diff mbox series

[v4,2/4] sched/isolation: Extend nohz_full to isolate managed IRQs

Message ID 20200928183529.471328-3-nitesh@redhat.com
State New
Headers show
Series isolation: limit msix vectors to housekeeping CPUs | expand

Commit Message

Nitesh Narayan Lal Sept. 28, 2020, 6:35 p.m. UTC
Extend nohz_full feature set to include isolation from managed IRQS. This
is required specifically for setups that only uses nohz_full and still
requires isolation for maintaining lower latency for the listed CPUs.

Suggested-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com>
---
 kernel/sched/isolation.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Peter Zijlstra Oct. 23, 2020, 1:25 p.m. UTC | #1
On Mon, Sep 28, 2020 at 02:35:27PM -0400, Nitesh Narayan Lal wrote:
> Extend nohz_full feature set to include isolation from managed IRQS. This


So you say it's for managed-irqs, the feature is actually called
MANAGED_IRQ, but, AFAICT, it does *NOT* in fact affect managed IRQs.

Also, as per Thomas' earlier points, managed-irqs are in fact perfectly
fine and don't need help at at...

> is required specifically for setups that only uses nohz_full and still

> requires isolation for maintaining lower latency for the listed CPUs.

> 

> Suggested-by: Frederic Weisbecker <frederic@kernel.org>

> Signed-off-by: Nitesh Narayan Lal <nitesh@redhat.com>

> ---

>  kernel/sched/isolation.c | 2 +-

>  1 file changed, 1 insertion(+), 1 deletion(-)

> 

> diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c

> index 5a6ea03f9882..9df9598a9e39 100644

> --- a/kernel/sched/isolation.c

> +++ b/kernel/sched/isolation.c

> @@ -141,7 +141,7 @@ static int __init housekeeping_nohz_full_setup(char *str)

>  	unsigned int flags;

>  

>  	flags = HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU |

> -		HK_FLAG_MISC | HK_FLAG_KTHREAD;

> +		HK_FLAG_MISC | HK_FLAG_KTHREAD | HK_FLAG_MANAGED_IRQ;

>  

>  	return housekeeping_setup(str, flags);

>  }

> -- 

> 2.18.2

>
diff mbox series

Patch

diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
index 5a6ea03f9882..9df9598a9e39 100644
--- a/kernel/sched/isolation.c
+++ b/kernel/sched/isolation.c
@@ -141,7 +141,7 @@  static int __init housekeeping_nohz_full_setup(char *str)
 	unsigned int flags;
 
 	flags = HK_FLAG_TICK | HK_FLAG_WQ | HK_FLAG_TIMER | HK_FLAG_RCU |
-		HK_FLAG_MISC | HK_FLAG_KTHREAD;
+		HK_FLAG_MISC | HK_FLAG_KTHREAD | HK_FLAG_MANAGED_IRQ;
 
 	return housekeeping_setup(str, flags);
 }