| Message ID | 1606299090-14013-1-git-send-email-yangtiezhu@loongson.cn (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | cbab54d9c2b2a73abe541790df28add14b2385bd |
| Headers | show |
| Series | MIPS: No need to check CPU 0 in {loongson3,bmips,octeon}_cpu_disable() | expand |
On 11/25/2020 2:11 AM, Tiezhu Yang wrote: > After commit 9cce844abf07 ("MIPS: CPU#0 is not hotpluggable"), > c->hotpluggable is 0 for CPU 0 and it will not generate a control > file in sysfs for this CPU: > > [root@linux loongson]# cat /sys/devices/system/cpu/cpu0/online > cat: /sys/devices/system/cpu/cpu0/online: No such file or directory > [root@linux loongson]# echo 0 > /sys/devices/system/cpu/cpu0/online > bash: /sys/devices/system/cpu/cpu0/online: Permission denied > > So no need to check CPU 0 in {loongson3,bmips,octeon}_cpu_disable(), > just remove them. > > Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> > --- > arch/mips/cavium-octeon/smp.c | 3 --- > arch/mips/kernel/smp-bmips.c | 3 --- For smp-bmips.c: Acked-by: Florian Fainelli <f.fainelli@gmail.com>
On Wed, Nov 25, 2020 at 06:11:30PM +0800, Tiezhu Yang wrote: > After commit 9cce844abf07 ("MIPS: CPU#0 is not hotpluggable"), > c->hotpluggable is 0 for CPU 0 and it will not generate a control > file in sysfs for this CPU: > > [root@linux loongson]# cat /sys/devices/system/cpu/cpu0/online > cat: /sys/devices/system/cpu/cpu0/online: No such file or directory > [root@linux loongson]# echo 0 > /sys/devices/system/cpu/cpu0/online > bash: /sys/devices/system/cpu/cpu0/online: Permission denied > > So no need to check CPU 0 in {loongson3,bmips,octeon}_cpu_disable(), > just remove them. > > Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> > --- > arch/mips/cavium-octeon/smp.c | 3 --- > arch/mips/kernel/smp-bmips.c | 3 --- > arch/mips/loongson64/smp.c | 3 --- > 3 files changed, 9 deletions(-) applied to mips-next. Thomas.
Hi, On 2020/11/25 18:11, Tiezhu Yang wrote: > After commit 9cce844abf07 ("MIPS: CPU#0 is not hotpluggable"), Why CPU#0 is not hotpluggable on MIPS? Does that unrealizable? > c->hotpluggable is 0 for CPU 0 and it will not generate a control > file in sysfs for this CPU: > > [root@linux loongson]# cat /sys/devices/system/cpu/cpu0/online > cat: /sys/devices/system/cpu/cpu0/online: No such file or directory > [root@linux loongson]# echo 0 > /sys/devices/system/cpu/cpu0/online > bash: /sys/devices/system/cpu/cpu0/online: Permission denied > > So no need to check CPU 0 in {loongson3,bmips,octeon}_cpu_disable(), missing cps_cpu_disable()? Thanks, Wei > just remove them. > > Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> > --- > arch/mips/cavium-octeon/smp.c | 3 --- > arch/mips/kernel/smp-bmips.c | 3 --- > arch/mips/loongson64/smp.c | 3 --- > 3 files changed, 9 deletions(-) > > diff --git a/arch/mips/cavium-octeon/smp.c b/arch/mips/cavium-octeon/smp.c > index 076db9a..66ce552 100644 > --- a/arch/mips/cavium-octeon/smp.c > +++ b/arch/mips/cavium-octeon/smp.c > @@ -290,9 +290,6 @@ static int octeon_cpu_disable(void) > { > unsigned int cpu = smp_processor_id(); > > - if (cpu == 0) > - return -EBUSY; > - > if (!octeon_bootloader_entry_addr) > return -ENOTSUPP; > > diff --git a/arch/mips/kernel/smp-bmips.c b/arch/mips/kernel/smp-bmips.c > index 1dbfb5a..359b176 100644 > --- a/arch/mips/kernel/smp-bmips.c > +++ b/arch/mips/kernel/smp-bmips.c > @@ -362,9 +362,6 @@ static int bmips_cpu_disable(void) > { > unsigned int cpu = smp_processor_id(); > > - if (cpu == 0) > - return -EBUSY; > - > pr_info("SMP: CPU%d is offline\n", cpu); > > set_cpu_online(cpu, false); > diff --git a/arch/mips/loongson64/smp.c b/arch/mips/loongson64/smp.c > index aa0cd72..b8c1fc3 100644 > --- a/arch/mips/loongson64/smp.c > +++ b/arch/mips/loongson64/smp.c > @@ -544,9 +544,6 @@ static int loongson3_cpu_disable(void) > unsigned long flags; > unsigned int cpu = smp_processor_id(); > > - if (cpu == 0) > - return -EBUSY; > - > set_cpu_online(cpu, false); > calculate_cpu_foreign_map(); > local_irq_save(flags); >
On 12/15/2020 11:26 AM, liwei (GF) wrote: > Hi, > > On 2020/11/25 18:11, Tiezhu Yang wrote: >> After commit 9cce844abf07 ("MIPS: CPU#0 is not hotpluggable"), > Why CPU#0 is not hotpluggable on MIPS? Does that unrealizable? The early discussion is here: https://patchwork.kernel.org/project/linux-mips/patch/1594896024-16624-1-git-send-email-chenhc@lemote.com/ As Jiaxun said, it seems that this is a software limitation. I think the initial aim of commit 9cce844abf07 ("MIPS: CPU#0 is not hotpluggable") is to solve ltp test failure. > >> c->hotpluggable is 0 for CPU 0 and it will not generate a control >> file in sysfs for this CPU: >> >> [root@linux loongson]# cat /sys/devices/system/cpu/cpu0/online >> cat: /sys/devices/system/cpu/cpu0/online: No such file or directory >> [root@linux loongson]# echo 0 > /sys/devices/system/cpu/cpu0/online >> bash: /sys/devices/system/cpu/cpu0/online: Permission denied >> >> So no need to check CPU 0 in {loongson3,bmips,octeon}_cpu_disable(), > missing cps_cpu_disable()? Yes, thank you, let me send a patch to do it. Thanks, Tiezhu > > Thanks, > Wei > >> just remove them. >> >> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> >> --- >> arch/mips/cavium-octeon/smp.c | 3 --- >> arch/mips/kernel/smp-bmips.c | 3 --- >> arch/mips/loongson64/smp.c | 3 --- >> 3 files changed, 9 deletions(-) >> >> diff --git a/arch/mips/cavium-octeon/smp.c b/arch/mips/cavium-octeon/smp.c >> index 076db9a..66ce552 100644 >> --- a/arch/mips/cavium-octeon/smp.c >> +++ b/arch/mips/cavium-octeon/smp.c >> @@ -290,9 +290,6 @@ static int octeon_cpu_disable(void) >> { >> unsigned int cpu = smp_processor_id(); >> >> - if (cpu == 0) >> - return -EBUSY; >> - >> if (!octeon_bootloader_entry_addr) >> return -ENOTSUPP; >> >> diff --git a/arch/mips/kernel/smp-bmips.c b/arch/mips/kernel/smp-bmips.c >> index 1dbfb5a..359b176 100644 >> --- a/arch/mips/kernel/smp-bmips.c >> +++ b/arch/mips/kernel/smp-bmips.c >> @@ -362,9 +362,6 @@ static int bmips_cpu_disable(void) >> { >> unsigned int cpu = smp_processor_id(); >> >> - if (cpu == 0) >> - return -EBUSY; >> - >> pr_info("SMP: CPU%d is offline\n", cpu); >> >> set_cpu_online(cpu, false); >> diff --git a/arch/mips/loongson64/smp.c b/arch/mips/loongson64/smp.c >> index aa0cd72..b8c1fc3 100644 >> --- a/arch/mips/loongson64/smp.c >> +++ b/arch/mips/loongson64/smp.c >> @@ -544,9 +544,6 @@ static int loongson3_cpu_disable(void) >> unsigned long flags; >> unsigned int cpu = smp_processor_id(); >> >> - if (cpu == 0) >> - return -EBUSY; >> - >> set_cpu_online(cpu, false); >> calculate_cpu_foreign_map(); >> local_irq_save(flags); >>
diff --git a/arch/mips/cavium-octeon/smp.c b/arch/mips/cavium-octeon/smp.c index 076db9a..66ce552 100644 --- a/arch/mips/cavium-octeon/smp.c +++ b/arch/mips/cavium-octeon/smp.c @@ -290,9 +290,6 @@ static int octeon_cpu_disable(void) { unsigned int cpu = smp_processor_id(); - if (cpu == 0) - return -EBUSY; - if (!octeon_bootloader_entry_addr) return -ENOTSUPP; diff --git a/arch/mips/kernel/smp-bmips.c b/arch/mips/kernel/smp-bmips.c index 1dbfb5a..359b176 100644 --- a/arch/mips/kernel/smp-bmips.c +++ b/arch/mips/kernel/smp-bmips.c @@ -362,9 +362,6 @@ static int bmips_cpu_disable(void) { unsigned int cpu = smp_processor_id(); - if (cpu == 0) - return -EBUSY; - pr_info("SMP: CPU%d is offline\n", cpu); set_cpu_online(cpu, false); diff --git a/arch/mips/loongson64/smp.c b/arch/mips/loongson64/smp.c index aa0cd72..b8c1fc3 100644 --- a/arch/mips/loongson64/smp.c +++ b/arch/mips/loongson64/smp.c @@ -544,9 +544,6 @@ static int loongson3_cpu_disable(void) unsigned long flags; unsigned int cpu = smp_processor_id(); - if (cpu == 0) - return -EBUSY; - set_cpu_online(cpu, false); calculate_cpu_foreign_map(); local_irq_save(flags);
After commit 9cce844abf07 ("MIPS: CPU#0 is not hotpluggable"), c->hotpluggable is 0 for CPU 0 and it will not generate a control file in sysfs for this CPU: [root@linux loongson]# cat /sys/devices/system/cpu/cpu0/online cat: /sys/devices/system/cpu/cpu0/online: No such file or directory [root@linux loongson]# echo 0 > /sys/devices/system/cpu/cpu0/online bash: /sys/devices/system/cpu/cpu0/online: Permission denied So no need to check CPU 0 in {loongson3,bmips,octeon}_cpu_disable(), just remove them. Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> --- arch/mips/cavium-octeon/smp.c | 3 --- arch/mips/kernel/smp-bmips.c | 3 --- arch/mips/loongson64/smp.c | 3 --- 3 files changed, 9 deletions(-)