Re: [PATCH] drivers/firmware: psci_checker: stash and use topology_core_cpumask for hotplug tests
On Wed, Jul 18, 2018 at 05:49:30PM +0100, Lorenzo Pieralisi wrote:
> On Wed, Jul 18, 2018 at 12:25:32PM +0100, Sudeep Holla wrote:
> > Commit 7f9545aa1a91 ("arm64: smp: remove cpu and numa topology
> > information when hotplugging out CPU") updates the cpu topology when
> > the CPU is hotplugged out. However the PSCI checker code uses the
> > topology_core_cpumask pointers for some of the cpu hotplug testing.
> > Since the pointer to the core_cpumask of the first CPU in the group
> > is used, which when that CPU itself is hotpugged out is just set to
> > itself, the testing terminates after that particular CPU is tested out.
> > But the intention of this tests is to cover all the CPU in the group.
> >
> > In order to support that, we need to stash the topology_core_cpumask
> > before the start of the test and use that value instead of pointer to
> > a cpumask which will be updated on CPU hotplug.
> >
> > Fixes: 7f9545aa1a91a9a4 ("arm64: smp: remove cpu and numa topology
> > information when hotplugging out CPU")
> > Reported-by: Geert Uytterhoeven
> > Tested-by: Geert Uytterhoeven
> > Cc: Mark Rutland
> > Cc: Lorenzo Pieralisi
> > Signed-off-by: Sudeep Holla
> > ---
> > drivers/firmware/psci_checker.c | 30 --
> > 1 file changed, 20 insertions(+), 10 deletions(-)
> >
> > diff --git a/drivers/firmware/psci_checker.c
> > b/drivers/firmware/psci_checker.c
> > index bb1c068bff19..e330c6cb45f5 100644
> > --- a/drivers/firmware/psci_checker.c
> > +++ b/drivers/firmware/psci_checker.c
> > @@ -77,21 +77,23 @@ static int psci_ops_check(void)
> > return 0;
> > }
> >
> > -static int find_cpu_groups(const struct cpumask *cpus,
> > - const struct cpumask **cpu_groups)
> > +static int find_cpu_groups(cpumask_var_t *cpu_groups)
> > {
> > unsigned int nb = 0;
> > cpumask_var_t tmp;
> >
> > if (!alloc_cpumask_var(, GFP_KERNEL))
> > return -ENOMEM;
> > - cpumask_copy(tmp, cpus);
> > + cpumask_copy(tmp, cpu_online_mask);
> >
> > while (!cpumask_empty(tmp)) {
> > const struct cpumask *cpu_group =
> > topology_core_cpumask(cpumask_any(tmp));
> >
> > - cpu_groups[nb++] = cpu_group;
> > + if (cpu_groups && cpu_groups[nb])
> > + cpumask_copy(cpu_groups[nb], cpu_group);
> > +
> > + nb++;
> > cpumask_andnot(tmp, tmp, cpu_group);
> > }
> >
> > @@ -169,25 +171,31 @@ static unsigned int down_and_up_cpus(const struct
> > cpumask *cpus,
> > static int hotplug_tests(void)
> > {
> > int err;
> > - cpumask_var_t offlined_cpus;
> > + cpumask_var_t offlined_cpus, *cpu_groups;
> > int i, nb_cpu_group;
> > - const struct cpumask **cpu_groups;
> > char *page_buf;
> >
> > + /* first run to just get the number of cpu groups */
> > + nb_cpu_group = find_cpu_groups(NULL);
> > +
> > err = -ENOMEM;
> > if (!alloc_cpumask_var(_cpus, GFP_KERNEL))
> > return err;
> > - /* We may have up to nb_available_cpus cpu_groups. */
> > - cpu_groups = kmalloc_array(nb_available_cpus, sizeof(*cpu_groups),
> > - GFP_KERNEL);
> > + cpu_groups = kcalloc(nb_cpu_group, sizeof(cpu_groups), GFP_KERNEL);
> > if (!cpu_groups)
> > goto out_free_cpus;
> > +
> > + for (i = 0; i < nb_cpu_group; ++i)
> > + if (!alloc_cpumask_var(_groups[i], GFP_KERNEL))
> > + goto out_free_cpu_groups;
> > +
> > page_buf = (char *)__get_free_page(GFP_KERNEL);
> > if (!page_buf)
> > goto out_free_cpu_groups;
> >
> > err = 0;
> > - nb_cpu_group = find_cpu_groups(cpu_online_mask, cpu_groups);
> > + /* second run to populate/copy the cpumask */
> > + nb_cpu_group = find_cpu_groups(cpu_groups);
> >
> > /*
> > * Of course the last CPU cannot be powered down and cpu_down() should
> > @@ -212,6 +220,8 @@ static int hotplug_tests(void)
> >
> > free_page((unsigned long)page_buf);
> > out_free_cpu_groups:
> > + for (i = 0; i < nb_cpu_group; ++i)
> > + free_cpumask_var(cpu_groups[i]);
> > kfree(cpu_groups);
> > out_free_cpus:
> > free_cpumask_var(offlined_cpus);
>
> Hi Sudeep,
>
> thanks for the patch. I reckon that adding two functions, say,
> alloc_cpu_groups() and free_cpu_groups() would make the code
> more readable instead of relying on find_cpu_groups() to first
> count then copy; it is for readability rather than correctness.
>
I agree, I can say I was lazy and started trying to keep delta small.
I will respin.
--
Regards,
Sudeep
Re: [PATCH] drivers/firmware: psci_checker: stash and use topology_core_cpumask for hotplug tests
On Wed, Jul 18, 2018 at 12:25:32PM +0100, Sudeep Holla wrote:
> Commit 7f9545aa1a91 ("arm64: smp: remove cpu and numa topology
> information when hotplugging out CPU") updates the cpu topology when
> the CPU is hotplugged out. However the PSCI checker code uses the
> topology_core_cpumask pointers for some of the cpu hotplug testing.
> Since the pointer to the core_cpumask of the first CPU in the group
> is used, which when that CPU itself is hotpugged out is just set to
> itself, the testing terminates after that particular CPU is tested out.
> But the intention of this tests is to cover all the CPU in the group.
>
> In order to support that, we need to stash the topology_core_cpumask
> before the start of the test and use that value instead of pointer to
> a cpumask which will be updated on CPU hotplug.
>
> Fixes: 7f9545aa1a91a9a4 ("arm64: smp: remove cpu and numa topology
> information when hotplugging out CPU")
> Reported-by: Geert Uytterhoeven
> Tested-by: Geert Uytterhoeven
> Cc: Mark Rutland
> Cc: Lorenzo Pieralisi
> Signed-off-by: Sudeep Holla
> ---
> drivers/firmware/psci_checker.c | 30 --
> 1 file changed, 20 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/firmware/psci_checker.c b/drivers/firmware/psci_checker.c
> index bb1c068bff19..e330c6cb45f5 100644
> --- a/drivers/firmware/psci_checker.c
> +++ b/drivers/firmware/psci_checker.c
> @@ -77,21 +77,23 @@ static int psci_ops_check(void)
> return 0;
> }
>
> -static int find_cpu_groups(const struct cpumask *cpus,
> -const struct cpumask **cpu_groups)
> +static int find_cpu_groups(cpumask_var_t *cpu_groups)
> {
> unsigned int nb = 0;
> cpumask_var_t tmp;
>
> if (!alloc_cpumask_var(, GFP_KERNEL))
> return -ENOMEM;
> - cpumask_copy(tmp, cpus);
> + cpumask_copy(tmp, cpu_online_mask);
>
> while (!cpumask_empty(tmp)) {
> const struct cpumask *cpu_group =
> topology_core_cpumask(cpumask_any(tmp));
>
> - cpu_groups[nb++] = cpu_group;
> + if (cpu_groups && cpu_groups[nb])
> + cpumask_copy(cpu_groups[nb], cpu_group);
> +
> + nb++;
> cpumask_andnot(tmp, tmp, cpu_group);
> }
>
> @@ -169,25 +171,31 @@ static unsigned int down_and_up_cpus(const struct
> cpumask *cpus,
> static int hotplug_tests(void)
> {
> int err;
> - cpumask_var_t offlined_cpus;
> + cpumask_var_t offlined_cpus, *cpu_groups;
> int i, nb_cpu_group;
> - const struct cpumask **cpu_groups;
> char *page_buf;
>
> + /* first run to just get the number of cpu groups */
> + nb_cpu_group = find_cpu_groups(NULL);
> +
> err = -ENOMEM;
> if (!alloc_cpumask_var(_cpus, GFP_KERNEL))
> return err;
> - /* We may have up to nb_available_cpus cpu_groups. */
> - cpu_groups = kmalloc_array(nb_available_cpus, sizeof(*cpu_groups),
> -GFP_KERNEL);
> + cpu_groups = kcalloc(nb_cpu_group, sizeof(cpu_groups), GFP_KERNEL);
> if (!cpu_groups)
> goto out_free_cpus;
> +
> + for (i = 0; i < nb_cpu_group; ++i)
> + if (!alloc_cpumask_var(_groups[i], GFP_KERNEL))
> + goto out_free_cpu_groups;
> +
> page_buf = (char *)__get_free_page(GFP_KERNEL);
> if (!page_buf)
> goto out_free_cpu_groups;
>
> err = 0;
> - nb_cpu_group = find_cpu_groups(cpu_online_mask, cpu_groups);
> + /* second run to populate/copy the cpumask */
> + nb_cpu_group = find_cpu_groups(cpu_groups);
>
> /*
>* Of course the last CPU cannot be powered down and cpu_down() should
> @@ -212,6 +220,8 @@ static int hotplug_tests(void)
>
> free_page((unsigned long)page_buf);
> out_free_cpu_groups:
> + for (i = 0; i < nb_cpu_group; ++i)
> + free_cpumask_var(cpu_groups[i]);
> kfree(cpu_groups);
> out_free_cpus:
> free_cpumask_var(offlined_cpus);
Hi Sudeep,
thanks for the patch. I reckon that adding two functions, say,
alloc_cpu_groups() and free_cpu_groups() would make the code
more readable instead of relying on find_cpu_groups() to first
count then copy; it is for readability rather than correctness.
Thanks,
Lorenzo
[PATCH] drivers/firmware: psci_checker: stash and use topology_core_cpumask for hotplug tests
Commit 7f9545aa1a91 ("arm64: smp: remove cpu and numa topology
information when hotplugging out CPU") updates the cpu topology when
the CPU is hotplugged out. However the PSCI checker code uses the
topology_core_cpumask pointers for some of the cpu hotplug testing.
Since the pointer to the core_cpumask of the first CPU in the group
is used, which when that CPU itself is hotpugged out is just set to
itself, the testing terminates after that particular CPU is tested out.
But the intention of this tests is to cover all the CPU in the group.
In order to support that, we need to stash the topology_core_cpumask
before the start of the test and use that value instead of pointer to
a cpumask which will be updated on CPU hotplug.
Fixes: 7f9545aa1a91a9a4 ("arm64: smp: remove cpu and numa topology
information when hotplugging out CPU")
Reported-by: Geert Uytterhoeven
Tested-by: Geert Uytterhoeven
Cc: Mark Rutland
Cc: Lorenzo Pieralisi
Signed-off-by: Sudeep Holla
---
drivers/firmware/psci_checker.c | 30 --
1 file changed, 20 insertions(+), 10 deletions(-)
diff --git a/drivers/firmware/psci_checker.c b/drivers/firmware/psci_checker.c
index bb1c068bff19..e330c6cb45f5 100644
--- a/drivers/firmware/psci_checker.c
+++ b/drivers/firmware/psci_checker.c
@@ -77,21 +77,23 @@ static int psci_ops_check(void)
return 0;
}
-static int find_cpu_groups(const struct cpumask *cpus,
- const struct cpumask **cpu_groups)
+static int find_cpu_groups(cpumask_var_t *cpu_groups)
{
unsigned int nb = 0;
cpumask_var_t tmp;
if (!alloc_cpumask_var(, GFP_KERNEL))
return -ENOMEM;
- cpumask_copy(tmp, cpus);
+ cpumask_copy(tmp, cpu_online_mask);
while (!cpumask_empty(tmp)) {
const struct cpumask *cpu_group =
topology_core_cpumask(cpumask_any(tmp));
- cpu_groups[nb++] = cpu_group;
+ if (cpu_groups && cpu_groups[nb])
+ cpumask_copy(cpu_groups[nb], cpu_group);
+
+ nb++;
cpumask_andnot(tmp, tmp, cpu_group);
}
@@ -169,25 +171,31 @@ static unsigned int down_and_up_cpus(const struct cpumask
*cpus,
static int hotplug_tests(void)
{
int err;
- cpumask_var_t offlined_cpus;
+ cpumask_var_t offlined_cpus, *cpu_groups;
int i, nb_cpu_group;
- const struct cpumask **cpu_groups;
char *page_buf;
+ /* first run to just get the number of cpu groups */
+ nb_cpu_group = find_cpu_groups(NULL);
+
err = -ENOMEM;
if (!alloc_cpumask_var(_cpus, GFP_KERNEL))
return err;
- /* We may have up to nb_available_cpus cpu_groups. */
- cpu_groups = kmalloc_array(nb_available_cpus, sizeof(*cpu_groups),
- GFP_KERNEL);
+ cpu_groups = kcalloc(nb_cpu_group, sizeof(cpu_groups), GFP_KERNEL);
if (!cpu_groups)
goto out_free_cpus;
+
+ for (i = 0; i < nb_cpu_group; ++i)
+ if (!alloc_cpumask_var(_groups[i], GFP_KERNEL))
+ goto out_free_cpu_groups;
+
page_buf = (char *)__get_free_page(GFP_KERNEL);
if (!page_buf)
goto out_free_cpu_groups;
err = 0;
- nb_cpu_group = find_cpu_groups(cpu_online_mask, cpu_groups);
+ /* second run to populate/copy the cpumask */
+ nb_cpu_group = find_cpu_groups(cpu_groups);
/*
* Of course the last CPU cannot be powered down and cpu_down() should
@@ -212,6 +220,8 @@ static int hotplug_tests(void)
free_page((unsigned long)page_buf);
out_free_cpu_groups:
+ for (i = 0; i < nb_cpu_group; ++i)
+ free_cpumask_var(cpu_groups[i]);
kfree(cpu_groups);
out_free_cpus:
free_cpumask_var(offlined_cpus);
--
2.7.4
