diff options
| -rw-r--r-- | kernel/sched_rt.c | 49 |
1 files changed, 36 insertions, 13 deletions
diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 52d88f1..61d1988 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -296,29 +296,36 @@ static struct task_struct *pick_next_highest_task_rt(struct rq *rq, } static DEFINE_PER_CPU(cpumask_t, local_cpu_mask); -static DEFINE_PER_CPU(cpumask_t, valid_cpu_mask); static int find_lowest_cpus(struct task_struct *task, cpumask_t *lowest_mask) { - int cpu; - cpumask_t *valid_mask = &__get_cpu_var(valid_cpu_mask); int lowest_prio = -1; + int lowest_cpu = -1; int count = 0; + int cpu; - cpus_clear(*lowest_mask); - cpus_and(*valid_mask, cpu_online_map, task->cpus_allowed); + cpus_and(*lowest_mask, cpu_online_map, task->cpus_allowed); /* * Scan each rq for the lowest prio. */ - for_each_cpu_mask(cpu, *valid_mask) { + for_each_cpu_mask(cpu, *lowest_mask) { struct rq *rq = cpu_rq(cpu); /* We look for lowest RT prio or non-rt CPU */ if (rq->rt.highest_prio >= MAX_RT_PRIO) { - if (count) + /* + * if we already found a low RT queue + * and now we found this non-rt queue + * clear the mask and set our bit. + * Otherwise just return the queue as is + * and the count==1 will cause the algorithm + * to use the first bit found. + */ + if (lowest_cpu != -1) { cpus_clear(*lowest_mask); - cpu_set(rq->cpu, *lowest_mask); + cpu_set(rq->cpu, *lowest_mask); + } return 1; } @@ -328,13 +335,29 @@ static int find_lowest_cpus(struct task_struct *task, cpumask_t *lowest_mask) if (rq->rt.highest_prio > lowest_prio) { /* new low - clear old data */ lowest_prio = rq->rt.highest_prio; - if (count) { - cpus_clear(*lowest_mask); - count = 0; - } + lowest_cpu = cpu; + count = 0; } - cpu_set(rq->cpu, *lowest_mask); count++; + } else + cpu_clear(cpu, *lowest_mask); + } + + /* + * Clear out all the set bits that represent + * runqueues that were of higher prio than + * the lowest_prio. + */ + if (lowest_cpu > 0) { + /* + * Perhaps we could add another cpumask op to + * zero out bits. Like cpu_zero_bits(cpumask, nrbits); + * Then that could be optimized to use memset and such. + */ + for_each_cpu_mask(cpu, *lowest_mask) { + if (cpu >= lowest_cpu) + break; + cpu_clear(cpu, *lowest_mask); } } |
