[PATCH] powerpc: Bring all threads online prior to migration/hibernation
Benjamin Herrenschmidt
benh at kernel.crashing.org
Thu May 2 07:04:56 EST 2013
On Wed, 2013-05-01 at 10:25 -0500, Nathan Fontenot wrote:
> On 04/26/2013 04:32 PM, Robert Jennings wrote:
> > With this patch before a migration/hibernation all threads present but
> > not online will be brought online. After migration/hibernation those
> > threads are taken back offline.
> >
> > During migration/hibernation all online CPUs must call H_JOIN, this is
> > required by the hypervisor. Without this patch, threads that are offline
> > (H_CEDE'd) will not be woken to make the H_JOIN call and the OS will be
> > deadlocked (all threads either JOIN'd or CEDE'd).
> >
>
> This fixes a long standing bug in partition migration.
>
> Acked-by: Nathan Fontenot <nfont at linux.vnet.ibm.com>
I was about to apply this one but had to take it out of my branch as it
breaks the UP build. Can you send a new revision of the patch ? It's a
bug fix, I'll put it in at -rc1.
Cheers,
Ben.
> > Cc: <stable at kernel.org>
> > Signed-off-by: Robert Jennings <rcj at linux.vnet.ibm.com>
> > ---
> > arch/powerpc/include/asm/rtas.h | 2 +
> > arch/powerpc/kernel/rtas.c | 95 ++++++++++++++++++++++++++++++
> > arch/powerpc/platforms/pseries/suspend.c | 22 +++++++
> > 3 files changed, 119 insertions(+)
> >
> > diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h
> > index aef00c6..ee38f29 100644
> > --- a/arch/powerpc/include/asm/rtas.h
> > +++ b/arch/powerpc/include/asm/rtas.h
> > @@ -262,6 +262,8 @@ extern void rtas_progress(char *s, unsigned short hex);
> > extern void rtas_initialize(void);
> > extern int rtas_suspend_cpu(struct rtas_suspend_me_data *data);
> > extern int rtas_suspend_last_cpu(struct rtas_suspend_me_data *data);
> > +extern int rtas_online_cpus_mask(cpumask_var_t cpus);
> > +extern int rtas_offline_cpus_mask(cpumask_var_t cpus);
> > extern int rtas_ibm_suspend_me(struct rtas_args *);
> >
> > struct rtc_time;
> > diff --git a/arch/powerpc/kernel/rtas.c b/arch/powerpc/kernel/rtas.c
> > index 1fd6e7b..855ee98 100644
> > --- a/arch/powerpc/kernel/rtas.c
> > +++ b/arch/powerpc/kernel/rtas.c
> > @@ -19,6 +19,7 @@
> > #include <linux/init.h>
> > #include <linux/capability.h>
> > #include <linux/delay.h>
> > +#include <linux/cpu.h>
> > #include <linux/smp.h>
> > #include <linux/completion.h>
> > #include <linux/cpumask.h>
> > @@ -807,6 +808,77 @@ static void rtas_percpu_suspend_me(void *info)
> > __rtas_suspend_cpu((struct rtas_suspend_me_data *)info, 1);
> > }
> >
> > +enum rtas_cpu_state {
> > + DOWN,
> > + UP,
> > +};
> > +
> > +/* On return cpumask will be altered to indicate CPUs changed */
> > +static int rtas_cpu_state_change_mask(enum rtas_cpu_state state,
> > + cpumask_var_t cpus)
> > +{
> > + int cpu;
> > + int cpuret = 0;
> > + int ret = 0;
> > +
> > + if (cpumask_empty(cpus))
> > + return 0;
> > +
> > + for_each_cpu(cpu, cpus) {
> > + switch (state) {
> > + case DOWN:
> > + cpuret = cpu_down(cpu);
> > + break;
> > + case UP:
> > + cpuret = cpu_up(cpu);
> > + break;
> > + }
> > + if (cpuret) {
> > + pr_debug("%s: cpu_%s for cpu#%d returned %d.\n",
> > + __func__,
> > + ((state == UP) ? "up" : "down"),
> > + cpu, cpuret);
> > + if (!ret)
> > + ret = cpuret;
> > + if (state == UP) {
> > + cpumask_shift_right(cpus, cpus, cpu);
> > + cpumask_shift_left(cpus, cpus, cpu);
> > + break;
> > + } else
> > + cpumask_clear_cpu(cpu, cpus);
> > + }
> > + }
> > +
> > + return ret;
> > +}
> > +
> > +int rtas_online_cpus_mask(cpumask_var_t cpus)
> > +{
> > + int ret;
> > +
> > + ret = rtas_cpu_state_change_mask(UP, cpus);
> > +
> > + if (ret) {
> > + cpumask_var_t tmp_mask;
> > +
> > + if (!alloc_cpumask_var(&tmp_mask, GFP_TEMPORARY))
> > + return ret;
> > +
> > + cpumask_copy(tmp_mask, cpus);
> > + rtas_offline_cpus_mask(tmp_mask);
> > + free_cpumask_var(tmp_mask);
> > + }
> > +
> > + return ret;
> > +}
> > +EXPORT_SYMBOL(rtas_online_cpus_mask);
> > +
> > +int rtas_offline_cpus_mask(cpumask_var_t cpus)
> > +{
> > + return rtas_cpu_state_change_mask(DOWN, cpus);
> > +}
> > +EXPORT_SYMBOL(rtas_offline_cpus_mask);
> > +
> > int rtas_ibm_suspend_me(struct rtas_args *args)
> > {
> > long state;
> > @@ -814,6 +886,8 @@ int rtas_ibm_suspend_me(struct rtas_args *args)
> > unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
> > struct rtas_suspend_me_data data;
> > DECLARE_COMPLETION_ONSTACK(done);
> > + cpumask_var_t offline_mask;
> > + int cpuret;
> >
> > if (!rtas_service_present("ibm,suspend-me"))
> > return -ENOSYS;
> > @@ -837,11 +911,24 @@ int rtas_ibm_suspend_me(struct rtas_args *args)
> > return 0;
> > }
> >
> > + if (!alloc_cpumask_var(&offline_mask, GFP_TEMPORARY))
> > + return -ENOMEM;
> > +
> > atomic_set(&data.working, 0);
> > atomic_set(&data.done, 0);
> > atomic_set(&data.error, 0);
> > data.token = rtas_token("ibm,suspend-me");
> > data.complete = &done;
> > +
> > + /* All present CPUs must be online */
> > + cpumask_andnot(offline_mask, cpu_present_mask, cpu_online_mask);
> > + cpuret = rtas_online_cpus_mask(offline_mask);
> > + if (cpuret) {
> > + pr_err("%s: Could not bring present CPUs online.\n", __func__);
> > + atomic_set(&data.error, cpuret);
> > + goto out;
> > + }
> > +
> > stop_topology_update();
> >
> > /* Call function on all CPUs. One of us will make the
> > @@ -857,6 +944,14 @@ int rtas_ibm_suspend_me(struct rtas_args *args)
> >
> > start_topology_update();
> >
> > + /* Take down CPUs not online prior to suspend */
> > + cpuret = rtas_offline_cpus_mask(offline_mask);
> > + if (cpuret)
> > + pr_warn("%s: Could not restore CPUs to offline state.\n",
> > + __func__);
> > +
> > +out:
> > + free_cpumask_var(offline_mask);
> > return atomic_read(&data.error);
> > }
> > #else /* CONFIG_PPC_PSERIES */
> > diff --git a/arch/powerpc/platforms/pseries/suspend.c b/arch/powerpc/platforms/pseries/suspend.c
> > index 47226e0..5f997e7 100644
> > --- a/arch/powerpc/platforms/pseries/suspend.c
> > +++ b/arch/powerpc/platforms/pseries/suspend.c
> > @@ -16,6 +16,7 @@
> > * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
> > */
> >
> > +#include <linux/cpu.h>
> > #include <linux/delay.h>
> > #include <linux/suspend.h>
> > #include <linux/stat.h>
> > @@ -126,11 +127,15 @@ static ssize_t store_hibernate(struct device *dev,
> > struct device_attribute *attr,
> > const char *buf, size_t count)
> > {
> > + cpumask_var_t offline_mask;
> > int rc;
> >
> > if (!capable(CAP_SYS_ADMIN))
> > return -EPERM;
> >
> > + if (!alloc_cpumask_var(&offline_mask, GFP_TEMPORARY))
> > + return -ENOMEM;
> > +
> > stream_id = simple_strtoul(buf, NULL, 16);
> >
> > do {
> > @@ -140,15 +145,32 @@ static ssize_t store_hibernate(struct device *dev,
> > } while (rc == -EAGAIN);
> >
> > if (!rc) {
> > + /* All present CPUs must be online */
> > + cpumask_andnot(offline_mask, cpu_present_mask,
> > + cpu_online_mask);
> > + rc = rtas_online_cpus_mask(offline_mask);
> > + if (rc) {
> > + pr_err("%s: Could not bring present CPUs online.\n",
> > + __func__);
> > + goto out;
> > + }
> > +
> > stop_topology_update();
> > rc = pm_suspend(PM_SUSPEND_MEM);
> > start_topology_update();
> > +
> > + /* Take down CPUs not online prior to suspend */
> > + if (!rtas_offline_cpus_mask(offline_mask))
> > + pr_warn("%s: Could not restore CPUs to offline "
> > + "state.\n", __func__);
> > }
> >
> > stream_id = 0;
> >
> > if (!rc)
> > rc = count;
> > +out:
> > + free_cpumask_var(offline_mask);
> > return rc;
> > }
> >
>
>
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