All of lore.kernel.org
 help / color / mirror / Atom feed
From: Will Deacon <will@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
	Will Deacon <will@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>,
	Qais Yousef <qais.yousef@arm.com>,
	Suren Baghdasaryan <surenb@google.com>,
	Quentin Perret <qperret@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: [PATCH v5 00/15] An alternative series for asymmetric AArch32 systems
Date: Tue,  8 Dec 2020 13:28:20 +0000	[thread overview]
Message-ID: <20201208132835.6151-1-will@kernel.org> (raw)

Hi all,

Christmas has come early: it's time for version five of these patches
which have previously appeared here:

  v1: https://lore.kernel.org/r/20201027215118.27003-1-will@kernel.org
  v2: https://lore.kernel.org/r/20201109213023.15092-1-will@kernel.org
  v3: https://lore.kernel.org/r/20201113093720.21106-1-will@kernel.org
  v4: https://lore.kernel.org/r/20201124155039.13804-1-will@kernel.org

and which started life as a reimplementation of some patches from Qais:

  https://lore.kernel.org/r/20201021104611.2744565-1-qais.yousef@arm.com

There's also now a nice writeup on LWN:

  https://lwn.net/Articles/838339/

and rumours of a feature film are doing the rounds.

[subscriber-only, but if you're reading this then you should really
 subscribe.]

The aim of this series is to allow 32-bit ARM applications to run on
arm64 SoCs where not all of the CPUs support the 32-bit instruction set.
Unfortunately, such SoCs are real and will continue to be productised
over the next few years at least. I can assure you that I'm not just
doing this for fun.

Changes in v5 include:

  * Teach cpuset_cpus_allowed() about task_cpu_possible_mask() so that
    we can avoid returning incompatible CPUs for a given task. This
    means that sched_setaffinity() can be used with larger masks (like
    the online mask) from userspace and also allows us to take into
    account the cpuset hierarchy when forcefully overriding the affinity
    for a task on execve().

  * Honour task_cpu_possible_mask() when attaching a task to a cpuset,
    so that the resulting affinity mask does not contain any incompatible
    CPUs (since it would be rejected by set_cpus_allowed_ptr() otherwise).

  * Moved overriding of the affinity mask into the scheduler core rather
    than munge affinity masks directly in the architecture backend.

  * Extended comments and documentation.

  * Some renaming and cosmetic changes.

I'm pretty happy with this now, although it still needs review and will
require rebasing to play nicely with the SCA changes in -next.

Cheers,

Will

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Qais Yousef <qais.yousef@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Quentin Perret <qperret@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: kernel-team@android.com

--->8


Will Deacon (15):
  arm64: cpuinfo: Split AArch32 registers out into a separate struct
  arm64: Allow mismatched 32-bit EL0 support
  KVM: arm64: Kill 32-bit vCPUs on systems with mismatched EL0 support
  arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs
  arm64: Advertise CPUs capable of running 32-bit applications in sysfs
  sched: Introduce task_cpu_possible_mask() to limit fallback rq
    selection
  cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1
  cpuset: Honour task_cpu_possible_mask() in guarantee_online_cpus()
  sched: Reject CPU affinity changes based on task_cpu_possible_mask()
  sched: Introduce force_compatible_cpus_allowed_ptr() to limit CPU
    affinity
  arm64: Implement task_cpu_possible_mask()
  arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit
    EL0
  arm64: Prevent offlining first CPU with 32-bit EL0 on mismatched
    system
  arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0
  arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores

 .../ABI/testing/sysfs-devices-system-cpu      |   9 +
 .../admin-guide/kernel-parameters.txt         |   8 +
 arch/arm64/include/asm/cpu.h                  |  44 ++--
 arch/arm64/include/asm/cpucaps.h              |   3 +-
 arch/arm64/include/asm/cpufeature.h           |   8 +-
 arch/arm64/include/asm/mmu_context.h          |  13 ++
 arch/arm64/kernel/cpufeature.c                | 219 ++++++++++++++----
 arch/arm64/kernel/cpuinfo.c                   |  53 +++--
 arch/arm64/kernel/process.c                   |  19 +-
 arch/arm64/kvm/arm.c                          |  11 +-
 include/linux/cpuset.h                        |   3 +-
 include/linux/mmu_context.h                   |   8 +
 include/linux/sched.h                         |   1 +
 kernel/cgroup/cpuset.c                        |  39 ++--
 kernel/sched/core.c                           | 112 +++++++--
 15 files changed, 426 insertions(+), 124 deletions(-)

-- 
2.29.2.576.ga3fc446d84-goog


WARNING: multiple messages have this Message-ID
From: Will Deacon <will@kernel.org>
To: linux-arm-kernel@lists.infradead.org
Cc: linux-arch@vger.kernel.org, Marc Zyngier <maz@kernel.org>,
	kernel-team@android.com,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Juri Lelli <juri.lelli@redhat.com>,
	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, Qais Yousef <qais.yousef@arm.com>,
	Suren Baghdasaryan <surenb@google.com>,
	Ingo Molnar <mingo@redhat.com>, Li Zefan <lizefan@huawei.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Tejun Heo <tj@kernel.org>, Will Deacon <will@kernel.org>,
	Morten Rasmussen <morten.rasmussen@arm.com>
Subject: [PATCH v5 00/15] An alternative series for asymmetric AArch32 systems
Date: Tue,  8 Dec 2020 13:28:20 +0000	[thread overview]
Message-ID: <20201208132835.6151-1-will@kernel.org> (raw)

Hi all,

Christmas has come early: it's time for version five of these patches
which have previously appeared here:

  v1: https://lore.kernel.org/r/20201027215118.27003-1-will@kernel.org
  v2: https://lore.kernel.org/r/20201109213023.15092-1-will@kernel.org
  v3: https://lore.kernel.org/r/20201113093720.21106-1-will@kernel.org
  v4: https://lore.kernel.org/r/20201124155039.13804-1-will@kernel.org

and which started life as a reimplementation of some patches from Qais:

  https://lore.kernel.org/r/20201021104611.2744565-1-qais.yousef@arm.com

There's also now a nice writeup on LWN:

  https://lwn.net/Articles/838339/

and rumours of a feature film are doing the rounds.

[subscriber-only, but if you're reading this then you should really
 subscribe.]

The aim of this series is to allow 32-bit ARM applications to run on
arm64 SoCs where not all of the CPUs support the 32-bit instruction set.
Unfortunately, such SoCs are real and will continue to be productised
over the next few years at least. I can assure you that I'm not just
doing this for fun.

Changes in v5 include:

  * Teach cpuset_cpus_allowed() about task_cpu_possible_mask() so that
    we can avoid returning incompatible CPUs for a given task. This
    means that sched_setaffinity() can be used with larger masks (like
    the online mask) from userspace and also allows us to take into
    account the cpuset hierarchy when forcefully overriding the affinity
    for a task on execve().

  * Honour task_cpu_possible_mask() when attaching a task to a cpuset,
    so that the resulting affinity mask does not contain any incompatible
    CPUs (since it would be rejected by set_cpus_allowed_ptr() otherwise).

  * Moved overriding of the affinity mask into the scheduler core rather
    than munge affinity masks directly in the architecture backend.

  * Extended comments and documentation.

  * Some renaming and cosmetic changes.

I'm pretty happy with this now, although it still needs review and will
require rebasing to play nicely with the SCA changes in -next.

Cheers,

Will

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Morten Rasmussen <morten.rasmussen@arm.com>
Cc: Qais Yousef <qais.yousef@arm.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Quentin Perret <qperret@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Li Zefan <lizefan@huawei.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Cc: kernel-team@android.com

--->8


Will Deacon (15):
  arm64: cpuinfo: Split AArch32 registers out into a separate struct
  arm64: Allow mismatched 32-bit EL0 support
  KVM: arm64: Kill 32-bit vCPUs on systems with mismatched EL0 support
  arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs
  arm64: Advertise CPUs capable of running 32-bit applications in sysfs
  sched: Introduce task_cpu_possible_mask() to limit fallback rq
    selection
  cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1
  cpuset: Honour task_cpu_possible_mask() in guarantee_online_cpus()
  sched: Reject CPU affinity changes based on task_cpu_possible_mask()
  sched: Introduce force_compatible_cpus_allowed_ptr() to limit CPU
    affinity
  arm64: Implement task_cpu_possible_mask()
  arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit
    EL0
  arm64: Prevent offlining first CPU with 32-bit EL0 on mismatched
    system
  arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0
  arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores

 .../ABI/testing/sysfs-devices-system-cpu      |   9 +
 .../admin-guide/kernel-parameters.txt         |   8 +
 arch/arm64/include/asm/cpu.h                  |  44 ++--
 arch/arm64/include/asm/cpucaps.h              |   3 +-
 arch/arm64/include/asm/cpufeature.h           |   8 +-
 arch/arm64/include/asm/mmu_context.h          |  13 ++
 arch/arm64/kernel/cpufeature.c                | 219 ++++++++++++++----
 arch/arm64/kernel/cpuinfo.c                   |  53 +++--
 arch/arm64/kernel/process.c                   |  19 +-
 arch/arm64/kvm/arm.c                          |  11 +-
 include/linux/cpuset.h                        |   3 +-
 include/linux/mmu_context.h                   |   8 +
 include/linux/sched.h                         |   1 +
 kernel/cgroup/cpuset.c                        |  39 ++--
 kernel/sched/core.c                           | 112 +++++++--
 15 files changed, 426 insertions(+), 124 deletions(-)

-- 
2.29.2.576.ga3fc446d84-goog


_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

             reply	other threads:[~2020-12-08 13:29 UTC|newest]

Thread overview: 58+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-08 13:28 Will Deacon [this message]
2020-12-08 13:28 ` Will Deacon
2020-12-08 13:28 ` [PATCH v5 01/15] arm64: cpuinfo: Split AArch32 registers out into a separate struct Will Deacon
2020-12-08 13:28   ` Will Deacon
2020-12-08 13:28 ` [PATCH v5 02/15] arm64: Allow mismatched 32-bit EL0 support Will Deacon
2020-12-08 13:28   ` Will Deacon
2020-12-08 13:28 ` [PATCH v5 03/15] KVM: arm64: Kill 32-bit vCPUs on systems with mismatched " Will Deacon
2020-12-08 13:28   ` Will Deacon
2020-12-08 13:28 ` [PATCH v5 04/15] arm64: Kill 32-bit applications scheduled on 64-bit-only CPUs Will Deacon
2020-12-08 13:28   ` Will Deacon
2020-12-08 13:28 ` [PATCH v5 05/15] arm64: Advertise CPUs capable of running 32-bit applications in sysfs Will Deacon
2020-12-08 13:28   ` Will Deacon
2020-12-08 13:28 ` [PATCH v5 06/15] sched: Introduce task_cpu_possible_mask() to limit fallback rq selection Will Deacon
2020-12-08 13:28   ` Will Deacon
2020-12-08 13:28 ` [PATCH v5 07/15] cpuset: Don't use the cpu_possible_mask as a last resort for cgroup v1 Will Deacon
2020-12-08 13:28   ` Will Deacon
2020-12-17 12:15   ` Qais Yousef
2020-12-17 12:15     ` Qais Yousef
2020-12-17 13:44     ` Peter Zijlstra
2020-12-17 13:44       ` Peter Zijlstra
2020-12-17 14:59       ` Will Deacon
2020-12-17 14:59         ` Will Deacon
2020-12-17 15:00       ` Qais Yousef
2020-12-17 15:00         ` Qais Yousef
2020-12-08 13:28 ` [PATCH v5 08/15] cpuset: Honour task_cpu_possible_mask() in guarantee_online_cpus() Will Deacon
2020-12-08 13:28   ` Will Deacon
2020-12-28  3:54   ` Suren Baghdasaryan
2020-12-28  3:54     ` Suren Baghdasaryan
2020-12-08 13:28 ` [PATCH v5 09/15] sched: Reject CPU affinity changes based on task_cpu_possible_mask() Will Deacon
2020-12-08 13:28   ` Will Deacon
2020-12-08 13:28 ` [PATCH v5 10/15] sched: Introduce force_compatible_cpus_allowed_ptr() to limit CPU affinity Will Deacon
2020-12-08 13:28   ` Will Deacon
2020-12-28  4:29   ` Suren Baghdasaryan
2020-12-28  4:29     ` Suren Baghdasaryan
2020-12-08 13:28 ` [PATCH v5 11/15] arm64: Implement task_cpu_possible_mask() Will Deacon
2020-12-08 13:28   ` Will Deacon
2020-12-08 13:28 ` [PATCH v5 12/15] arm64: exec: Adjust affinity for compat tasks with mismatched 32-bit EL0 Will Deacon
2020-12-08 13:28   ` Will Deacon
2020-12-08 13:28 ` [PATCH v5 13/15] arm64: Prevent offlining first CPU with 32-bit EL0 on mismatched system Will Deacon
2020-12-08 13:28   ` Will Deacon
2020-12-08 13:28 ` [PATCH v5 14/15] arm64: Hook up cmdline parameter to allow mismatched 32-bit EL0 Will Deacon
2020-12-08 13:28   ` Will Deacon
2020-12-08 13:28 ` [PATCH v5 15/15] arm64: Remove logic to kill 32-bit tasks on 64-bit-only cores Will Deacon
2020-12-08 13:28   ` Will Deacon
2020-12-15 17:36 ` [PATCH v5 00/15] An alternative series for asymmetric AArch32 systems Peter Zijlstra
2020-12-15 17:36   ` Peter Zijlstra
2020-12-15 18:50   ` Will Deacon
2020-12-15 18:50     ` Will Deacon
2020-12-17 10:55     ` Peter Zijlstra
2020-12-17 10:55       ` Peter Zijlstra
2020-12-16 11:16 ` Qais Yousef
2020-12-16 11:16   ` Qais Yousef
2020-12-16 14:14   ` Will Deacon
2020-12-16 14:14     ` Will Deacon
2020-12-16 16:48     ` Qais Yousef
2020-12-16 16:48       ` Qais Yousef
2020-12-16 18:21       ` Suren Baghdasaryan
2020-12-16 18:21         ` Suren Baghdasaryan

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20201208132835.6151-1-will@kernel.org \
    --to=will@kernel.org \
    --cc=catalin.marinas@arm.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=hannes@cmpxchg.org \
    --cc=juri.lelli@redhat.com \
    --cc=kernel-team@android.com \
    --cc=linux-arch@vger.kernel.org \
    --cc=linux-arm-kernel@lists.infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=lizefan@huawei.com \
    --cc=maz@kernel.org \
    --cc=mingo@redhat.com \
    --cc=morten.rasmussen@arm.com \
    --cc=peterz@infradead.org \
    --cc=qais.yousef@arm.com \
    --cc=qperret@google.com \
    --cc=surenb@google.com \
    --cc=tj@kernel.org \
    --cc=vincent.guittot@linaro.org \
    --subject='Re: [PATCH v5 00/15] An alternative series for asymmetric AArch32 systems' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.