
index 12a344c..93e6f74 100644
--- a/drivers/s390/cio/chsc.c
+++ b/drivers/s390/cio/chsc.c
@@ -136,17 +136,13 @@
sch->driver->termination(sch);
}
-static int
-s390_subchannel_remove_chpid(struct device *dev, void *data)
+static int s390_subchannel_remove_chpid(struct subchannel *sch, void *data)
{
int j;
int mask;
- struct subchannel *sch;
- struct chp_id *chpid;
+ struct chp_id *chpid = data;
struct schib schib;
- sch = to_subchannel(dev);
- chpid = data;
for (j = 0; j < 8; j++) {
mask = 0x80 >> j;
if ((sch->schib.pmcw.pim & mask) &&
@@ -202,12 +198,10 @@
if (chp_get_status(chpid) <= 0)
return;
- bus_for_each_dev(&css_bus_type, NULL, &chpid,
- s390_subchannel_remove_chpid);
+ for_each_subchannel_staged(s390_subchannel_remove_chpid, NULL, &chpid);
}
-static int
-s390_process_res_acc_new_sch(struct subchannel_id schid)
+static int s390_process_res_acc_new_sch(struct subchannel_id schid, void *data)
{
struct schib schib;
/*
@@ -253,18 +247,10 @@
return 0;
}
-static int
-__s390_process_res_acc(struct subchannel_id schid, void *data)
+static int __s390_process_res_acc(struct subchannel *sch, void *data)
{
int chp_mask, old_lpm;
- struct res_acc_data *res_data;
- struct subchannel *sch;
-
- res_data = data;
- sch = get_subchannel_by_schid(schid);
- if (!sch)
- /* Check if a subchannel is newly available. */
- return s390_process_res_acc_new_sch(schid);
+ struct res_acc_data *res_data = data;
spin_lock_irq(sch->lock);
chp_mask = get_res_chpid_mask(&sch->ssd_info, res_data);
@@ -283,7 +269,7 @@
sch->driver->verify(sch);
out:
spin_unlock_irq(sch->lock);
- put_device(&sch->dev);
+
return 0;
}
@@ -306,7 +292,8 @@
* The more information we have (info), the less scanning
* will we have to do.
*/
- for_each_subchannel(__s390_process_res_acc, res_data);
+ for_each_subchannel_staged(__s390_process_res_acc,
+ s390_process_res_acc_new_sch, res_data);
}
static int
@@ -500,8 +487,7 @@
} while (sei_area->flags & 0x80);
}
-static int
-__chp_add_new_sch(struct subchannel_id schid)
+static int __chp_add_new_sch(struct subchannel_id schid, void *data)
{
struct schib schib;
@@ -515,35 +501,27 @@
}
-static int
-__chp_add(struct subchannel_id schid, void *data)
+static int __chp_add(struct subchannel *sch, void *data)
{
int i, mask;
- struct chp_id *chpid;
- struct subchannel *sch;
+ struct chp_id *chpid = data;
- chpid = data;
- sch = get_subchannel_by_schid(schid);
- if (!sch)
- /* Check if the subchannel is now available. */
- return __chp_add_new_sch(schid);
spin_lock_irq(sch->lock);
for (i=0; i<8; i++) {
mask = 0x80 >> i;
if ((sch->schib.pmcw.pim & mask) &&
- (sch->schib.pmcw.chpid[i] == chpid->id)) {
- if (stsch(sch->schid, &sch->schib) != 0) {
- /* Endgame. */
- spin_unlock_irq(sch->lock);
- return -ENXIO;
- }
+ (sch->schib.pmcw.chpid[i] == chpid->id))
break;
- }
}
if (i==8) {
spin_unlock_irq(sch->lock);
return 0;
}
+ if (stsch(sch->schid, &sch->schib)) {
+ spin_unlock_irq(sch->lock);
+ css_schedule_eval(sch->schid);
+ return 0;
+ }
sch->lpm = ((sch->schib.pmcw.pim &
sch->schib.pmcw.pam &
sch->schib.pmcw.pom)
@@ -553,7 +531,7 @@
sch->driver->verify(sch);
spin_unlock_irq(sch->lock);
- put_device(&sch->dev);
+
return 0;
}
@@ -565,7 +543,8 @@
CIO_TRACE_EVENT(2, dbf_txt);
if (chp_get_status(chpid) != 0)
- for_each_subchannel(__chp_add, &chpid);
+ for_each_subchannel_staged(__chp_add, __chp_add_new_sch,
+ &chpid);
}
static void __s390_subchannel_vary_chpid(struct subchannel *sch,
@@ -616,25 +595,17 @@
spin_unlock_irqrestore(sch->lock, flags);
}
-static int s390_subchannel_vary_chpid_off(struct device *dev, void *data)
+static int s390_subchannel_vary_chpid_off(struct subchannel *sch, void *data)
{
- struct subchannel *sch;
- struct chp_id *chpid;
-
- sch = to_subchannel(dev);
- chpid = data;
+ struct chp_id *chpid = data;
__s390_subchannel_vary_chpid(sch, *chpid, 0);
return 0;
}
-static int s390_subchannel_vary_chpid_on(struct device *dev, void *data)
+static int s390_subchannel_vary_chpid_on(struct subchannel *sch, void *data)
{
- struct subchannel *sch;
- struct chp_id *chpid;
-
- sch = to_subchannel(dev);
- chpid = data;
+ struct chp_id *chpid = data;
__s390_subchannel_vary_chpid(sch, *chpid, 1);
return 0;
@@ -644,13 +615,7 @@
__s390_vary_chpid_on(struct subchannel_id schid, void *data)
{
struct schib schib;
- struct subchannel *sch;
- sch = get_subchannel_by_schid(schid);
- if (sch) {
- put_device(&sch->dev);
- return 0;
- }
if (stsch_err(schid, &schib))
/* We're through */
return -ENXIO;
@@ -670,12 +635,13 @@
* Redo PathVerification on the devices the chpid connects to
*/
- bus_for_each_dev(&css_bus_type, NULL, &chpid, on ?
- s390_subchannel_vary_chpid_on :
- s390_subchannel_vary_chpid_off);
if (on)
- /* Scan for new devices on varied on path. */
- for_each_subchannel(__s390_vary_chpid_on, NULL);
+ for_each_subchannel_staged(s390_subchannel_vary_chpid_on,
+ __s390_vary_chpid_on, &chpid);
+ else
+ for_each_subchannel_staged(s390_subchannel_vary_chpid_off,
+ NULL, &chpid);
+
return 0;
}