[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>
This commit is contained in:
Peter Oberparleiter
Martin Schwidefsky
parent
4beee64685
commit
e82a1567e4
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@ -136,17 +136,13 @@ static void terminate_internal_io(struct subchannel *sch)
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sch->driver->termination(sch);
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}
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static int
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s390_subchannel_remove_chpid(struct device *dev, void *data)
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static int s390_subchannel_remove_chpid(struct subchannel *sch, void *data)
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{
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int j;
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int mask;
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struct subchannel *sch;
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struct chp_id *chpid;
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struct chp_id *chpid = data;
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struct schib schib;
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sch = to_subchannel(dev);
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chpid = data;
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for (j = 0; j < 8; j++) {
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mask = 0x80 >> j;
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if ((sch->schib.pmcw.pim & mask) &&
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@ -202,12 +198,10 @@ void chsc_chp_offline(struct chp_id chpid)
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if (chp_get_status(chpid) <= 0)
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return;
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bus_for_each_dev(&css_bus_type, NULL, &chpid,
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s390_subchannel_remove_chpid);
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for_each_subchannel_staged(s390_subchannel_remove_chpid, NULL, &chpid);
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}
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static int
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s390_process_res_acc_new_sch(struct subchannel_id schid)
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static int s390_process_res_acc_new_sch(struct subchannel_id schid, void *data)
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{
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struct schib schib;
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/*
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@ -253,18 +247,10 @@ static int get_res_chpid_mask(struct chsc_ssd_info *ssd,
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return 0;
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}
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static int
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__s390_process_res_acc(struct subchannel_id schid, void *data)
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static int __s390_process_res_acc(struct subchannel *sch, void *data)
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{
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int chp_mask, old_lpm;
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struct res_acc_data *res_data;
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struct subchannel *sch;
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res_data = data;
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sch = get_subchannel_by_schid(schid);
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if (!sch)
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/* Check if a subchannel is newly available. */
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return s390_process_res_acc_new_sch(schid);
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struct res_acc_data *res_data = data;
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spin_lock_irq(sch->lock);
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chp_mask = get_res_chpid_mask(&sch->ssd_info, res_data);
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@ -283,7 +269,7 @@ __s390_process_res_acc(struct subchannel_id schid, void *data)
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sch->driver->verify(sch);
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out:
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spin_unlock_irq(sch->lock);
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put_device(&sch->dev);
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return 0;
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}
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@ -306,7 +292,8 @@ static void s390_process_res_acc (struct res_acc_data *res_data)
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* The more information we have (info), the less scanning
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* will we have to do.
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*/
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for_each_subchannel(__s390_process_res_acc, res_data);
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for_each_subchannel_staged(__s390_process_res_acc,
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s390_process_res_acc_new_sch, res_data);
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}
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static int
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@ -500,8 +487,7 @@ void chsc_process_crw(void)
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} while (sei_area->flags & 0x80);
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}
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static int
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__chp_add_new_sch(struct subchannel_id schid)
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static int __chp_add_new_sch(struct subchannel_id schid, void *data)
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{
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struct schib schib;
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@ -515,35 +501,27 @@ __chp_add_new_sch(struct subchannel_id schid)
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}
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static int
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__chp_add(struct subchannel_id schid, void *data)
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static int __chp_add(struct subchannel *sch, void *data)
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{
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int i, mask;
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struct chp_id *chpid;
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struct subchannel *sch;
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struct chp_id *chpid = data;
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chpid = data;
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sch = get_subchannel_by_schid(schid);
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if (!sch)
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/* Check if the subchannel is now available. */
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return __chp_add_new_sch(schid);
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spin_lock_irq(sch->lock);
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for (i=0; i<8; i++) {
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mask = 0x80 >> i;
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if ((sch->schib.pmcw.pim & mask) &&
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(sch->schib.pmcw.chpid[i] == chpid->id)) {
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if (stsch(sch->schid, &sch->schib) != 0) {
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/* Endgame. */
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spin_unlock_irq(sch->lock);
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return -ENXIO;
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}
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(sch->schib.pmcw.chpid[i] == chpid->id))
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break;
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}
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}
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if (i==8) {
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spin_unlock_irq(sch->lock);
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return 0;
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}
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if (stsch(sch->schid, &sch->schib)) {
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spin_unlock_irq(sch->lock);
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css_schedule_eval(sch->schid);
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return 0;
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}
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sch->lpm = ((sch->schib.pmcw.pim &
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sch->schib.pmcw.pam &
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sch->schib.pmcw.pom)
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@ -553,7 +531,7 @@ __chp_add(struct subchannel_id schid, void *data)
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sch->driver->verify(sch);
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spin_unlock_irq(sch->lock);
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put_device(&sch->dev);
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return 0;
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}
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@ -565,7 +543,8 @@ void chsc_chp_online(struct chp_id chpid)
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CIO_TRACE_EVENT(2, dbf_txt);
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if (chp_get_status(chpid) != 0)
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for_each_subchannel(__chp_add, &chpid);
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for_each_subchannel_staged(__chp_add, __chp_add_new_sch,
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&chpid);
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}
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static void __s390_subchannel_vary_chpid(struct subchannel *sch,
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@ -616,25 +595,17 @@ static void __s390_subchannel_vary_chpid(struct subchannel *sch,
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spin_unlock_irqrestore(sch->lock, flags);
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}
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static int s390_subchannel_vary_chpid_off(struct device *dev, void *data)
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static int s390_subchannel_vary_chpid_off(struct subchannel *sch, void *data)
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{
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struct subchannel *sch;
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struct chp_id *chpid;
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sch = to_subchannel(dev);
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chpid = data;
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struct chp_id *chpid = data;
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__s390_subchannel_vary_chpid(sch, *chpid, 0);
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return 0;
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}
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static int s390_subchannel_vary_chpid_on(struct device *dev, void *data)
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static int s390_subchannel_vary_chpid_on(struct subchannel *sch, void *data)
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{
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struct subchannel *sch;
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struct chp_id *chpid;
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sch = to_subchannel(dev);
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chpid = data;
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struct chp_id *chpid = data;
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__s390_subchannel_vary_chpid(sch, *chpid, 1);
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return 0;
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@ -644,13 +615,7 @@ static int
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__s390_vary_chpid_on(struct subchannel_id schid, void *data)
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{
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struct schib schib;
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struct subchannel *sch;
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sch = get_subchannel_by_schid(schid);
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if (sch) {
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put_device(&sch->dev);
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return 0;
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}
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if (stsch_err(schid, &schib))
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/* We're through */
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return -ENXIO;
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@ -670,12 +635,13 @@ int chsc_chp_vary(struct chp_id chpid, int on)
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* Redo PathVerification on the devices the chpid connects to
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*/
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bus_for_each_dev(&css_bus_type, NULL, &chpid, on ?
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s390_subchannel_vary_chpid_on :
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s390_subchannel_vary_chpid_off);
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if (on)
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/* Scan for new devices on varied on path. */
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for_each_subchannel(__s390_vary_chpid_on, NULL);
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for_each_subchannel_staged(s390_subchannel_vary_chpid_on,
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__s390_vary_chpid_on, &chpid);
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else
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for_each_subchannel_staged(s390_subchannel_vary_chpid_off,
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NULL, &chpid);
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return 0;
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}
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@ -51,6 +51,62 @@ for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data)
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return ret;
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}
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struct cb_data {
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void *data;
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struct idset *set;
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int (*fn_known_sch)(struct subchannel *, void *);
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int (*fn_unknown_sch)(struct subchannel_id, void *);
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};
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static int call_fn_known_sch(struct device *dev, void *data)
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{
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struct subchannel *sch = to_subchannel(dev);
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struct cb_data *cb = data;
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int rc = 0;
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idset_sch_del(cb->set, sch->schid);
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if (cb->fn_known_sch)
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rc = cb->fn_known_sch(sch, cb->data);
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return rc;
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}
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static int call_fn_unknown_sch(struct subchannel_id schid, void *data)
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{
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struct cb_data *cb = data;
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int rc = 0;
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if (idset_sch_contains(cb->set, schid))
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rc = cb->fn_unknown_sch(schid, cb->data);
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return rc;
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}
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int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
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int (*fn_unknown)(struct subchannel_id,
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void *), void *data)
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{
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struct cb_data cb;
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int rc;
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cb.set = idset_sch_new();
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if (!cb.set)
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return -ENOMEM;
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idset_fill(cb.set);
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cb.data = data;
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cb.fn_known_sch = fn_known;
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cb.fn_unknown_sch = fn_unknown;
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/* Process registered subchannels. */
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rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch);
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if (rc)
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goto out;
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/* Process unregistered subchannels. */
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if (fn_unknown)
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rc = for_each_subchannel(call_fn_unknown_sch, &cb);
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out:
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idset_free(cb.set);
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return rc;
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}
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static struct subchannel *
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css_alloc_subchannel(struct subchannel_id schid)
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{
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@ -402,20 +458,56 @@ static int __init slow_subchannel_init(void)
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return 0;
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}
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static int slow_eval_known_fn(struct subchannel *sch, void *data)
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{
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int eval;
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int rc;
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spin_lock_irq(&slow_subchannel_lock);
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eval = idset_sch_contains(slow_subchannel_set, sch->schid);
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idset_sch_del(slow_subchannel_set, sch->schid);
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spin_unlock_irq(&slow_subchannel_lock);
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if (eval) {
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rc = css_evaluate_known_subchannel(sch, 1);
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if (rc == -EAGAIN)
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css_schedule_eval(sch->schid);
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}
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return 0;
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}
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static int slow_eval_unknown_fn(struct subchannel_id schid, void *data)
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{
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int eval;
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int rc = 0;
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spin_lock_irq(&slow_subchannel_lock);
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eval = idset_sch_contains(slow_subchannel_set, schid);
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idset_sch_del(slow_subchannel_set, schid);
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spin_unlock_irq(&slow_subchannel_lock);
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if (eval) {
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rc = css_evaluate_new_subchannel(schid, 1);
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switch (rc) {
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case -EAGAIN:
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css_schedule_eval(schid);
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rc = 0;
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break;
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case -ENXIO:
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case -ENOMEM:
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case -EIO:
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/* These should abort looping */
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break;
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default:
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rc = 0;
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}
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}
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return rc;
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}
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static void css_slow_path_func(struct work_struct *unused)
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{
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struct subchannel_id schid;
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CIO_TRACE_EVENT(4, "slowpath");
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spin_lock_irq(&slow_subchannel_lock);
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init_subchannel_id(&schid);
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while (idset_sch_get_first(slow_subchannel_set, &schid)) {
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idset_sch_del(slow_subchannel_set, schid);
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spin_unlock_irq(&slow_subchannel_lock);
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css_evaluate_subchannel(schid, 1);
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spin_lock_irq(&slow_subchannel_lock);
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}
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spin_unlock_irq(&slow_subchannel_lock);
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for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn,
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NULL);
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}
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static DECLARE_WORK(slow_path_work, css_slow_path_func);
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@ -444,7 +536,6 @@ void css_schedule_eval_all(void)
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/* Reprobe subchannel if unregistered. */
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static int reprobe_subchannel(struct subchannel_id schid, void *data)
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{
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struct subchannel *sch;
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int ret;
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CIO_MSG_EVENT(6, "cio: reprobe 0.%x.%04x\n",
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@ -452,13 +543,6 @@ static int reprobe_subchannel(struct subchannel_id schid, void *data)
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if (need_reprobe)
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return -EAGAIN;
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sch = get_subchannel_by_schid(schid);
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if (sch) {
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/* Already known. */
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put_device(&sch->dev);
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return 0;
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}
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ret = css_probe_device(schid);
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switch (ret) {
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case 0:
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@ -486,7 +570,7 @@ static void reprobe_all(struct work_struct *unused)
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/* Make sure initial subchannel scan is done. */
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wait_event(ccw_device_init_wq,
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atomic_read(&ccw_device_init_count) == 0);
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ret = for_each_subchannel(reprobe_subchannel, NULL);
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ret = for_each_subchannel_staged(NULL, reprobe_subchannel, NULL);
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CIO_MSG_EVENT(2, "reprobe done (rc=%d, need_reprobe=%d)\n", ret,
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need_reprobe);
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@ -91,6 +91,9 @@ extern void css_driver_unregister(struct css_driver *);
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extern void css_sch_device_unregister(struct subchannel *);
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extern struct subchannel * get_subchannel_by_schid(struct subchannel_id);
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extern int css_init_done;
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int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *),
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int (*fn_unknown)(struct subchannel_id,
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void *), void *data);
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extern int for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *);
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extern void css_process_crw(int, int);
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extern void css_reiterate_subchannels(void);
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