From: Frederic Weisbecker <frederic@kernel.org>
To: Alex Belits <abelits@marvell.com>
Cc: "rostedt@goodmis.org" <rostedt@goodmis.org>,
"mingo@kernel.org" <mingo@kernel.org>,
"peterz@infradead.org" <peterz@infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Prasun Kapoor <pkapoor@marvell.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"linux-api@vger.kernel.org" <linux-api@vger.kernel.org>,
"linux-mm@vger.kernel.org" <linux-mm@vger.kernel.org>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>
Subject: Re: [PATCH 08/12] task_isolation: don't interrupt CPUs with tick_nohz_full_kick_cpu()
Date: Fri, 6 Mar 2020 17:03:42 +0100 [thread overview]
Message-ID: <20200306160341.GE8590@lenoir> (raw)
In-Reply-To: <d7ce01e57d4a35b126e1cb96a63109eaa9781cb6.camel@marvell.com>
On Wed, Mar 04, 2020 at 04:12:40PM +0000, Alex Belits wrote:
> From: Yuri Norov <ynorov@marvell.com>
>
> For nohz_full CPUs the desirable behavior is to receive interrupts
> generated by tick_nohz_full_kick_cpu(). But for hard isolation it's
> obviously not desirable because it breaks isolation.
>
> This patch adds check for it.
>
> Signed-off-by: Alex Belits <abelits@marvell.com>
> ---
> kernel/time/tick-sched.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
> index 1d4dec9d3ee7..fe4503ba1316 100644
> --- a/kernel/time/tick-sched.c
> +++ b/kernel/time/tick-sched.c
> @@ -20,6 +20,7 @@
> #include <linux/sched/clock.h>
> #include <linux/sched/stat.h>
> #include <linux/sched/nohz.h>
> +#include <linux/isolation.h>
> #include <linux/module.h>
> #include <linux/irq_work.h>
> #include <linux/posix-timers.h>
> @@ -262,7 +263,7 @@ static void tick_nohz_full_kick(void)
> */
> void tick_nohz_full_kick_cpu(int cpu)
> {
> - if (!tick_nohz_full_cpu(cpu))
> + if (!tick_nohz_full_cpu(cpu) || task_isolation_on_cpu(cpu))
> return;
I fear you can't do that. A nohz full CPU is kicked for a reason.
As for the other cases, you need to fix the callers.
In the general case, randomly ignoring an interrupt is a correctness
issue.
Thanks.
next prev parent reply other threads:[~2020-03-06 16:03 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-04 16:01 [PATCH 00/12] "Task_isolation" mode Alex Belits
2020-03-04 16:03 ` [PATCH 01/12] task_isolation: vmstat: add quiet_vmstat_sync function Alex Belits
2020-03-04 16:04 ` [PATCH 02/12] task_isolation: vmstat: add vmstat_idle function Alex Belits
2020-03-04 16:07 ` [PATCH 03/12] task_isolation: userspace hard isolation from kernel Alex Belits
2020-03-05 18:33 ` Frederic Weisbecker
2020-03-08 5:32 ` [EXT] " Alex Belits
2020-04-28 14:12 ` Marcelo Tosatti
2020-03-06 15:26 ` Frederic Weisbecker
2020-03-08 6:06 ` [EXT] " Alex Belits
2020-03-06 16:00 ` Frederic Weisbecker
2020-03-08 7:16 ` [EXT] " Alex Belits
2020-03-04 16:08 ` [PATCH 04/12] task_isolation: Add task isolation hooks to arch-independent code Alex Belits
2020-03-04 16:09 ` [PATCH 05/12] task_isolation: arch/x86: enable task isolation functionality Alex Belits
2020-03-04 16:10 ` [PATCH 06/12] task_isolation: arch/arm64: " Alex Belits
2020-03-04 16:31 ` Mark Rutland
2020-03-08 4:48 ` [EXT] " Alex Belits
2020-03-04 16:11 ` [PATCH 07/12] task_isolation: arch/arm: " Alex Belits
2020-03-04 16:12 ` [PATCH 08/12] task_isolation: don't interrupt CPUs with tick_nohz_full_kick_cpu() Alex Belits
2020-03-06 16:03 ` Frederic Weisbecker [this message]
2020-03-08 7:28 ` [EXT] " Alex Belits
2020-03-09 2:38 ` Frederic Weisbecker
2020-03-04 16:13 ` [PATCH 09/12] task_isolation: net: don't flush backlog on CPUs running isolated tasks Alex Belits
2020-03-04 16:14 ` [PATCH 10/12] task_isolation: ringbuffer: don't interrupt CPUs running isolated tasks on buffer resize Alex Belits
2020-03-04 16:15 ` [PATCH 11/12] task_isolation: kick_all_cpus_sync: don't kick isolated cpus Alex Belits
2020-03-06 15:34 ` Frederic Weisbecker
2020-03-08 6:48 ` [EXT] " Alex Belits
2020-03-09 2:28 ` Frederic Weisbecker
2020-03-04 16:16 ` [PATCH 12/12] task_isolation: CONFIG_TASK_ISOLATION prevents distribution of jobs to non-housekeeping CPUs Alex Belits
2020-03-08 3:42 ` [PATCH v2 00/12] "Task_isolation" mode Alex Belits
2020-03-08 3:44 ` [PATCH v2 01/12] task_isolation: vmstat: add quiet_vmstat_sync function Alex Belits
2020-03-08 3:46 ` [PATCH v2 02/12] task_isolation: vmstat: add vmstat_idle function Alex Belits
2020-03-08 3:47 ` [PATCH v2 03/12] task_isolation: userspace hard isolation from kernel Alex Belits
[not found] ` <20200307214254.7a8f6c22@hermes.lan>
2020-03-08 7:33 ` [EXT] " Alex Belits
2020-03-27 8:42 ` Marta Rybczynska
2020-04-06 4:31 ` Kevyn-Alexandre Paré
2020-04-06 4:43 ` Kevyn-Alexandre Paré
2020-03-08 3:48 ` [PATCH v2 04/12] task_isolation: Add task isolation hooks to arch-independent code Alex Belits
2020-03-08 3:49 ` [PATCH v2 05/12] task_isolation: arch/x86: enable task isolation functionality Alex Belits
2020-03-08 3:50 ` [PATCH v2 06/12] task_isolation: arch/arm64: " Alex Belits
2020-03-09 16:59 ` Mark Rutland
2020-03-08 3:52 ` [PATCH v2 07/12] task_isolation: arch/arm: " Alex Belits
2020-03-08 3:53 ` [PATCH v2 08/12] task_isolation: don't interrupt CPUs with tick_nohz_full_kick_cpu() Alex Belits
2020-03-08 3:54 ` [PATCH v2 09/12] task_isolation: net: don't flush backlog on CPUs running isolated tasks Alex Belits
2020-03-08 3:55 ` [PATCH v2 10/12] task_isolation: ringbuffer: don't interrupt CPUs running isolated tasks on buffer resize Alex Belits
2020-04-06 4:27 ` Kevyn-Alexandre Paré
2020-03-08 3:56 ` [PATCH v2 11/12] task_isolation: kick_all_cpus_sync: don't kick isolated cpus Alex Belits
2020-03-08 3:57 ` [PATCH v2 12/12] task_isolation: CONFIG_TASK_ISOLATION prevents distribution of jobs to non-housekeeping CPUs Alex Belits
2020-04-09 15:09 ` [PATCH v3 00/13] "Task_isolation" mode Alex Belits
2020-04-09 15:15 ` [PATCH 01/13] task_isolation: vmstat: add quiet_vmstat_sync function Alex Belits
2020-04-09 15:16 ` [PATCH 02/13] task_isolation: vmstat: add vmstat_idle function Alex Belits
2020-04-09 15:17 ` [PATCH v3 03/13] task_isolation: add instruction synchronization memory barrier Alex Belits
2020-04-15 12:44 ` Mark Rutland
2020-04-19 5:02 ` [EXT] " Alex Belits
2020-04-20 12:23 ` Will Deacon
2020-04-20 12:36 ` Mark Rutland
2020-04-20 13:55 ` Will Deacon
2020-04-21 7:41 ` Will Deacon
2020-04-20 12:45 ` Mark Rutland
2020-04-09 15:20 ` [PATCH v3 04/13] task_isolation: userspace hard isolation from kernel Alex Belits
2020-04-09 18:00 ` Andy Lutomirski
2020-04-19 5:07 ` Alex Belits
2020-04-09 15:21 ` [PATCH 05/13] task_isolation: Add task isolation hooks to arch-independent code Alex Belits
2020-04-09 15:22 ` [PATCH 06/13] task_isolation: arch/x86: enable task isolation functionality Alex Belits
2020-04-09 15:23 ` [PATCH v3 07/13] task_isolation: arch/arm64: " Alex Belits
2020-04-22 12:08 ` Catalin Marinas
2020-04-09 15:24 ` [PATCH v3 08/13] task_isolation: arch/arm: " Alex Belits
2020-04-09 15:25 ` [PATCH v3 09/13] task_isolation: don't interrupt CPUs with tick_nohz_full_kick_cpu() Alex Belits
2020-04-09 15:26 ` [PATCH v3 10/13] task_isolation: net: don't flush backlog on CPUs running isolated tasks Alex Belits
2020-04-09 15:27 ` [PATCH v3 11/13] task_isolation: ringbuffer: don't interrupt CPUs running isolated tasks on buffer resize Alex Belits
2020-04-09 15:27 ` [PATCH v3 12/13] task_isolation: kick_all_cpus_sync: don't kick isolated cpus Alex Belits
2020-04-09 15:28 ` [PATCH v3 13/13] task_isolation: CONFIG_TASK_ISOLATION prevents distribution of jobs to non-housekeeping CPUs Alex Belits
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