* Benjamin Herrenschmidt (b...@kernel.crashing.org) wrote:
> 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 <nf...@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.
Yes, sorry. I'll get you a fix for the -rc1 timeframe for sure.
> Cheers,
> Ben.
>
> > > Cc: <sta...@kernel.org>
> > > Signed-off-by: Robert Jennings <r...@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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