lkml.org 
[lkml]   [2015]   [Mar]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: [PATCH RESEND 1/2] sched/deadline: Fix wrong cpudl_find() in check_preempt_equal_dl()
    From
    Ping Juri

    > From: Xunlei Pang <pang.xunlei@linaro.org>
    >
    > In check_preempt_equal_dl(), cpudl_find() is called with a NULL
    > later_mask, thus cpudl_find() here doesn't check cpudl::free_cpus
    > at all.
    >
    > This patch takles this issue by always passing a non-NULL later_mask
    > to cpudl_find(), thereby fixing this issue.
    >
    > Signed-off-by: Xunlei Pang <pang.xunlei@linaro.org>
    > ---
    > kernel/sched/cpudeadline.c | 8 +++-----
    > kernel/sched/deadline.c | 15 +++++++++++----
    > 2 files changed, 14 insertions(+), 9 deletions(-)
    >
    > diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
    > index c6acb07..f331fcf 100644
    > --- a/kernel/sched/cpudeadline.c
    > +++ b/kernel/sched/cpudeadline.c
    > @@ -97,7 +97,7 @@ static inline int cpudl_maximum(struct cpudl *cp)
    > * cpudl_find - find the best (later-dl) CPU in the system
    > * @cp: the cpudl max-heap context
    > * @p: the task
    > - * @later_mask: a mask to fill in with the selected CPUs (or NULL)
    > + * @later_mask: a mask to fill in with the selected CPUs (not NULL)
    > *
    > * Returns: int - best CPU (heap maximum if suitable)
    > */
    > @@ -107,15 +107,13 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
    > int best_cpu = -1;
    > const struct sched_dl_entity *dl_se = &p->dl;
    >
    > - if (later_mask &&
    > - cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) {
    > + if (cpumask_and(later_mask, cp->free_cpus, &p->cpus_allowed)) {
    > best_cpu = cpumask_any(later_mask);
    > goto out;
    > } else if (cpumask_test_cpu(cpudl_maximum(cp), &p->cpus_allowed) &&
    > dl_time_before(dl_se->deadline, cp->elements[0].dl)) {
    > best_cpu = cpudl_maximum(cp);
    > - if (later_mask)
    > - cpumask_set_cpu(best_cpu, later_mask);
    > + cpumask_set_cpu(best_cpu, later_mask);
    > }
    >
    > out:
    > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
    > index 0a81a95..256099c 100644
    > --- a/kernel/sched/deadline.c
    > +++ b/kernel/sched/deadline.c
    > @@ -964,14 +964,23 @@ out:
    > return cpu;
    > }
    >
    > +static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask_dl);
    > +
    > static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p)
    > {
    > + struct cpumask *later_mask =
    > + this_cpu_cpumask_var_ptr(local_cpu_mask_dl);
    > +
    > + /* Make sure the mask is initialized first */
    > + if (unlikely(!later_mask))
    > + return;
    > +
    > /*
    > * Current can't be migrated, useless to reschedule,
    > * let's hope p can move out.
    > */
    > if (rq->curr->nr_cpus_allowed == 1 ||
    > - cpudl_find(&rq->rd->cpudl, rq->curr, NULL) == -1)
    > + cpudl_find(&rq->rd->cpudl, rq->curr, later_mask) == -1)
    > return;
    >
    > /*
    > @@ -979,7 +988,7 @@ static void check_preempt_equal_dl(struct rq *rq, struct task_struct *p)
    > * see if it is pushed or pulled somewhere else.
    > */
    > if (p->nr_cpus_allowed != 1 &&
    > - cpudl_find(&rq->rd->cpudl, p, NULL) != -1)
    > + cpudl_find(&rq->rd->cpudl, p, later_mask) != -1)
    > return;
    >
    > resched_curr(rq);
    > @@ -1173,8 +1182,6 @@ next_node:
    > return NULL;
    > }
    >
    > -static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask_dl);
    > -
    > static int find_later_rq(struct task_struct *task)
    > {
    > struct sched_domain *sd;
    > --
    > 1.9.1
    >
    >


    \
     
     \ /
      Last update: 2015-03-27 16:01    [W:3.963 / U:0.940 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site