Re: [PATCH 3/7] RT: Only consider online CPUs when pushing rt tasks

From: Steven Rostedt
Date: Fri Oct 12 2007 - 08:11:24 EST



--

On Thu, 11 Oct 2007, Gregory Haskins wrote:

> task->cpus_allowed can have bit positions that are set for CPUs that are
> not currently online. So we optimze our search by ANDing against the online
> set.
>
> Signed-off-by: Gregory Haskins <ghaskins@xxxxxxxxxx>
> ---
>
> kernel/sched.c | 6 +++++-
> 1 files changed, 5 insertions(+), 1 deletions(-)
>
> diff --git a/kernel/sched.c b/kernel/sched.c
> index 24b38b4..0ca3905 100644
> --- a/kernel/sched.c
> +++ b/kernel/sched.c
> @@ -1510,10 +1510,14 @@ static int push_rt_task(struct rq *this_rq)
>
> /* Only try this algorithm three times */
> for (tries = 0; tries < 3; tries++) {
> + cpumask_t mask;
> +
> + cpus_and(mask, cpu_online_map, next_task->cpus_allowed);
> +

Gag! I definitely sent you an old patch. I fixed this a while ago :-(

-- Steve

> /*
> * Scan each rq for the lowest prio.
> */
> - for_each_cpu_mask(cpu, next_task->cpus_allowed) {
> + for_each_cpu_mask(cpu, mask) {
> struct rq *rq = &per_cpu(runqueues, cpu);
>
> if (cpu == smp_processor_id())
>
> -
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>
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