diff options
| -rw-r--r-- | arch/x86/kernel/cpu/intel_rdt_rdtgroup.c | 180 | ||||
| -rw-r--r-- | include/linux/sched.h | 3 |
2 files changed, 183 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c index e05a18685fc8..5cc0865f2908 100644 --- a/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c +++ b/arch/x86/kernel/cpu/intel_rdt_rdtgroup.c @@ -28,6 +28,7 @@ #include <linux/sched.h> #include <linux/slab.h> #include <linux/cpu.h> +#include <linux/task_work.h> #include <uapi/linux/magic.h> @@ -267,6 +268,162 @@ unlock: return ret ?: nbytes; } +struct task_move_callback { + struct callback_head work; + struct rdtgroup *rdtgrp; +}; + +static void move_myself(struct callback_head *head) +{ + struct task_move_callback *callback; + struct rdtgroup *rdtgrp; + + callback = container_of(head, struct task_move_callback, work); + rdtgrp = callback->rdtgrp; + + /* + * If resource group was deleted before this task work callback + * was invoked, then assign the task to root group and free the + * resource group. + */ + if (atomic_dec_and_test(&rdtgrp->waitcount) && + (rdtgrp->flags & RDT_DELETED)) { + current->closid = 0; + kfree(rdtgrp); + } + + kfree(callback); +} + +static int __rdtgroup_move_task(struct task_struct *tsk, + struct rdtgroup *rdtgrp) +{ + struct task_move_callback *callback; + int ret; + + callback = kzalloc(sizeof(*callback), GFP_KERNEL); + if (!callback) + return -ENOMEM; + callback->work.func = move_myself; + callback->rdtgrp = rdtgrp; + + /* + * Take a refcount, so rdtgrp cannot be freed before the + * callback has been invoked. + */ + atomic_inc(&rdtgrp->waitcount); + ret = task_work_add(tsk, &callback->work, true); + if (ret) { + /* + * Task is exiting. Drop the refcount and free the callback. + * No need to check the refcount as the group cannot be + * deleted before the write function unlocks rdtgroup_mutex. + */ + atomic_dec(&rdtgrp->waitcount); + kfree(callback); + } else { + tsk->closid = rdtgrp->closid; + } + return ret; +} + +static int rdtgroup_task_write_permission(struct task_struct *task, + struct kernfs_open_file *of) +{ + const struct cred *tcred = get_task_cred(task); + const struct cred *cred = current_cred(); + int ret = 0; + + /* + * Even if we're attaching all tasks in the thread group, we only + * need to check permissions on one of them. + */ + if (!uid_eq(cred->euid, GLOBAL_ROOT_UID) && + !uid_eq(cred->euid, tcred->uid) && + !uid_eq(cred->euid, tcred->suid)) + ret = -EPERM; + + put_cred(tcred); + return ret; +} + +static int rdtgroup_move_task(pid_t pid, struct rdtgroup *rdtgrp, + struct kernfs_open_file *of) +{ + struct task_struct *tsk; + int ret; + + rcu_read_lock(); + if (pid) { + tsk = find_task_by_vpid(pid); + if (!tsk) { + rcu_read_unlock(); + return -ESRCH; + } + } else { + tsk = current; + } + + get_task_struct(tsk); + rcu_read_unlock(); + + ret = rdtgroup_task_write_permission(tsk, of); + if (!ret) + ret = __rdtgroup_move_task(tsk, rdtgrp); + + put_task_struct(tsk); + return ret; +} + +static ssize_t rdtgroup_tasks_write(struct kernfs_open_file *of, + char *buf, size_t nbytes, loff_t off) +{ + struct rdtgroup *rdtgrp; + int ret = 0; + pid_t pid; + + if (kstrtoint(strstrip(buf), 0, &pid) || pid < 0) + return -EINVAL; + rdtgrp = rdtgroup_kn_lock_live(of->kn); + + if (rdtgrp) + ret = rdtgroup_move_task(pid, rdtgrp, of); + else + ret = -ENOENT; + + rdtgroup_kn_unlock(of->kn); + + return ret ?: nbytes; +} + +static void show_rdt_tasks(struct rdtgroup *r, struct seq_file *s) +{ + struct task_struct *p, *t; + + rcu_read_lock(); + for_each_process_thread(p, t) { + if (t->closid == r->closid) + seq_printf(s, "%d\n", t->pid); + } + rcu_read_unlock(); +} + +static int rdtgroup_tasks_show(struct kernfs_open_file *of, + struct seq_file *s, void *v) +{ + struct rdtgroup *rdtgrp; + int ret = 0; + + rdtgrp = rdtgroup_kn_lock_live(of->kn); + if (rdtgrp) + show_rdt_tasks(rdtgrp, s); + else + ret = -ENOENT; + rdtgroup_kn_unlock(of->kn); + + return ret; +} + /* Files in each rdtgroup */ static struct rftype rdtgroup_base_files[] = { { @@ -276,6 +433,13 @@ static struct rftype rdtgroup_base_files[] = { .write = rdtgroup_cpus_write, .seq_show = rdtgroup_cpus_show, }, + { + .name = "tasks", + .mode = 0644, + .kf_ops = &rdtgroup_kf_single_ops, + .write = rdtgroup_tasks_write, + .seq_show = rdtgroup_tasks_show, + }, }; static int rdt_num_closids_show(struct kernfs_open_file *of, @@ -592,6 +756,13 @@ static void rdt_reset_pqr_assoc_closid(void *v) static void rmdir_all_sub(void) { struct rdtgroup *rdtgrp, *tmp; + struct task_struct *p, *t; + + /* move all tasks to default resource group */ + read_lock(&tasklist_lock); + for_each_process_thread(p, t) + t->closid = 0; + read_unlock(&tasklist_lock); get_cpu(); /* Reset PQR_ASSOC MSR on this cpu. */ @@ -712,6 +883,7 @@ out_unlock: static int rdtgroup_rmdir(struct kernfs_node *kn) { + struct task_struct *p, *t; struct rdtgroup *rdtgrp; int cpu, ret = 0; @@ -721,6 +893,14 @@ static int rdtgroup_rmdir(struct kernfs_node *kn) return -ENOENT; } + /* Give any tasks back to the default group */ + read_lock(&tasklist_lock); + for_each_process_thread(p, t) { + if (t->closid == rdtgrp->closid) + t->closid = 0; + } + read_unlock(&tasklist_lock); + /* Give any CPUs back to the default group */ cpumask_or(&rdtgroup_default.cpu_mask, &rdtgroup_default.cpu_mask, &rdtgrp->cpu_mask); diff --git a/include/linux/sched.h b/include/linux/sched.h index 348f51b0ec92..c8f4152e7265 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1791,6 +1791,9 @@ struct task_struct { /* cg_list protected by css_set_lock and tsk->alloc_lock */ struct list_head cg_list; #endif +#ifdef CONFIG_INTEL_RDT_A + int closid; +#endif #ifdef CONFIG_FUTEX struct robust_list_head __user *robust_list; #ifdef CONFIG_COMPAT |