From cee22a15052faa817e3ec8985a28154d3fabc7aa Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Mon, 8 Apr 2013 16:45:40 +0530 Subject: workqueues: Introduce new flag WQ_POWER_EFFICIENT for power oriented workqueues Workqueues can be performance or power-oriented. Currently, most workqueues are bound to the CPU they were created on. This gives good performance (due to cache effects) at the cost of potentially waking up otherwise idle cores (Idle from scheduler's perspective. Which may or may not be physically idle) just to process some work. To save power, we can allow the work to be rescheduled on a core that is already awake. Workqueues created with the WQ_UNBOUND flag will allow some power savings. However, we don't change the default behaviour of the system. To enable power-saving behaviour, a new config option CONFIG_WQ_POWER_EFFICIENT needs to be turned on. This option can also be overridden by the workqueue.power_efficient boot parameter. tj: Updated config description and comments. Renamed CONFIG_WQ_POWER_EFFICIENT to CONFIG_WQ_POWER_EFFICIENT_DEFAULT. Signed-off-by: Viresh Kumar Reviewed-by: Amit Kucheria Signed-off-by: Tejun Heo --- include/linux/workqueue.h | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) (limited to 'include/linux/workqueue.h') diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index 623488fdc1f..fc0136b604f 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -303,6 +303,33 @@ enum { WQ_CPU_INTENSIVE = 1 << 5, /* cpu instensive workqueue */ WQ_SYSFS = 1 << 6, /* visible in sysfs, see wq_sysfs_register() */ + /* + * Per-cpu workqueues are generally preferred because they tend to + * show better performance thanks to cache locality. Per-cpu + * workqueues exclude the scheduler from choosing the CPU to + * execute the worker threads, which has an unfortunate side effect + * of increasing power consumption. + * + * The scheduler considers a CPU idle if it doesn't have any task + * to execute and tries to keep idle cores idle to conserve power; + * however, for example, a per-cpu work item scheduled from an + * interrupt handler on an idle CPU will force the scheduler to + * excute the work item on that CPU breaking the idleness, which in + * turn may lead to more scheduling choices which are sub-optimal + * in terms of power consumption. + * + * Workqueues marked with WQ_POWER_EFFICIENT are per-cpu by default + * but become unbound if workqueue.power_efficient kernel param is + * specified. Per-cpu workqueues which are identified to + * contribute significantly to power-consumption are identified and + * marked with this flag and enabling the power_efficient mode + * leads to noticeable power saving at the cost of small + * performance disadvantage. + * + * http://thread.gmane.org/gmane.linux.kernel/1480396 + */ + WQ_POWER_EFFICIENT = 1 << 7, + __WQ_DRAINING = 1 << 16, /* internal: workqueue is draining */ __WQ_ORDERED = 1 << 17, /* internal: workqueue is ordered */ -- cgit v1.2.3-70-g09d2 From 0668106ca3865ba945e155097fb042bf66d364d3 Mon Sep 17 00:00:00 2001 From: Viresh Kumar Date: Wed, 24 Apr 2013 17:12:54 +0530 Subject: workqueue: Add system wide power_efficient workqueues This patch adds system wide workqueues aligned towards power saving. This is done by allocating them with WQ_UNBOUND flag if 'wq_power_efficient' is set to 'true'. tj: updated comments a bit. Signed-off-by: Viresh Kumar Signed-off-by: Tejun Heo --- include/linux/workqueue.h | 8 ++++++++ kernel/workqueue.c | 13 ++++++++++++- 2 files changed, 20 insertions(+), 1 deletion(-) (limited to 'include/linux/workqueue.h') diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index fc0136b604f..a9f4119c7e2 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -360,11 +360,19 @@ enum { * * system_freezable_wq is equivalent to system_wq except that it's * freezable. + * + * *_power_efficient_wq are inclined towards saving power and converted + * into WQ_UNBOUND variants if 'wq_power_efficient' is enabled; otherwise, + * they are same as their non-power-efficient counterparts - e.g. + * system_power_efficient_wq is identical to system_wq if + * 'wq_power_efficient' is disabled. See WQ_POWER_EFFICIENT for more info. */ extern struct workqueue_struct *system_wq; extern struct workqueue_struct *system_long_wq; extern struct workqueue_struct *system_unbound_wq; extern struct workqueue_struct *system_freezable_wq; +extern struct workqueue_struct *system_power_efficient_wq; +extern struct workqueue_struct *system_freezable_power_efficient_wq; static inline struct workqueue_struct * __deprecated __system_nrt_wq(void) { diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 8068d97ce14..16ca2d3dd29 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -314,6 +314,10 @@ struct workqueue_struct *system_unbound_wq __read_mostly; EXPORT_SYMBOL_GPL(system_unbound_wq); struct workqueue_struct *system_freezable_wq __read_mostly; EXPORT_SYMBOL_GPL(system_freezable_wq); +struct workqueue_struct *system_power_efficient_wq __read_mostly; +EXPORT_SYMBOL_GPL(system_power_efficient_wq); +struct workqueue_struct *system_freezable_power_efficient_wq __read_mostly; +EXPORT_SYMBOL_GPL(system_freezable_power_efficient_wq); static int worker_thread(void *__worker); static void copy_workqueue_attrs(struct workqueue_attrs *to, @@ -4987,8 +4991,15 @@ static int __init init_workqueues(void) WQ_UNBOUND_MAX_ACTIVE); system_freezable_wq = alloc_workqueue("events_freezable", WQ_FREEZABLE, 0); + system_power_efficient_wq = alloc_workqueue("events_power_efficient", + WQ_POWER_EFFICIENT, 0); + system_freezable_power_efficient_wq = alloc_workqueue("events_freezable_power_efficient", + WQ_FREEZABLE | WQ_POWER_EFFICIENT, + 0); BUG_ON(!system_wq || !system_highpri_wq || !system_long_wq || - !system_unbound_wq || !system_freezable_wq); + !system_unbound_wq || !system_freezable_wq || + !system_power_efficient_wq || + !system_freezable_power_efficient_wq); return 0; } early_initcall(init_workqueues); -- cgit v1.2.3-70-g09d2 From d8537548c924db3c44afde7646b6e220c7beb79d Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Wed, 3 Jul 2013 15:04:57 -0700 Subject: drivers: avoid format strings in names passed to alloc_workqueue() For the workqueue creation interfaces that do not expect format strings, make sure they cannot accidently be parsed that way. Additionally, clean up calls made with a single parameter that would be handled as a format string. Many callers are passing potentially dynamic string content, so use "%s" in those cases to avoid any potential accidents. Signed-off-by: Kees Cook Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- crypto/pcrypt.c | 4 ++-- drivers/media/pci/cx18/cx18-driver.c | 2 +- drivers/message/i2o/driver.c | 4 ++-- drivers/net/wireless/rt2x00/rt2x00dev.c | 2 +- drivers/net/wireless/rtlwifi/base.c | 2 +- drivers/pci/hotplug/pciehp_hpc.c | 4 +--- drivers/pci/hotplug/shpchp_core.c | 3 +-- drivers/scsi/be2iscsi/be_main.c | 2 +- drivers/scsi/qla4xxx/ql4_os.c | 4 ++-- drivers/scsi/scsi_transport_fc.c | 6 +++--- include/linux/workqueue.h | 7 ++++--- net/bluetooth/hci_core.c | 9 ++++----- net/mac80211/main.c | 2 +- 13 files changed, 24 insertions(+), 27 deletions(-) (limited to 'include/linux/workqueue.h') diff --git a/crypto/pcrypt.c b/crypto/pcrypt.c index b2c99dc1c5e..f8c920cafe6 100644 --- a/crypto/pcrypt.c +++ b/crypto/pcrypt.c @@ -455,8 +455,8 @@ static int pcrypt_init_padata(struct padata_pcrypt *pcrypt, get_online_cpus(); - pcrypt->wq = alloc_workqueue(name, - WQ_MEM_RECLAIM | WQ_CPU_INTENSIVE, 1); + pcrypt->wq = alloc_workqueue("%s", WQ_MEM_RECLAIM | WQ_CPU_INTENSIVE, + 1, name); if (!pcrypt->wq) goto err; diff --git a/drivers/media/pci/cx18/cx18-driver.c b/drivers/media/pci/cx18/cx18-driver.c index 67b61cf3e03..004d8ace501 100644 --- a/drivers/media/pci/cx18/cx18-driver.c +++ b/drivers/media/pci/cx18/cx18-driver.c @@ -695,7 +695,7 @@ static int cx18_create_in_workq(struct cx18 *cx) { snprintf(cx->in_workq_name, sizeof(cx->in_workq_name), "%s-in", cx->v4l2_dev.name); - cx->in_work_queue = alloc_ordered_workqueue(cx->in_workq_name, 0); + cx->in_work_queue = alloc_ordered_workqueue("%s", 0, cx->in_workq_name); if (cx->in_work_queue == NULL) { CX18_ERR("Unable to create incoming mailbox handler thread\n"); return -ENOMEM; diff --git a/drivers/message/i2o/driver.c b/drivers/message/i2o/driver.c index 8a5b2d8f4da..813eaa33fa1 100644 --- a/drivers/message/i2o/driver.c +++ b/drivers/message/i2o/driver.c @@ -84,8 +84,8 @@ int i2o_driver_register(struct i2o_driver *drv) osm_debug("Register driver %s\n", drv->name); if (drv->event) { - drv->event_queue = alloc_workqueue(drv->name, - WQ_MEM_RECLAIM, 1); + drv->event_queue = alloc_workqueue("%s", WQ_MEM_RECLAIM, 1, + drv->name); if (!drv->event_queue) { osm_err("Could not initialize event queue for driver " "%s\n", drv->name); diff --git a/drivers/net/wireless/rt2x00/rt2x00dev.c b/drivers/net/wireless/rt2x00/rt2x00dev.c index 90dc1433698..c8b9ef0c21f 100644 --- a/drivers/net/wireless/rt2x00/rt2x00dev.c +++ b/drivers/net/wireless/rt2x00/rt2x00dev.c @@ -1321,7 +1321,7 @@ int rt2x00lib_probe_dev(struct rt2x00_dev *rt2x00dev) * Initialize work. */ rt2x00dev->workqueue = - alloc_ordered_workqueue(wiphy_name(rt2x00dev->hw->wiphy), 0); + alloc_ordered_workqueue("%s", 0, wiphy_name(rt2x00dev->hw->wiphy)); if (!rt2x00dev->workqueue) { retval = -ENOMEM; goto exit; diff --git a/drivers/net/wireless/rtlwifi/base.c b/drivers/net/wireless/rtlwifi/base.c index af59dd5718e..a5f223145b0 100644 --- a/drivers/net/wireless/rtlwifi/base.c +++ b/drivers/net/wireless/rtlwifi/base.c @@ -380,7 +380,7 @@ static void _rtl_init_deferred_work(struct ieee80211_hw *hw) /* <2> work queue */ rtlpriv->works.hw = hw; - rtlpriv->works.rtl_wq = alloc_workqueue(rtlpriv->cfg->name, 0, 0); + rtlpriv->works.rtl_wq = alloc_workqueue("%s", 0, 0, rtlpriv->cfg->name); INIT_DELAYED_WORK(&rtlpriv->works.watchdog_wq, (void *)rtl_watchdog_wq_callback); INIT_DELAYED_WORK(&rtlpriv->works.ips_nic_off_wq, diff --git a/drivers/pci/hotplug/pciehp_hpc.c b/drivers/pci/hotplug/pciehp_hpc.c index 5127f3f4182..b2255736ac8 100644 --- a/drivers/pci/hotplug/pciehp_hpc.c +++ b/drivers/pci/hotplug/pciehp_hpc.c @@ -773,14 +773,12 @@ static void pcie_shutdown_notification(struct controller *ctrl) static int pcie_init_slot(struct controller *ctrl) { struct slot *slot; - char name[32]; slot = kzalloc(sizeof(*slot), GFP_KERNEL); if (!slot) return -ENOMEM; - snprintf(name, sizeof(name), "pciehp-%u", PSN(ctrl)); - slot->wq = alloc_workqueue(name, 0, 0); + slot->wq = alloc_workqueue("pciehp-%u", 0, 0, PSN(ctrl)); if (!slot->wq) goto abort; diff --git a/drivers/pci/hotplug/shpchp_core.c b/drivers/pci/hotplug/shpchp_core.c index 3100c52c837..d3f757df691 100644 --- a/drivers/pci/hotplug/shpchp_core.c +++ b/drivers/pci/hotplug/shpchp_core.c @@ -128,8 +128,7 @@ static int init_slots(struct controller *ctrl) slot->hpc_ops = ctrl->hpc_ops; slot->number = ctrl->first_slot + (ctrl->slot_num_inc * i); - snprintf(name, sizeof(name), "shpchp-%d", slot->number); - slot->wq = alloc_workqueue(name, 0, 0); + slot->wq = alloc_workqueue("shpchp-%d", 0, 0, slot->number); if (!slot->wq) { retval = -ENOMEM; goto error_info; diff --git a/drivers/scsi/be2iscsi/be_main.c b/drivers/scsi/be2iscsi/be_main.c index d24a2867bc2..a1f5ac7a980 100644 --- a/drivers/scsi/be2iscsi/be_main.c +++ b/drivers/scsi/be2iscsi/be_main.c @@ -4996,7 +4996,7 @@ static int beiscsi_dev_probe(struct pci_dev *pcidev, snprintf(phba->wq_name, sizeof(phba->wq_name), "beiscsi_%02x_wq", phba->shost->host_no); - phba->wq = alloc_workqueue(phba->wq_name, WQ_MEM_RECLAIM, 1); + phba->wq = alloc_workqueue("%s", WQ_MEM_RECLAIM, 1, phba->wq_name); if (!phba->wq) { beiscsi_log(phba, KERN_ERR, BEISCSI_LOG_INIT, "BM_%d : beiscsi_dev_probe-" diff --git a/drivers/scsi/qla4xxx/ql4_os.c b/drivers/scsi/qla4xxx/ql4_os.c index 4d231c12463..b246b3c2691 100644 --- a/drivers/scsi/qla4xxx/ql4_os.c +++ b/drivers/scsi/qla4xxx/ql4_os.c @@ -7060,8 +7060,8 @@ skip_retry_init: } INIT_WORK(&ha->dpc_work, qla4xxx_do_dpc); - sprintf(buf, "qla4xxx_%lu_task", ha->host_no); - ha->task_wq = alloc_workqueue(buf, WQ_MEM_RECLAIM, 1); + ha->task_wq = alloc_workqueue("qla4xxx_%lu_task", WQ_MEM_RECLAIM, 1, + ha->host_no); if (!ha->task_wq) { ql4_printk(KERN_WARNING, ha, "Unable to start task thread!\n"); ret = -ENODEV; diff --git a/drivers/scsi/scsi_transport_fc.c b/drivers/scsi/scsi_transport_fc.c index e106c276aa0..4628fd5e068 100644 --- a/drivers/scsi/scsi_transport_fc.c +++ b/drivers/scsi/scsi_transport_fc.c @@ -435,7 +435,7 @@ static int fc_host_setup(struct transport_container *tc, struct device *dev, snprintf(fc_host->work_q_name, sizeof(fc_host->work_q_name), "fc_wq_%d", shost->host_no); - fc_host->work_q = alloc_workqueue(fc_host->work_q_name, 0, 0); + fc_host->work_q = alloc_workqueue("%s", 0, 0, fc_host->work_q_name); if (!fc_host->work_q) return -ENOMEM; @@ -443,8 +443,8 @@ static int fc_host_setup(struct transport_container *tc, struct device *dev, snprintf(fc_host->devloss_work_q_name, sizeof(fc_host->devloss_work_q_name), "fc_dl_%d", shost->host_no); - fc_host->devloss_work_q = - alloc_workqueue(fc_host->devloss_work_q_name, 0, 0); + fc_host->devloss_work_q = alloc_workqueue("%s", 0, 0, + fc_host->devloss_work_q_name); if (!fc_host->devloss_work_q) { destroy_workqueue(fc_host->work_q); fc_host->work_q = NULL; diff --git a/include/linux/workqueue.h b/include/linux/workqueue.h index a9f4119c7e2..a0ed78ab54d 100644 --- a/include/linux/workqueue.h +++ b/include/linux/workqueue.h @@ -445,11 +445,12 @@ __alloc_workqueue_key(const char *fmt, unsigned int flags, int max_active, alloc_workqueue(fmt, WQ_UNBOUND | __WQ_ORDERED | (flags), 1, ##args) #define create_workqueue(name) \ - alloc_workqueue((name), WQ_MEM_RECLAIM, 1) + alloc_workqueue("%s", WQ_MEM_RECLAIM, 1, (name)) #define create_freezable_workqueue(name) \ - alloc_workqueue((name), WQ_FREEZABLE | WQ_UNBOUND | WQ_MEM_RECLAIM, 1) + alloc_workqueue("%s", WQ_FREEZABLE | WQ_UNBOUND | WQ_MEM_RECLAIM, \ + 1, (name)) #define create_singlethread_workqueue(name) \ - alloc_workqueue((name), WQ_UNBOUND | WQ_MEM_RECLAIM, 1) + alloc_workqueue("%s", WQ_UNBOUND | WQ_MEM_RECLAIM, 1, (name)) extern void destroy_workqueue(struct workqueue_struct *wq); diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index ace5e55fe5a..db7de80b88a 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -2211,16 +2211,15 @@ int hci_register_dev(struct hci_dev *hdev) list_add(&hdev->list, &hci_dev_list); write_unlock(&hci_dev_list_lock); - hdev->workqueue = alloc_workqueue(hdev->name, WQ_HIGHPRI | WQ_UNBOUND | - WQ_MEM_RECLAIM, 1); + hdev->workqueue = alloc_workqueue("%s", WQ_HIGHPRI | WQ_UNBOUND | + WQ_MEM_RECLAIM, 1, hdev->name); if (!hdev->workqueue) { error = -ENOMEM; goto err; } - hdev->req_workqueue = alloc_workqueue(hdev->name, - WQ_HIGHPRI | WQ_UNBOUND | - WQ_MEM_RECLAIM, 1); + hdev->req_workqueue = alloc_workqueue("%s", WQ_HIGHPRI | WQ_UNBOUND | + WQ_MEM_RECLAIM, 1, hdev->name); if (!hdev->req_workqueue) { destroy_workqueue(hdev->workqueue); error = -ENOMEM; diff --git a/net/mac80211/main.c b/net/mac80211/main.c index 8a7bfc47d57..8eae74ac4e1 100644 --- a/net/mac80211/main.c +++ b/net/mac80211/main.c @@ -921,7 +921,7 @@ int ieee80211_register_hw(struct ieee80211_hw *hw) hw->queues = IEEE80211_MAX_QUEUES; local->workqueue = - alloc_ordered_workqueue(wiphy_name(local->hw.wiphy), 0); + alloc_ordered_workqueue("%s", 0, wiphy_name(local->hw.wiphy)); if (!local->workqueue) { result = -ENOMEM; goto fail_workqueue; -- cgit v1.2.3-70-g09d2