linux-kernel - Re: [patch 00/12] thermal/x86_pkg_temp: Sanitize yet another hotplug and locking trainwreck

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Date:   Mon, 21 Nov 2016 23:16:19 +0000
From:   "Pandruvada, Srinivas" <srinivas.pandruvada@...el.com>
To:     "tglx@...utronix.de" <tglx@...utronix.de>
CC:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "Zhang, Rui" <rui.zhang@...el.com>,
        "rt@...utronix.de" <rt@...utronix.de>,
        "edubezval@...il.com" <edubezval@...il.com>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>,
        "x86@...nel.org" <x86@...nel.org>, "bp@...en8.de" <bp@...en8.de>
Subject: Re: [patch 00/12] thermal/x86_pkg_temp: Sanitize yet another
 hotplug and locking trainwreck

On Mon, 2016-11-21 at 22:34 +0100, Thomas Gleixner wrote:
> On Mon, 21 Nov 2016, Pandruvada, Srinivas wrote:

[...]

> Stupid me. I tested putting a socket offline, which works, but did
> not
> check what happens on module removal. Delta fix below. That needs to
> be
> folded into the series as the wreckage already happens before the
> last
> patch.

Your change below fixes the crash issue. Now I tested a case where the
last cpu offlined from a package, it removed thermal zone and added
zone back once any cpu from the package onlined. So this is working.

I want to try to run some workload on those cpu to bump up the
temperature and check interrupts. I am hitting some issue unrelated to
this change may be. I onlined three cpus from the package 1.

[189443.567728] smpboot: Booting Node 1 Processor 15 APIC 0x2e
[189656.625947] smpboot: Booting Node 1 Processor 8 APIC 0x20
[189829.545851] smpboot: Booting Node 1 Processor 24 APIC 0x21

But I can't schedule anything on those CPUs. For example now can't run
turbostat, it complains
"
turbostat: re-initialized with num_cpus 19
Could not migrate to CPU 8
"

Same with

#taskset 0x100 stress -c 1
taskset: failed to set pid 0's affinity: Invalid argument

I am on the latest linux-pm/linux-next tree on this server. I will
switch to latest main line and try.

Thanks,
Srinivas



8<--------------------
--- a/drivers/thermal/x86_pkg_temp_thermal.c
+++ b/drivers/thermal/x86_pkg_temp_thermal.c
@@ -63,6 +63,7 @@ struct pkg_device {
        u32                             msr_pkg_therm_high;
        struct delayed_work             work;
        struct thermal_zone_device      *tzone;
+       struct cpumask                  cpumask;
 };
 
 static struct thermal_zone_params pkg_temp_tz_params = {
@@ -391,6 +392,7 @@ static int pkg_temp_thermal_device_add(u
        rdmsr(MSR_IA32_PACKAGE_THERM_INTERRUPT, pkgdev-
>msr_pkg_therm_low,
              pkgdev->msr_pkg_therm_high);
 
+       cpumask_set_cpu(cpu, &pkgdev->cpumask);
        spin_lock_irq(&pkg_temp_lock);
        packages[pkgid] = pkgdev;
        spin_unlock_irq(&pkg_temp_lock);
@@ -399,13 +401,15 @@ static int pkg_temp_thermal_device_add(u
 
 static int pkg_thermal_cpu_offline(unsigned int cpu)
 {
-       int target = cpumask_any_but(topology_core_cpumask(cpu), cpu);
        struct pkg_device *pkgdev = pkg_temp_thermal_get_dev(cpu);
        bool lastcpu, was_target;
+       int target;
 
        if (!pkgdev)
                return 0;
 
+       target = cpumask_any_but(&pkgdev->cpumask, cpu);
+       cpumask_clear_cpu(cpu, &pkgdev->cpumask);
        lastcpu = target >= nr_cpu_ids;
 
        /*
@@ -492,8 +496,10 @@ static int pkg_thermal_cpu_online(unsign
                return -ENODEV;
 
        /* If the package exists, nothing to do */
-       if (pkgdev)
+       if (pkgdev) {
+               cpumask_set_cpu(cpu, &pkgdev->cpumask);
                return 0;
+       }
        return pkg_temp_thermal_device_add(cpu);
 }