diff options
Diffstat (limited to 'arch/x86/kernel/cpu')
| -rw-r--r-- | arch/x86/kernel/cpu/intel_rdt.h | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c | 85 |
2 files changed, 85 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/intel_rdt.h b/arch/x86/kernel/cpu/intel_rdt.h index b8e490a43290..2d9cbb9d7a58 100644 --- a/arch/x86/kernel/cpu/intel_rdt.h +++ b/arch/x86/kernel/cpu/intel_rdt.h @@ -142,6 +142,7 @@ struct mongroup { * region * @debugfs_dir: pointer to this region's directory in the debugfs * filesystem + * @pm_reqs: Power management QoS requests related to this region */ struct pseudo_lock_region { struct rdt_resource *r; @@ -155,6 +156,7 @@ struct pseudo_lock_region { void *kmem; unsigned int minor; struct dentry *debugfs_dir; + struct list_head pm_reqs; }; /** diff --git a/arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c b/arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c index dd1341557c9d..6e83f61552a5 100644 --- a/arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c +++ b/arch/x86/kernel/cpu/intel_rdt_pseudo_lock.c @@ -17,6 +17,7 @@ #include <linux/debugfs.h> #include <linux/kthread.h> #include <linux/mman.h> +#include <linux/pm_qos.h> #include <linux/slab.h> #include <linux/uaccess.h> @@ -176,6 +177,76 @@ static struct rdtgroup *region_find_by_minor(unsigned int minor) } /** + * pseudo_lock_pm_req - A power management QoS request list entry + * @list: Entry within the @pm_reqs list for a pseudo-locked region + * @req: PM QoS request + */ +struct pseudo_lock_pm_req { + struct list_head list; + struct dev_pm_qos_request req; +}; + +static void pseudo_lock_cstates_relax(struct pseudo_lock_region *plr) +{ + struct pseudo_lock_pm_req *pm_req, *next; + + list_for_each_entry_safe(pm_req, next, &plr->pm_reqs, list) { + dev_pm_qos_remove_request(&pm_req->req); + list_del(&pm_req->list); + kfree(pm_req); + } +} + +/** + * pseudo_lock_cstates_constrain - Restrict cores from entering C6 + * + * To prevent the cache from being affected by power management entering + * C6 has to be avoided. This is accomplished by requesting a latency + * requirement lower than lowest C6 exit latency of all supported + * platforms as found in the cpuidle state tables in the intel_idle driver. + * At this time it is possible to do so with a single latency requirement + * for all supported platforms. + * + * Since Goldmont is supported, which is affected by X86_BUG_MONITOR, + * the ACPI latencies need to be considered while keeping in mind that C2 + * may be set to map to deeper sleep states. In this case the latency + * requirement needs to prevent entering C2 also. + */ +static int pseudo_lock_cstates_constrain(struct pseudo_lock_region *plr) +{ + struct pseudo_lock_pm_req *pm_req; + int cpu; + int ret; + + for_each_cpu(cpu, &plr->d->cpu_mask) { + pm_req = kzalloc(sizeof(*pm_req), GFP_KERNEL); + if (!pm_req) { + rdt_last_cmd_puts("fail allocating mem for PM QoS\n"); + ret = -ENOMEM; + goto out_err; + } + ret = dev_pm_qos_add_request(get_cpu_device(cpu), + &pm_req->req, + DEV_PM_QOS_RESUME_LATENCY, + 30); + if (ret < 0) { + rdt_last_cmd_printf("fail to add latency req cpu%d\n", + cpu); + kfree(pm_req); + ret = -1; + goto out_err; + } + list_add(&pm_req->list, &plr->pm_reqs); + } + + return 0; + +out_err: + pseudo_lock_cstates_relax(plr); + return ret; +} + +/** * pseudo_lock_region_init - Initialize pseudo-lock region information * @plr: pseudo-lock region * @@ -242,6 +313,7 @@ static int pseudo_lock_init(struct rdtgroup *rdtgrp) return -ENOMEM; init_waitqueue_head(&plr->lock_thread_wq); + INIT_LIST_HEAD(&plr->pm_reqs); rdtgrp->plr = plr; return 0; } @@ -1135,6 +1207,12 @@ int rdtgroup_pseudo_lock_create(struct rdtgroup *rdtgrp) if (ret < 0) return ret; + ret = pseudo_lock_cstates_constrain(plr); + if (ret < 0) { + ret = -EINVAL; + goto out_region; + } + plr->thread_done = 0; thread = kthread_create_on_node(pseudo_lock_fn, rdtgrp, @@ -1143,7 +1221,7 @@ int rdtgroup_pseudo_lock_create(struct rdtgroup *rdtgrp) if (IS_ERR(thread)) { ret = PTR_ERR(thread); rdt_last_cmd_printf("locking thread returned error %d\n", ret); - goto out_region; + goto out_cstates; } kthread_bind(thread, plr->cpu); @@ -1161,7 +1239,7 @@ int rdtgroup_pseudo_lock_create(struct rdtgroup *rdtgrp) * empty pseudo-locking loop. */ rdt_last_cmd_puts("locking thread interrupted\n"); - goto out_region; + goto out_cstates; } if (!IS_ERR_OR_NULL(debugfs_resctrl)) { @@ -1222,6 +1300,8 @@ out_minor: pseudo_lock_minor_release(new_minor); out_debugfs: debugfs_remove_recursive(plr->debugfs_dir); +out_cstates: + pseudo_lock_cstates_relax(plr); out_region: pseudo_lock_region_clear(plr); out: @@ -1255,6 +1335,7 @@ void rdtgroup_pseudo_lock_remove(struct rdtgroup *rdtgrp) goto free; } + pseudo_lock_cstates_relax(plr); debugfs_remove_recursive(rdtgrp->plr->debugfs_dir); device_destroy(pseudo_lock_class, MKDEV(pseudo_lock_major, plr->minor)); pseudo_lock_minor_release(plr->minor); |