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| author | Thomas Gleixner <tglx@linutronix.de> | 2018-07-07 11:40:18 +0200 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2018-07-09 09:19:18 +0200 |
| commit | 215af5499d9e2b55f111d2431ea20218115f29b3 (patch) | |
| tree | ea2ebc1bdb9efd77714acf5dd26dadcbfe215c70 /kernel/cpu.c | |
| parent | 390d975e0c4e60ce70d4157e0dd91ede37824603 (diff) | |
| download | linux-stable-215af5499d9e2b55f111d2431ea20218115f29b3.tar.gz linux-stable-215af5499d9e2b55f111d2431ea20218115f29b3.tar.bz2 linux-stable-215af5499d9e2b55f111d2431ea20218115f29b3.zip | |
cpu/hotplug: Online siblings when SMT control is turned on
Writing 'off' to /sys/devices/system/cpu/smt/control offlines all SMT
siblings. Writing 'on' merily enables the abilify to online them, but does
not online them automatically.
Make 'on' more useful by onlining all offline siblings.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/cpu.c')
| -rw-r--r-- | kernel/cpu.c | 26 |
1 files changed, 24 insertions, 2 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index 5a00ebdf98c6..d79e24df2420 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -1979,6 +1979,15 @@ static void cpuhp_offline_cpu_device(unsigned int cpu) kobject_uevent(&dev->kobj, KOBJ_OFFLINE); } +static void cpuhp_online_cpu_device(unsigned int cpu) +{ + struct device *dev = get_cpu_device(cpu); + + dev->offline = false; + /* Tell user space about the state change */ + kobject_uevent(&dev->kobj, KOBJ_ONLINE); +} + static int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) { int cpu, ret = 0; @@ -2011,11 +2020,24 @@ static int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval) return ret; } -static void cpuhp_smt_enable(void) +static int cpuhp_smt_enable(void) { + int cpu, ret = 0; + cpu_maps_update_begin(); cpu_smt_control = CPU_SMT_ENABLED; + for_each_present_cpu(cpu) { + /* Skip online CPUs and CPUs on offline nodes */ + if (cpu_online(cpu) || !node_online(cpu_to_node(cpu))) + continue; + ret = _cpu_up(cpu, 0, CPUHP_ONLINE); + if (ret) + break; + /* See comment in cpuhp_smt_disable() */ + cpuhp_online_cpu_device(cpu); + } cpu_maps_update_done(); + return ret; } static ssize_t @@ -2046,7 +2068,7 @@ store_smt_control(struct device *dev, struct device_attribute *attr, if (ctrlval != cpu_smt_control) { switch (ctrlval) { case CPU_SMT_ENABLED: - cpuhp_smt_enable(); + ret = cpuhp_smt_enable(); break; case CPU_SMT_DISABLED: case CPU_SMT_FORCE_DISABLED: |