[PATCH] MIPS: SMP-CPS: Add support for irq migration when CPU offline

[PATCH] MIPS: SMP-CPS: Add support for irq migration when CPU offline

[Wei Li]

Currently we won't migrate irqs when offline CPUs, which has been
implemented on most architectures. That will lead to some devices work
incorrectly if the bound cores are offline.

While that can be easily supported by enabling GENERIC_IRQ_MIGRATION.
But i don't pretty known the reason it was not supported on all MIPS
platforms.

This patch add the support for irq migration on MIPS CPS platform, and
it's tested on the interAptiv processor.

Signed-off-by: Wei Li <liwei391@huawei.com>
---
 arch/mips/Kconfig          | 1 +
 arch/mips/kernel/smp-cps.c | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index a48cb9a71471..8ece19ffe255 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -2510,6 +2510,7 @@ config MIPS_CPS
 	select SYS_SUPPORTS_SCHED_SMT if CPU_MIPSR6
 	select SYS_SUPPORTS_SMP
 	select WEAK_ORDERING
+	select GENERIC_IRQ_MIGRATION if HOTPLUG_CPU
 	help
 	  Select this if you wish to run an SMP kernel across multiple cores
 	  within a MIPS Coherent Processing System. When this option is
diff --git a/arch/mips/kernel/smp-cps.c b/arch/mips/kernel/smp-cps.c
index 3ab433a8e871..26f74f7d7604 100644
--- a/arch/mips/kernel/smp-cps.c
+++ b/arch/mips/kernel/smp-cps.c
@@ -12,6 +12,7 @@
 #include <linux/slab.h>
 #include <linux/smp.h>
 #include <linux/types.h>
+#include <linux/irq.h>
 
 #include <asm/bcache.h>
 #include <asm/mips-cps.h>
@@ -465,6 +466,7 @@ static int cps_cpu_disable(void)
 	smp_mb__after_atomic();
 	set_cpu_online(cpu, false);
 	calculate_cpu_foreign_map();
+	irq_migrate_all_off_this_cpu();
 
 	return 0;
 }
-- 
2.17.1

Re: [PATCH] MIPS: SMP-CPS: Add support for irq migration when CPU offline

[Thomas Bogendoerfer]

On Thu, Dec 03, 2020 at 02:54:43PM +0800, Wei Li wrote:
> Currently we won't migrate irqs when offline CPUs, which has been
> implemented on most architectures. That will lead to some devices work
> incorrectly if the bound cores are offline.
> 
> While that can be easily supported by enabling GENERIC_IRQ_MIGRATION.
> But i don't pretty known the reason it was not supported on all MIPS
> platforms.
> 
> This patch add the support for irq migration on MIPS CPS platform, and
> it's tested on the interAptiv processor.
> 
> Signed-off-by: Wei Li <liwei391@huawei.com>
> ---
>  arch/mips/Kconfig          | 1 +
>  arch/mips/kernel/smp-cps.c | 2 ++
>  2 files changed, 3 insertions(+)

applied to mips-next.

Thomas.

-- 
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