From: Qais Yousef <qais.yousef@arm.com>
To: Will Deacon <will@kernel.org>
Cc: Quentin Perret <qperret@google.com>,
linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org,
linux-kernel@vger.kernel.org,
Catalin Marinas <catalin.marinas@arm.com>,
Marc Zyngier <maz@kernel.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Suren Baghdasaryan <surenb@google.com>, Tejun Heo <tj@kernel.org>,
Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Ingo Molnar <mingo@redhat.com>,
Juri Lelli <juri.lelli@redhat.com>,
Vincent Guittot <vincent.guittot@linaro.org>,
kernel-team@android.com
Subject: Re: [PATCH v4 09/14] cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1
Date: Wed, 2 Dec 2020 11:34:10 +0000 [thread overview]
Message-ID: <20201202113410.dx4m2gb7zkyregys@e107158-lin.cambridge.arm.com> (raw)
In-Reply-To: <20201201223056.GB28496@willie-the-truck>
On 12/01/20 22:30, Will Deacon wrote:
> On Tue, Dec 01, 2020 at 03:56:49PM +0000, Quentin Perret wrote:
> > On Tuesday 01 Dec 2020 at 14:11:21 (+0000), Qais Yousef wrote:
> > > For cpusets, if hotunplug results in an empty cpuset, then all tasks are moved
> > > to the nearest ancestor if I read the code correctly. In our case, only 32bit
> > > tasks have to move out to retain this behavior. Since now for the first time we
> > > have tasks that can't run on all cpus.
> > >
> > > Which by the way might be the right behavior for 64bit tasks execing 32bit
> > > binary in a 64bit only cpuset. I suggested SIGKILL'ing them but maybe moving
> > > them to the nearest ancestor too is more aligned with the behavior above.
> >
> > Hmm, I guess that means putting all 32-bit-execd-from-64-bit tasks in
> > the root group in Android. I'll try and check the implications, but that
> > might be just fine... Sounds like a sensible behaviour to me anyways.
>
> I'll look into this -- anything we can do to avoid forcefully resetting the
> affinity mask to the arch_task_cpu_possible_mask() is worth considering.
Happy to lend a hand, just let me know.
Thanks
--
Qais Yousef
WARNING: multiple messages have this Message-ID (diff)
From: Qais Yousef <qais.yousef@arm.com>
To: Will Deacon <will@kernel.org>
Cc: linux-arch@vger.kernel.org, Juri Lelli <juri.lelli@redhat.com>,
kernel-team@android.com,
Vincent Guittot <vincent.guittot@linaro.org>,
Quentin Perret <qperret@google.com>,
Peter Zijlstra <peterz@infradead.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Johannes Weiner <hannes@cmpxchg.org>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@redhat.com>,
Li Zefan <lizefan@huawei.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Marc Zyngier <maz@kernel.org>, Tejun Heo <tj@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v4 09/14] cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1
Date: Wed, 2 Dec 2020 11:34:10 +0000 [thread overview]
Message-ID: <20201202113410.dx4m2gb7zkyregys@e107158-lin.cambridge.arm.com> (raw)
In-Reply-To: <20201201223056.GB28496@willie-the-truck>
On 12/01/20 22:30, Will Deacon wrote:
> On Tue, Dec 01, 2020 at 03:56:49PM +0000, Quentin Perret wrote:
> > On Tuesday 01 Dec 2020 at 14:11:21 (+0000), Qais Yousef wrote:
> > > For cpusets, if hotunplug results in an empty cpuset, then all tasks are moved
> > > to the nearest ancestor if I read the code correctly. In our case, only 32bit
> > > tasks have to move out to retain this behavior. Since now for the first time we
> > > have tasks that can't run on all cpus.
> > >
> > > Which by the way might be the right behavior for 64bit tasks execing 32bit
> > > binary in a 64bit only cpuset. I suggested SIGKILL'ing them but maybe moving
> > > them to the nearest ancestor too is more aligned with the behavior above.
> >
> > Hmm, I guess that means putting all 32-bit-execd-from-64-bit tasks in
> > the root group in Android. I'll try and check the implications, but that
> > might be just fine... Sounds like a sensible behaviour to me anyways.
>
> I'll look into this -- anything we can do to avoid forcefully resetting the
> affinity mask to the arch_task_cpu_possible_mask() is worth considering.
Happy to lend a hand, just let me know.
Thanks
--
Qais Yousef
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next prev parent reply other threads:[~2020-12-02 11:35 UTC|newest]
Thread overview: 122+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-24 15:50 [PATCH v4 00/14] An alternative series for asymmetric AArch32 systems Will Deacon
2020-11-24 15:50 ` Will Deacon
2020-11-24 15:50 ` [PATCH v4 01/14] arm64: cpuinfo: Split AArch32 registers out into a separate struct Will Deacon
2020-11-24 15:50 ` Will Deacon
2020-11-24 15:50 ` [PATCH v4 02/14] arm64: Allow mismatched 32-bit EL0 support Will Deacon
2020-11-24 15:50 ` Will Deacon
2020-11-27 10:25 ` Marc Zyngier
2020-11-27 10:25 ` Marc Zyngier
2020-11-27 11:50 ` Will Deacon
2020-11-27 11:50 ` Will Deacon
2020-11-27 13:09 ` Qais Yousef
2020-11-27 13:09 ` Qais Yousef
2020-12-01 16:56 ` Will Deacon
2020-12-01 16:56 ` Will Deacon
2020-12-02 13:16 ` Qais Yousef
2020-12-02 13:16 ` Qais Yousef
2020-11-24 15:50 ` [PATCH v4 03/14] KVM: arm64: Kill 32-bit vCPUs on systems with mismatched " Will Deacon
2020-11-24 15:50 ` Will Deacon
2020-11-27 10:26 ` Marc Zyngier
2020-11-27 10:26 ` Marc Zyngier
2020-11-27 11:53 ` Will Deacon
2020-11-27 11:53 ` Will Deacon
2020-11-27 17:14 ` Marc Zyngier
2020-11-27 17:14 ` Marc Zyngier
2020-11-27 17:24 ` Quentin Perret
2020-11-27 17:24 ` Quentin Perret
2020-11-27 18:16 ` Marc Zyngier
2020-11-27 18:16 ` Marc Zyngier
2020-12-01 16:57 ` Will Deacon
2020-12-01 16:57 ` Will Deacon
2020-12-02 8:18 ` Marc Zyngier
2020-12-02 8:18 ` Marc Zyngier
2020-12-02 17:27 ` Will Deacon
2020-12-02 17:27 ` Will Deacon
2020-11-24 15:50 ` [PATCH v4 04/14] arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs Will Deacon
2020-11-24 15:50 ` Will Deacon
2020-11-27 13:12 ` Qais Yousef
2020-11-27 13:12 ` Qais Yousef
2020-12-01 16:56 ` Will Deacon
2020-12-01 16:56 ` Will Deacon
2020-12-02 13:52 ` Qais Yousef
2020-12-02 13:52 ` Qais Yousef
2020-12-02 17:42 ` Will Deacon
2020-12-02 17:42 ` Will Deacon
2020-11-24 15:50 ` [PATCH v4 05/14] arm64: Advertise CPUs capable of running 32-bit applications in sysfs Will Deacon
2020-11-24 15:50 ` Will Deacon
2020-11-24 15:50 ` [PATCH v4 06/14] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 Will Deacon
2020-11-24 15:50 ` Will Deacon
2020-11-27 13:17 ` Qais Yousef
2020-11-27 13:17 ` Qais Yousef
2020-12-01 16:56 ` Will Deacon
2020-12-01 16:56 ` Will Deacon
2020-11-24 15:50 ` [PATCH v4 07/14] sched: Introduce restrict_cpus_allowed_ptr() to limit task CPU affinity Will Deacon
2020-11-24 15:50 ` Will Deacon
2020-11-27 9:49 ` Quentin Perret
2020-11-27 9:49 ` Quentin Perret
2020-11-27 13:19 ` Qais Yousef
2020-11-27 13:19 ` Qais Yousef
2020-12-01 16:56 ` Will Deacon
2020-12-01 16:56 ` Will Deacon
2020-12-02 13:06 ` Qais Yousef
2020-12-02 13:06 ` Qais Yousef
2020-11-24 15:50 ` [PATCH v4 08/14] arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0 Will Deacon
2020-11-24 15:50 ` Will Deacon
2020-11-27 10:01 ` Quentin Perret
2020-11-27 10:01 ` Quentin Perret
2020-11-27 13:23 ` Qais Yousef
2020-11-27 13:23 ` Qais Yousef
2020-12-01 16:55 ` Will Deacon
2020-12-01 16:55 ` Will Deacon
2020-12-02 14:07 ` Qais Yousef
2020-12-02 14:07 ` Qais Yousef
2020-11-24 15:50 ` [PATCH v4 09/14] cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1 Will Deacon
2020-11-24 15:50 ` Will Deacon
2020-11-27 13:32 ` Qais Yousef
2020-11-27 13:32 ` Qais Yousef
2020-11-30 17:05 ` Qais Yousef
2020-11-30 17:05 ` Qais Yousef
2020-11-30 17:36 ` Quentin Perret
2020-11-30 17:36 ` Quentin Perret
2020-12-01 11:58 ` Qais Yousef
2020-12-01 11:58 ` Qais Yousef
2020-12-01 12:37 ` Quentin Perret
2020-12-01 12:37 ` Quentin Perret
2020-12-01 14:11 ` Qais Yousef
2020-12-01 14:11 ` Qais Yousef
2020-12-01 15:56 ` Quentin Perret
2020-12-01 15:56 ` Quentin Perret
2020-12-01 22:30 ` Will Deacon
2020-12-01 22:30 ` Will Deacon
2020-12-02 11:34 ` Qais Yousef [this message]
2020-12-02 11:34 ` Qais Yousef
2020-12-02 11:33 ` Qais Yousef
2020-12-02 11:33 ` Qais Yousef
2020-11-24 15:50 ` [PATCH v4 10/14] sched: Introduce arch_task_cpu_possible_mask() to limit fallback rq selection Will Deacon
2020-11-24 15:50 ` Will Deacon
2020-11-24 15:50 ` [PATCH v4 11/14] sched: Reject CPU affinity changes based on arch_task_cpu_possible_mask() Will Deacon
2020-11-24 15:50 ` Will Deacon
2020-11-27 9:54 ` Quentin Perret
2020-11-27 9:54 ` Quentin Perret
2020-11-24 15:50 ` [PATCH v4 12/14] arm64: Prevent offlining first CPU with 32-bit EL0 on mismatched system Will Deacon
2020-11-24 15:50 ` Will Deacon
2020-11-27 13:41 ` Qais Yousef
2020-11-27 13:41 ` Qais Yousef
2020-12-01 22:13 ` Will Deacon
2020-12-01 22:13 ` Will Deacon
2020-12-02 12:59 ` Qais Yousef
2020-12-02 12:59 ` Qais Yousef
2020-12-02 17:42 ` Will Deacon
2020-12-02 17:42 ` Will Deacon
2020-12-02 18:08 ` Qais Yousef
2020-12-02 18:08 ` Qais Yousef
2020-11-24 15:50 ` [PATCH v4 13/14] arm64: Implement arch_task_cpu_possible_mask() Will Deacon
2020-11-24 15:50 ` Will Deacon
2020-11-27 13:41 ` Qais Yousef
2020-11-27 13:41 ` Qais Yousef
2020-11-24 15:50 ` [PATCH v4 14/14] arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores Will Deacon
2020-11-24 15:50 ` Will Deacon
2020-11-27 13:58 ` [PATCH v4 00/14] An alternative series for asymmetric AArch32 systems Qais Yousef
2020-11-27 13:58 ` Qais Yousef
2020-12-05 20:43 ` Pavel Machek
2020-12-05 20:43 ` Pavel Machek
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