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 11/12] task_isolation: kick_all_cpus_sync: don't kick isolated cpus
Date: Fri, 6 Mar 2020 16:34:47 +0100 [thread overview]
Message-ID: <20200306153446.GC8590@lenoir> (raw)
In-Reply-To: <dfa5e0e9f34e6ff0ef048c81bc70496354f31300.camel@marvell.com>
On Wed, Mar 04, 2020 at 04:15:24PM +0000, Alex Belits wrote:
> From: Yuri Norov <ynorov@marvell.com>
>
> Make sure that kick_all_cpus_sync() does not call CPUs that are running
> isolated tasks.
>
> Signed-off-by: Alex Belits <abelits@marvell.com>
> ---
> kernel/smp.c | 14 +++++++++++++-
> 1 file changed, 13 insertions(+), 1 deletion(-)
>
> diff --git a/kernel/smp.c b/kernel/smp.c
> index 3a8bcbdd4ce6..d9b4b2fedfed 100644
> --- a/kernel/smp.c
> +++ b/kernel/smp.c
> @@ -731,9 +731,21 @@ static void do_nothing(void *unused)
> */
> void kick_all_cpus_sync(void)
> {
> + struct cpumask mask;
> +
> /* Make sure the change is visible before we kick the cpus */
> smp_mb();
> - smp_call_function(do_nothing, NULL, 1);
> +
> + preempt_disable();
> +#ifdef CONFIG_TASK_ISOLATION
> + cpumask_clear(&mask);
> + task_isolation_cpumask(&mask);
> + cpumask_complement(&mask, &mask);
> +#else
> + cpumask_setall(&mask);
> +#endif
> + smp_call_function_many(&mask, do_nothing, NULL, 1);
> + preempt_enable();
> }
That looks very dangerous, the callers of kick_all_cpus_sync() want to
sync all CPUs for a reason. You will rather need to fix the callers.
Thanks.
> EXPORT_SYMBOL_GPL(kick_all_cpus_sync);
>
> --
> 2.20.1
>
next prev parent reply other threads:[~2020-03-06 15:34 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
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 [this message]
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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