--- /dev/null
+/*
+ * General MIPS MT support routines, usable in AP/SP and SMVP.
+ * Copyright (C) 2005 Mips Technologies, Inc
+ */
+#include <linux/cpu.h>
+#include <linux/cpuset.h>
+#include <linux/cpumask.h>
+#include <linux/delay.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/sched.h>
+#include <linux/security.h>
+#include <linux/types.h>
+#include <asm/uaccess.h>
+
+/*
+ * CPU mask used to set process affinity for MT VPEs/TCs with FPUs
+ */
+cpumask_t mt_fpu_cpumask;
+
+static int fpaff_threshold = -1;
+unsigned long mt_fpemul_threshold;
+
+/*
+ * Replacement functions for the sys_sched_setaffinity() and
+ * sys_sched_getaffinity() system calls, so that we can integrate
+ * FPU affinity with the user's requested processor affinity.
+ * This code is 98% identical with the sys_sched_setaffinity()
+ * and sys_sched_getaffinity() system calls, and should be
+ * updated when kernel/sched/core.c changes.
+ */
+
+/*
+ * find_process_by_pid - find a process with a matching PID value.
+ * used in sys_sched_set/getaffinity() in kernel/sched/core.c, so
+ * cloned here.
+ */
+static inline struct task_struct *find_process_by_pid(pid_t pid)
+{
+ return pid ? find_task_by_vpid(pid) : current;
+}
+
+/*
+ * check the target process has a UID that matches the current process's
+ */
+static bool check_same_owner(struct task_struct *p)
+{
+ const struct cred *cred = current_cred(), *pcred;
+ bool match;
+
+ rcu_read_lock();
+ pcred = __task_cred(p);
+ match = (uid_eq(cred->euid, pcred->euid) ||
+ uid_eq(cred->euid, pcred->uid));
+ rcu_read_unlock();
+ return match;
+}
+
+/*
+ * mipsmt_sys_sched_setaffinity - set the cpu affinity of a process
+ */
+asmlinkage long mipsmt_sys_sched_setaffinity(pid_t pid, unsigned int len,
+ unsigned long __user *user_mask_ptr)
+{
+ cpumask_var_t cpus_allowed, new_mask, effective_mask;
+ struct thread_info *ti;
+ struct task_struct *p;
+ int retval;
+
+ if (len < sizeof(new_mask))
+ return -EINVAL;
+
+ if (copy_from_user(&new_mask, user_mask_ptr, sizeof(new_mask)))
+ return -EFAULT;
+
+ get_online_cpus();
+ rcu_read_lock();
+
+ p = find_process_by_pid(pid);
+ if (!p) {
+ rcu_read_unlock();
+ put_online_cpus();
+ return -ESRCH;
+ }
+
+ /* Prevent p going away */
+ get_task_struct(p);
+ rcu_read_unlock();
+
+ if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
+ retval = -ENOMEM;
+ goto out_put_task;
+ }
+ if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
+ retval = -ENOMEM;
+ goto out_free_cpus_allowed;
+ }
+ if (!alloc_cpumask_var(&effective_mask, GFP_KERNEL)) {
+ retval = -ENOMEM;
+ goto out_free_new_mask;
+ }
+ retval = -EPERM;
+ if (!check_same_owner(p) && !capable(CAP_SYS_NICE))
+ goto out_unlock;
+
+ retval = security_task_setscheduler(p);
+ if (retval)
+ goto out_unlock;
+
+ /* Record new user-specified CPU set for future reference */
+ cpumask_copy(&p->thread.user_cpus_allowed, new_mask);
+
+ again:
+ /* Compute new global allowed CPU set if necessary */
+ ti = task_thread_info(p);
+ if (test_ti_thread_flag(ti, TIF_FPUBOUND) &&
+ cpumask_intersects(new_mask, &mt_fpu_cpumask)) {
+ cpumask_and(effective_mask, new_mask, &mt_fpu_cpumask);
+ retval = set_cpus_allowed_ptr(p, effective_mask);
+ } else {
+ cpumask_copy(effective_mask, new_mask);
+ clear_ti_thread_flag(ti, TIF_FPUBOUND);
+ retval = set_cpus_allowed_ptr(p, new_mask);
+ }
+
+ if (!retval) {
+ cpuset_cpus_allowed(p, cpus_allowed);
+ if (!cpumask_subset(effective_mask, cpus_allowed)) {
+ /*
+ * We must have raced with a concurrent cpuset
+ * update. Just reset the cpus_allowed to the
+ * cpuset's cpus_allowed
+ */
+ cpumask_copy(new_mask, cpus_allowed);
+ goto again;
+ }
+ }
+out_unlock:
+ free_cpumask_var(effective_mask);
+out_free_new_mask:
+ free_cpumask_var(new_mask);
+out_free_cpus_allowed:
+ free_cpumask_var(cpus_allowed);
+out_put_task:
+ put_task_struct(p);
+ put_online_cpus();
+ return retval;
+}
+
+/*
+ * mipsmt_sys_sched_getaffinity - get the cpu affinity of a process
+ */
+asmlinkage long mipsmt_sys_sched_getaffinity(pid_t pid, unsigned int len,
+ unsigned long __user *user_mask_ptr)
+{
+ unsigned int real_len;
+ cpumask_t mask;
+ int retval;
+ struct task_struct *p;
+
+ real_len = sizeof(mask);
+ if (len < real_len)
+ return -EINVAL;
+
+ get_online_cpus();
+ read_lock(&tasklist_lock);
+
+ retval = -ESRCH;
+ p = find_process_by_pid(pid);
+ if (!p)
+ goto out_unlock;
+ retval = security_task_getscheduler(p);
+ if (retval)
+ goto out_unlock;
+
+ cpumask_and(&mask, &p->thread.user_cpus_allowed, cpu_possible_mask);
+
+out_unlock:
+ read_unlock(&tasklist_lock);
+ put_online_cpus();
+ if (retval)
+ return retval;
+ if (copy_to_user(user_mask_ptr, &mask, real_len))
+ return -EFAULT;
+ return real_len;
+}
+
+
+static int __init fpaff_thresh(char *str)
+{
+ get_option(&str, &fpaff_threshold);
+ return 1;
+}
+__setup("fpaff=", fpaff_thresh);
+
+/*
+ * FPU Use Factor empirically derived from experiments on 34K
+ */
+#define FPUSEFACTOR 2000
+
+static __init int mt_fp_affinity_init(void)
+{
+ if (fpaff_threshold >= 0) {
+ mt_fpemul_threshold = fpaff_threshold;
+ } else {
+ mt_fpemul_threshold =
+ (FPUSEFACTOR * (loops_per_jiffy/(500000/HZ))) / HZ;
+ }
+ printk(KERN_DEBUG "FPU Affinity set after %ld emulations\n",
+ mt_fpemul_threshold);
+
+ return 0;
+}
+arch_initcall(mt_fp_affinity_init);
Code Review / kvmfornfv.git / blobdiff