diff options
Diffstat (limited to 'kernel/sched_cpupri.c')
| -rw-r--r-- | kernel/sched_cpupri.c | 204 |
1 files changed, 0 insertions, 204 deletions
diff --git a/kernel/sched_cpupri.c b/kernel/sched_cpupri.c deleted file mode 100644 index 2722dc1b413..00000000000 --- a/kernel/sched_cpupri.c +++ /dev/null @@ -1,204 +0,0 @@ -/* - * kernel/sched_cpupri.c - * - * CPU priority management - * - * Copyright (C) 2007-2008 Novell - * - * Author: Gregory Haskins <ghaskins@novell.com> - * - * This code tracks the priority of each CPU so that global migration - * decisions are easy to calculate. Each CPU can be in a state as follows: - * - * (INVALID), IDLE, NORMAL, RT1, ... RT99 - * - * going from the lowest priority to the highest. CPUs in the INVALID state - * are not eligible for routing. The system maintains this state with - * a 2 dimensional bitmap (the first for priority class, the second for cpus - * in that class). Therefore a typical application without affinity - * restrictions can find a suitable CPU with O(1) complexity (e.g. two bit - * searches). For tasks with affinity restrictions, the algorithm has a - * worst case complexity of O(min(102, nr_domcpus)), though the scenario that - * yields the worst case search is fairly contrived. - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License - * as published by the Free Software Foundation; version 2 - * of the License. - */ - -#include <linux/gfp.h> -#include "sched_cpupri.h" - -/* Convert between a 140 based task->prio, and our 102 based cpupri */ -static int convert_prio(int prio) -{ - int cpupri; - - if (prio == CPUPRI_INVALID) - cpupri = CPUPRI_INVALID; - else if (prio == MAX_PRIO) - cpupri = CPUPRI_IDLE; - else if (prio >= MAX_RT_PRIO) - cpupri = CPUPRI_NORMAL; - else - cpupri = MAX_RT_PRIO - prio + 1; - - return cpupri; -} - -#define for_each_cpupri_active(array, idx) \ - for_each_set_bit(idx, array, CPUPRI_NR_PRIORITIES) - -/** - * cpupri_find - find the best (lowest-pri) CPU in the system - * @cp: The cpupri context - * @p: The task - * @lowest_mask: A mask to fill in with selected CPUs (or NULL) - * - * Note: This function returns the recommended CPUs as calculated during the - * current invocation. By the time the call returns, the CPUs may have in - * fact changed priorities any number of times. While not ideal, it is not - * an issue of correctness since the normal rebalancer logic will correct - * any discrepancies created by racing against the uncertainty of the current - * priority configuration. - * - * Returns: (int)bool - CPUs were found - */ -int cpupri_find(struct cpupri *cp, struct task_struct *p, - struct cpumask *lowest_mask) -{ - int idx = 0; - int task_pri = convert_prio(p->prio); - - for_each_cpupri_active(cp->pri_active, idx) { - struct cpupri_vec *vec = &cp->pri_to_cpu[idx]; - - if (idx >= task_pri) - break; - - if (cpumask_any_and(&p->cpus_allowed, vec->mask) >= nr_cpu_ids) - continue; - - if (lowest_mask) { - cpumask_and(lowest_mask, &p->cpus_allowed, vec->mask); - - /* - * We have to ensure that we have at least one bit - * still set in the array, since the map could have - * been concurrently emptied between the first and - * second reads of vec->mask. If we hit this - * condition, simply act as though we never hit this - * priority level and continue on. - */ - if (cpumask_any(lowest_mask) >= nr_cpu_ids) - continue; - } - - return 1; - } - - return 0; -} - -/** - * cpupri_set - update the cpu priority setting - * @cp: The cpupri context - * @cpu: The target cpu - * @pri: The priority (INVALID-RT99) to assign to this CPU - * - * Note: Assumes cpu_rq(cpu)->lock is locked - * - * Returns: (void) - */ -void cpupri_set(struct cpupri *cp, int cpu, int newpri) -{ - int *currpri = &cp->cpu_to_pri[cpu]; - int oldpri = *currpri; - unsigned long flags; - - newpri = convert_prio(newpri); - - BUG_ON(newpri >= CPUPRI_NR_PRIORITIES); - - if (newpri == oldpri) - return; - - /* - * If the cpu was currently mapped to a different value, we - * need to map it to the new value then remove the old value. - * Note, we must add the new value first, otherwise we risk the - * cpu being cleared from pri_active, and this cpu could be - * missed for a push or pull. - */ - if (likely(newpri != CPUPRI_INVALID)) { - struct cpupri_vec *vec = &cp->pri_to_cpu[newpri]; - - raw_spin_lock_irqsave(&vec->lock, flags); - - cpumask_set_cpu(cpu, vec->mask); - vec->count++; - if (vec->count == 1) - set_bit(newpri, cp->pri_active); - - raw_spin_unlock_irqrestore(&vec->lock, flags); - } - if (likely(oldpri != CPUPRI_INVALID)) { - struct cpupri_vec *vec = &cp->pri_to_cpu[oldpri]; - - raw_spin_lock_irqsave(&vec->lock, flags); - - vec->count--; - if (!vec->count) - clear_bit(oldpri, cp->pri_active); - cpumask_clear_cpu(cpu, vec->mask); - - raw_spin_unlock_irqrestore(&vec->lock, flags); - } - - *currpri = newpri; -} - -/** - * cpupri_init - initialize the cpupri structure - * @cp: The cpupri context - * @bootmem: true if allocations need to use bootmem - * - * Returns: -ENOMEM if memory fails. - */ -int cpupri_init(struct cpupri *cp) -{ - int i; - - memset(cp, 0, sizeof(*cp)); - - for (i = 0; i < CPUPRI_NR_PRIORITIES; i++) { - struct cpupri_vec *vec = &cp->pri_to_cpu[i]; - - raw_spin_lock_init(&vec->lock); - vec->count = 0; - if (!zalloc_cpumask_var(&vec->mask, GFP_KERNEL)) - goto cleanup; - } - - for_each_possible_cpu(i) - cp->cpu_to_pri[i] = CPUPRI_INVALID; - return 0; - -cleanup: - for (i--; i >= 0; i--) - free_cpumask_var(cp->pri_to_cpu[i].mask); - return -ENOMEM; -} - -/** - * cpupri_cleanup - clean up the cpupri structure - * @cp: The cpupri context - */ -void cpupri_cleanup(struct cpupri *cp) -{ - int i; - - for (i = 0; i < CPUPRI_NR_PRIORITIES; i++) - free_cpumask_var(cp->pri_to_cpu[i].mask); -} |