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RFC arm64: initial CPU_HOTPLUG support

Paul Gortmaker linux-arm-kernel 1 version New

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Cover letter [RFC PATCH 0/5] arm64: initial CPU_HOTPLUG support
Quoted 8 lines · Mark Rutland

Hi Catalin, Paul,

I've realised these patches are going to conflict with Paul's "arm64:
delete __cpuinit usage from all users", so I'd like to rebase this series atop of it (removing my cpuinit additions as I do so).

Catalin, would you be happy to create a stable branch at some point soon with Paul's arm64 patch for me to work atop of?

Now that 3.11-rc1 is out, I'll be sending a pull request for phase two of the removal, including the arm64 patch, so that should be mainline very shortly.

Paul.
--

Quoted 70 lines

Thanks,
Mark.

Quoted 65 lines · Mark Rutland

The following patches add basic CPU_HOTPLUG support to arm64, which combined with appropriate firmware (e.g. [1]) can be used to power CPUs up and down dynamically. From discussions at connect it seemed that several people were interested in working in this area, so I thought I'd make my current implementation public now that I've managed to regain access to my inbox.

I've tested this series with the bootwrapper PSCI implementation I've placed on linux-arm.org [1] and a modified foundation model dts with a psci node and each CPU's enable-method set to "psci", using a shell while repeatedly cycling all cpus off and on:

for C in $(seq 0 3); do

	./cyclichotplug.sh $C >/dev/null 2>&1 &

done

---->8----
#!/bin/sh

# cyclichotplug.sh

CPU=$1;

if [ -z "$CPU" ]; then

	printf "Usage: $0 <cpu id>\n";
	exit 1;

fi

ONLINEFILE=/sys/devices/system/cpu/cpu$CPU/online;

while true; do

	echo 0 > $ONLINEFILE;
	echo 1 > $ONLINEFILE;

done
---->8----

Patches are based on v3.10.

Thanks,
Mark.

[1] http://linux-arm.org/git?p=boot-wrapper-aarch64.git;a=shortlog;h=refs/tags/simple-psci

Mark Rutland (5):
arm64: reorganise smp_enable_ops
arm64: factor out spin-table boot method
arm64: read enable-method for CPU0
arm64: add CPU_HOTPLUG infrastructure
arm64: add PSCI CPU_OFF-based hotplug support

 arch/arm64/Kconfig                 |    7 ++
 arch/arm64/include/asm/irq.h       |    1 +
 arch/arm64/include/asm/smp.h       |   37 +++++--
 arch/arm64/kernel/cputable.c       |    2 +-
 arch/arm64/kernel/head.S           |   12 +-
 arch/arm64/kernel/irq.c            |   61 ++++++++++
 arch/arm64/kernel/process.c        |    7 ++
 arch/arm64/kernel/smp.c            |  215 ++++++++++++++++++++++--------------
 arch/arm64/kernel/smp_psci.c       |   54 +++++++--
 arch/arm64/kernel/smp_spin_table.c |   85 +++++++++++++-
 arch/arm64/kernel/vmlinux.lds.S    |    1 -
 11 files changed, 375 insertions(+), 107 deletions(-)
Signature · 1 line
1.7.9.5

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