Messages in this thread Patch in this message | | | Subject | [patch] sched/autogroup: Fix 64bit kernel nice adjustment | From | Mike Galbraith <> | Date | Wed, 23 Nov 2016 11:33:37 +0100 |
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On Tue, 2016-11-22 at 16:59 +0100, Michael Kerrisk (man-pages) wrote:
> ┌─────────────────────────────────────────────────────┐ > │FIXME │ > ├─────────────────────────────────────────────────────┤ > │Regarding the previous paragraph... My tests indi‐ │ > │cate that writing *any* value to the autogroup file │ > │causes the task group to get a lower priority. This │
Because autogroup didn't call the then meaningless scale_load()...
Autogroup nice level adjustment has been broken ever since load resolution was increased for 64bit kernels. Use scale_load() to scale group weight.
Signed-off-by: Mike Galbraith <umgwanakikbuti@gmail.com> Reported-by: Michael Kerrisk <mtk.manpages@gmail.com> Cc: stable@vger.kernel.org --- kernel/sched/auto_group.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/kernel/sched/auto_group.c +++ b/kernel/sched/auto_group.c @@ -192,6 +192,7 @@ int proc_sched_autogroup_set_nice(struct { static unsigned long next = INITIAL_JIFFIES; struct autogroup *ag; + unsigned long shares; int err; if (nice < MIN_NICE || nice > MAX_NICE) @@ -210,9 +211,10 @@ int proc_sched_autogroup_set_nice(struct next = HZ / 10 + jiffies; ag = autogroup_task_get(p); + shares = scale_load(sched_prio_to_weight[nice + 20]); down_write(&ag->lock); - err = sched_group_set_shares(ag->tg, sched_prio_to_weight[nice + 20]); + err = sched_group_set_shares(ag->tg, shares); if (!err) ag->nice = nice; up_write(&ag->lock);
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