From: Peter Oberparleiter Date: Sat, 26 Jan 2008 13:10:48 +0000 (+0100) Subject: [S390] cio: reduce cpu utilization during device scan X-Git-Tag: v2.6.25-rc1~1228^2~43 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e82a1567e4b22eb035da2499d20ddd573c9acf75;p=linux-2.6 [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 Signed-off-by: Martin Schwidefsky --- diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c index 12a344c66b..93e6f74187 100644 --- a/drivers/s390/cio/chsc.c +++ b/drivers/s390/cio/chsc.c @@ -136,17 +136,13 @@ static void terminate_internal_io(struct subchannel *sch) 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 @@ void chsc_chp_offline(struct chp_id chpid) 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 @@ static int get_res_chpid_mask(struct chsc_ssd_info *ssd, 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 @@ __s390_process_res_acc(struct subchannel_id schid, void *data) sch->driver->verify(sch); out: spin_unlock_irq(sch->lock); - put_device(&sch->dev); + return 0; } @@ -306,7 +292,8 @@ static void s390_process_res_acc (struct res_acc_data *res_data) * 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 @@ void chsc_process_crw(void) } 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 @@ __chp_add_new_sch(struct subchannel_id schid) } -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; - - chpid = data; - sch = get_subchannel_by_schid(schid); - if (!sch) - /* Check if the subchannel is now available. */ - return __chp_add_new_sch(schid); + struct chp_id *chpid = data; + 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 @@ __chp_add(struct subchannel_id schid, void *data) sch->driver->verify(sch); spin_unlock_irq(sch->lock); - put_device(&sch->dev); + return 0; } @@ -565,7 +543,8 @@ void chsc_chp_online(struct chp_id chpid) 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 @@ static void __s390_subchannel_vary_chpid(struct subchannel *sch, 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 @@ static int __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 @@ int chsc_chp_vary(struct chp_id chpid, int on) * 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; } diff --git a/drivers/s390/cio/css.c b/drivers/s390/cio/css.c index 69d56c7284..3b45bbe6cc 100644 --- a/drivers/s390/cio/css.c +++ b/drivers/s390/cio/css.c @@ -51,6 +51,62 @@ for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *data) return ret; } +struct cb_data { + void *data; + struct idset *set; + int (*fn_known_sch)(struct subchannel *, void *); + int (*fn_unknown_sch)(struct subchannel_id, void *); +}; + +static int call_fn_known_sch(struct device *dev, void *data) +{ + struct subchannel *sch = to_subchannel(dev); + struct cb_data *cb = data; + int rc = 0; + + idset_sch_del(cb->set, sch->schid); + if (cb->fn_known_sch) + rc = cb->fn_known_sch(sch, cb->data); + return rc; +} + +static int call_fn_unknown_sch(struct subchannel_id schid, void *data) +{ + struct cb_data *cb = data; + int rc = 0; + + if (idset_sch_contains(cb->set, schid)) + rc = cb->fn_unknown_sch(schid, cb->data); + return rc; +} + +int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *), + int (*fn_unknown)(struct subchannel_id, + void *), void *data) +{ + struct cb_data cb; + int rc; + + cb.set = idset_sch_new(); + if (!cb.set) + return -ENOMEM; + idset_fill(cb.set); + cb.data = data; + cb.fn_known_sch = fn_known; + cb.fn_unknown_sch = fn_unknown; + /* Process registered subchannels. */ + rc = bus_for_each_dev(&css_bus_type, NULL, &cb, call_fn_known_sch); + if (rc) + goto out; + /* Process unregistered subchannels. */ + if (fn_unknown) + rc = for_each_subchannel(call_fn_unknown_sch, &cb); +out: + idset_free(cb.set); + + return rc; +} + static struct subchannel * css_alloc_subchannel(struct subchannel_id schid) { @@ -402,20 +458,56 @@ static int __init slow_subchannel_init(void) return 0; } -static void css_slow_path_func(struct work_struct *unused) +static int slow_eval_known_fn(struct subchannel *sch, void *data) { - struct subchannel_id schid; + int eval; + int rc; - CIO_TRACE_EVENT(4, "slowpath"); spin_lock_irq(&slow_subchannel_lock); - init_subchannel_id(&schid); - while (idset_sch_get_first(slow_subchannel_set, &schid)) { - idset_sch_del(slow_subchannel_set, schid); - spin_unlock_irq(&slow_subchannel_lock); - css_evaluate_subchannel(schid, 1); - spin_lock_irq(&slow_subchannel_lock); + eval = idset_sch_contains(slow_subchannel_set, sch->schid); + idset_sch_del(slow_subchannel_set, sch->schid); + spin_unlock_irq(&slow_subchannel_lock); + if (eval) { + rc = css_evaluate_known_subchannel(sch, 1); + if (rc == -EAGAIN) + css_schedule_eval(sch->schid); } + return 0; +} + +static int slow_eval_unknown_fn(struct subchannel_id schid, void *data) +{ + int eval; + int rc = 0; + + spin_lock_irq(&slow_subchannel_lock); + eval = idset_sch_contains(slow_subchannel_set, schid); + idset_sch_del(slow_subchannel_set, schid); spin_unlock_irq(&slow_subchannel_lock); + if (eval) { + rc = css_evaluate_new_subchannel(schid, 1); + switch (rc) { + case -EAGAIN: + css_schedule_eval(schid); + rc = 0; + break; + case -ENXIO: + case -ENOMEM: + case -EIO: + /* These should abort looping */ + break; + default: + rc = 0; + } + } + return rc; +} + +static void css_slow_path_func(struct work_struct *unused) +{ + CIO_TRACE_EVENT(4, "slowpath"); + for_each_subchannel_staged(slow_eval_known_fn, slow_eval_unknown_fn, + NULL); } static DECLARE_WORK(slow_path_work, css_slow_path_func); @@ -444,7 +536,6 @@ void css_schedule_eval_all(void) /* Reprobe subchannel if unregistered. */ static int reprobe_subchannel(struct subchannel_id schid, void *data) { - struct subchannel *sch; int ret; CIO_MSG_EVENT(6, "cio: reprobe 0.%x.%04x\n", @@ -452,13 +543,6 @@ static int reprobe_subchannel(struct subchannel_id schid, void *data) if (need_reprobe) return -EAGAIN; - sch = get_subchannel_by_schid(schid); - if (sch) { - /* Already known. */ - put_device(&sch->dev); - return 0; - } - ret = css_probe_device(schid); switch (ret) { case 0: @@ -486,7 +570,7 @@ static void reprobe_all(struct work_struct *unused) /* Make sure initial subchannel scan is done. */ wait_event(ccw_device_init_wq, atomic_read(&ccw_device_init_count) == 0); - ret = for_each_subchannel(reprobe_subchannel, NULL); + ret = for_each_subchannel_staged(NULL, reprobe_subchannel, NULL); CIO_MSG_EVENT(2, "reprobe done (rc=%d, need_reprobe=%d)\n", ret, need_reprobe); diff --git a/drivers/s390/cio/css.h b/drivers/s390/cio/css.h index 40598b8ee2..b705545235 100644 --- a/drivers/s390/cio/css.h +++ b/drivers/s390/cio/css.h @@ -91,6 +91,9 @@ extern void css_driver_unregister(struct css_driver *); extern void css_sch_device_unregister(struct subchannel *); extern struct subchannel * get_subchannel_by_schid(struct subchannel_id); extern int css_init_done; +int for_each_subchannel_staged(int (*fn_known)(struct subchannel *, void *), + int (*fn_unknown)(struct subchannel_id, + void *), void *data); extern int for_each_subchannel(int(*fn)(struct subchannel_id, void *), void *); extern void css_process_crw(int, int); extern void css_reiterate_subchannels(void);