| Date | Thu, 1 Aug 2013 16:38:57 +0100 | From | Mel Gorman <> | Subject | Re: [PATCH 08/18] sched: Reschedule task on preferred NUMA node once selected |
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On Thu, Aug 01, 2013 at 10:17:57AM +0530, Srikar Dronamraju wrote: > * Mel Gorman <mgorman@suse.de> [2013-07-15 16:20:10]: > > > A preferred node is selected based on the node the most NUMA hinting > > faults was incurred on. There is no guarantee that the task is running > > on that node at the time so this patch rescheules the task to run on > > the most idle CPU of the selected node when selected. This avoids > > waiting for the balancer to make a decision. > > > > Signed-off-by: Mel Gorman <mgorman@suse.de> > > --- > > kernel/sched/core.c | 17 +++++++++++++++++ > > kernel/sched/fair.c | 46 +++++++++++++++++++++++++++++++++++++++++++++- > > kernel/sched/sched.h | 1 + > > 3 files changed, 63 insertions(+), 1 deletion(-) > > > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > > index 5e02507..b67a102 100644 > > --- a/kernel/sched/core.c > > +++ b/kernel/sched/core.c > > @@ -4856,6 +4856,23 @@ fail: > > return ret; > > } > > > > +#ifdef CONFIG_NUMA_BALANCING > > +/* Migrate current task p to target_cpu */ > > +int migrate_task_to(struct task_struct *p, int target_cpu) > > +{ > > + struct migration_arg arg = { p, target_cpu }; > > + int curr_cpu = task_cpu(p); > > + > > + if (curr_cpu == target_cpu) > > + return 0; > > + > > + if (!cpumask_test_cpu(target_cpu, tsk_cpus_allowed(p))) > > + return -EINVAL; > > + > > + return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg); > > As I had noted earlier, this upsets schedstats badly. > Can we add a TODO for this patch, which mentions that schedstats need to > taken care. >
I added a TODO comment because there is a possibility that this will all change again with the stop_two_cpus patch.
-- Mel Gorman SUSE Labs
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