From: Frederic Weisbecker <frederic@kernel.org>
To: Alex Belits <abelits@marvell.com>
Cc: "rostedt@goodmis.org" <rostedt@goodmis.org>,
Prasun Kapoor <pkapoor@marvell.com>,
"mingo@kernel.org" <mingo@kernel.org>,
"davem@davemloft.net" <davem@davemloft.net>,
"linux-api@vger.kernel.org" <linux-api@vger.kernel.org>,
"peterz@infradead.org" <peterz@infradead.org>,
"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
"catalin.marinas@arm.com" <catalin.marinas@arm.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"will@kernel.org" <will@kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Subject: Re: [PATCH v4 11/13] task_isolation: net: don't flush backlog on CPUs running isolated tasks
Date: Thu, 1 Oct 2020 16:47:31 +0200 [thread overview]
Message-ID: <20201001144731.GC6595@lothringen> (raw)
In-Reply-To: <01470cf1f1a2e79e46a87bb5a8a4780a1c3cc740.camel@marvell.com>
On Wed, Jul 22, 2020 at 02:58:24PM +0000, Alex Belits wrote:
> From: Yuri Norov <ynorov@marvell.com>
>
> If CPU runs isolated task, there's no any backlog on it, and
> so we don't need to flush it.
What guarantees that we have no backlog on it?
> Currently flush_all_backlogs()
> enqueues corresponding work on all CPUs including ones that run
> isolated tasks. It leads to breaking task isolation for nothing.
>
> In this patch, backlog flushing is enqueued only on non-isolated CPUs.
>
> Signed-off-by: Yuri Norov <ynorov@marvell.com>
> [abelits@marvell.com: use safe task_isolation_on_cpu() implementation]
> Signed-off-by: Alex Belits <abelits@marvell.com>
> ---
> net/core/dev.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/net/core/dev.c b/net/core/dev.c
> index 90b59fc50dc9..83a282f7453d 100644
> --- a/net/core/dev.c
> +++ b/net/core/dev.c
> @@ -74,6 +74,7 @@
> #include <linux/cpu.h>
> #include <linux/types.h>
> #include <linux/kernel.h>
> +#include <linux/isolation.h>
> #include <linux/hash.h>
> #include <linux/slab.h>
> #include <linux/sched.h>
> @@ -5624,9 +5625,13 @@ static void flush_all_backlogs(void)
>
> get_online_cpus();
>
> - for_each_online_cpu(cpu)
> + smp_rmb();
What is it ordering?
> + for_each_online_cpu(cpu) {
> + if (task_isolation_on_cpu(cpu))
> + continue;
> queue_work_on(cpu, system_highpri_wq,
> per_cpu_ptr(&flush_works, cpu));
> + }
>
> for_each_online_cpu(cpu)
> flush_work(per_cpu_ptr(&flush_works, cpu));
Thanks.
next prev parent reply other threads:[~2020-10-01 14:47 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-22 14:44 [PATCH v4 00/13] "Task_isolation" mode Alex Belits
2020-07-22 14:47 ` [PATCH v4 01/13] task_isolation: vmstat: add quiet_vmstat_sync function Alex Belits
2020-07-22 14:48 ` [PATCH v4 02/13] task_isolation: vmstat: add vmstat_idle function Alex Belits
2020-07-22 14:49 ` [PATCH v4 03/13] task_isolation: userspace hard isolation from kernel Alex Belits
2020-10-01 13:56 ` Frederic Weisbecker
2020-10-04 14:44 ` [EXT] " Alex Belits
2020-10-04 23:14 ` Frederic Weisbecker
2020-10-05 18:52 ` Nitesh Narayan Lal
2020-10-06 10:35 ` Frederic Weisbecker
2020-10-17 1:13 ` Alex Belits
2020-10-17 1:08 ` Alex Belits
2020-10-17 16:08 ` Thomas Gleixner
2020-10-17 16:15 ` Alex Belits
2020-10-17 20:03 ` Thomas Gleixner
2020-10-06 11:01 ` Alex Belits
2020-10-01 14:40 ` Frederic Weisbecker
2020-10-04 15:01 ` [EXT] " Alex Belits
2020-07-22 14:51 ` [PATCH v4 04/13] task_isolation: Add task isolation hooks to arch-independent code Alex Belits
2020-07-22 14:51 ` [PATCH v4 05/13] task_isolation: Add xen-specific hook Alex Belits
2020-07-22 14:53 ` [PATCH 06/13] task_isolation: Add driver-specific hooks Alex Belits
2020-07-22 14:54 ` [PATCH v4 07/13] task_isolation: arch/x86: enable task isolation functionality Alex Belits
2020-07-22 14:55 ` [PATCH 08/13] task_isolation: arch/arm64: " Alex Belits
2020-07-22 14:56 ` [PATCH v4 09/13] task_isolation: arch/arm: " Alex Belits
2020-07-22 14:57 ` [PATCH v4 10/13] task_isolation: don't interrupt CPUs with tick_nohz_full_kick_cpu() Alex Belits
2020-10-01 14:44 ` Frederic Weisbecker
2020-10-04 15:22 ` [EXT] " Alex Belits
2020-10-06 21:41 ` Frederic Weisbecker
2020-10-17 0:17 ` Alex Belits
2020-07-22 14:58 ` [PATCH v4 11/13] task_isolation: net: don't flush backlog on CPUs running isolated tasks Alex Belits
2020-10-01 14:47 ` Frederic Weisbecker [this message]
2020-10-04 17:12 ` [EXT] " Alex Belits
2021-01-22 14:13 ` Marcelo Tosatti
2021-01-22 16:13 ` Paolo Abeni
2020-07-22 14:59 ` [PATCH v4 12/13] task_isolation: ringbuffer: don't interrupt CPUs running isolated tasks on buffer resize Alex Belits
2020-07-22 14:59 ` [PATCH 13/13] task_isolation: kick_all_cpus_sync: don't kick isolated cpus Alex Belits
2020-07-23 13:17 ` [PATCH v4 00/13] "Task_isolation" mode Thomas Gleixner
2020-07-23 14:26 ` Peter Zijlstra
2020-07-23 14:53 ` Thomas Gleixner
2020-07-23 14:29 ` Peter Zijlstra
2020-07-23 15:41 ` [EXT] " Alex Belits
2020-07-23 15:48 ` Peter Zijlstra
2020-07-23 16:19 ` Alex Belits
2020-07-23 15:18 ` Alex Belits
2020-07-23 15:49 ` Peter Zijlstra
2020-07-23 16:50 ` Alex Belits
2020-07-23 21:44 ` Thomas Gleixner
2020-07-24 3:00 ` [EXT] " Alex Belits
2020-07-24 16:08 ` Thomas Gleixner
2020-07-23 21:31 ` Thomas Gleixner
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