Re: [RFC PATCH v2 10/14] kernel/watchdog: Add a function to obtain the watchdog_allowed_mask
On Tue, Apr 09, 2019 at 01:34:21PM +0200, Peter Zijlstra wrote: > On Wed, Feb 27, 2019 at 08:05:14AM -0800, Ricardo Neri wrote: > > diff --git a/kernel/watchdog.c b/kernel/watchdog.c > > index 8fbfda94a67b..367aa81294ef 100644 > > --- a/kernel/watchdog.c > > +++ b/kernel/watchdog.c > > @@ -44,7 +44,7 @@ int __read_mostly soft_watchdog_user_enabled = 1; > > int __read_mostly watchdog_thresh = 10; > > int __read_mostly nmi_watchdog_available; > > > > -struct cpumask watchdog_allowed_mask __read_mostly; > > +static struct cpumask watchdog_allowed_mask __read_mostly; > > > > struct cpumask watchdog_cpumask __read_mostly; > > unsigned long *watchdog_cpumask_bits = cpumask_bits(_cpumask); > > Hurmph, more struct cpumask, ideally this would get converted to > cpumask_var_t, I don't think we need this before the allocators work, do > we? I see mm_init() is called before lockup_detector_init(); both from start_kernel(). Thus, IMHO, kzalloc should work at this point. Thanks and BR, Ricardo
Re: [RFC PATCH v2 10/14] kernel/watchdog: Add a function to obtain the watchdog_allowed_mask
On Wed, Feb 27, 2019 at 08:05:14AM -0800, Ricardo Neri wrote: > diff --git a/kernel/watchdog.c b/kernel/watchdog.c > index 8fbfda94a67b..367aa81294ef 100644 > --- a/kernel/watchdog.c > +++ b/kernel/watchdog.c > @@ -44,7 +44,7 @@ int __read_mostly soft_watchdog_user_enabled = 1; > int __read_mostly watchdog_thresh = 10; > int __read_mostly nmi_watchdog_available; > > -struct cpumask watchdog_allowed_mask __read_mostly; > +static struct cpumask watchdog_allowed_mask __read_mostly; > > struct cpumask watchdog_cpumask __read_mostly; > unsigned long *watchdog_cpumask_bits = cpumask_bits(_cpumask); Hurmph, more struct cpumask, ideally this would get converted to cpumask_var_t, I don't think we need this before the allocators work, do we?
Re: [RFC PATCH v2 10/14] kernel/watchdog: Add a function to obtain the watchdog_allowed_mask
On Tue, Mar 26, 2019 at 10:22:40PM +0100, Thomas Gleixner wrote:
> On Wed, 27 Feb 2019, Ricardo Neri wrote:
> >
> > -struct cpumask watchdog_allowed_mask __read_mostly;
> > +static struct cpumask watchdog_allowed_mask __read_mostly;
>
> That hunk is correct.
I'll send a separate patch with this hunk only.
>
> > struct cpumask watchdog_cpumask __read_mostly;
> > unsigned long *watchdog_cpumask_bits = cpumask_bits(_cpumask);
> > @@ -92,6 +92,11 @@ static int __init
> > hardlockup_all_cpu_backtrace_setup(char *str)
> > }
> > __setup("hardlockup_all_cpu_backtrace=",
> > hardlockup_all_cpu_backtrace_setup);
> > # endif /* CONFIG_SMP */
> > +
> > +struct cpumask *watchdog_get_allowed_cpumask(void)
> > +{
> > + return _allowed_mask;
> > +}
>
> That part is pointless as I showed you in the other reply. You don't need
> that mask in your code at all.
Yes. I'll remove this hunk and follow the approach you suggested in your
reply to patch 11.
Thanks and BR,
Ricardo
>
> Thanks,
>
> tglx
>
>
Re: [RFC PATCH v2 10/14] kernel/watchdog: Add a function to obtain the watchdog_allowed_mask
On Wed, 27 Feb 2019, Ricardo Neri wrote:
>
> -struct cpumask watchdog_allowed_mask __read_mostly;
> +static struct cpumask watchdog_allowed_mask __read_mostly;
That hunk is correct.
> struct cpumask watchdog_cpumask __read_mostly;
> unsigned long *watchdog_cpumask_bits = cpumask_bits(_cpumask);
> @@ -92,6 +92,11 @@ static int __init hardlockup_all_cpu_backtrace_setup(char
> *str)
> }
> __setup("hardlockup_all_cpu_backtrace=", hardlockup_all_cpu_backtrace_setup);
> # endif /* CONFIG_SMP */
> +
> +struct cpumask *watchdog_get_allowed_cpumask(void)
> +{
> + return _allowed_mask;
> +}
That part is pointless as I showed you in the other reply. You don't need
that mask in your code at all.
Thanks,
tglx
[RFC PATCH v2 10/14] kernel/watchdog: Add a function to obtain the watchdog_allowed_mask
Implementations of NMI watchdogs that use a single piece of hardware to
monitor all the CPUs in the system (as opposed to per-CPU implementations
such as perf) need to know which CPUs the watchdog is allowed to monitor.
In this manner, non-maskable interrupts are directed only to the monitored
CPUs.
Cc: "H. Peter Anvin"
Cc: Ashok Raj
Cc: Andi Kleen
Cc: Tony Luck
Cc: "Rafael J. Wysocki"
Cc: Don Zickus
Cc: Nicholas Piggin
Cc: Michael Ellerman
Cc: Frederic Weisbecker
Cc: Alexei Starovoitov
Cc: Babu Moger
Cc: Paul Mackerras
Cc: Mathieu Desnoyers
Cc: Masami Hiramatsu
Cc: Peter Zijlstra
Cc: Andrew Morton
Cc: Philippe Ombredanne
Cc: Colin Ian King
Cc: Byungchul Park
Cc: "Paul E. McKenney"
Cc: "Luis R. Rodriguez"
Cc: Waiman Long
Cc: Josh Poimboeuf
Cc: Randy Dunlap
Cc: Davidlohr Bueso
Cc: Christoffer Dall
Cc: Marc Zyngier
Cc: Kai-Heng Feng
Cc: Konrad Rzeszutek Wilk
Cc: David Rientjes
Cc: "Ravi V. Shankar"
Cc: x...@kernel.org
Cc: "David S. Miller"
Cc: Benjamin Herrenschmidt
Cc: sparcli...@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Ricardo Neri
---
include/linux/nmi.h | 1 +
kernel/watchdog.c | 7 ++-
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index bf5ebcfdd590..b563fb6ef21d 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -83,6 +83,7 @@ static inline void reset_hung_task_detector(void) { }
#if defined(CONFIG_HARDLOCKUP_DETECTOR)
extern void hardlockup_detector_disable(void);
+extern struct cpumask *watchdog_get_allowed_cpumask(void);
extern unsigned int hardlockup_panic;
#else
static inline void hardlockup_detector_disable(void) {}
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 8fbfda94a67b..367aa81294ef 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -44,7 +44,7 @@ int __read_mostly soft_watchdog_user_enabled = 1;
int __read_mostly watchdog_thresh = 10;
int __read_mostly nmi_watchdog_available;
-struct cpumask watchdog_allowed_mask __read_mostly;
+static struct cpumask watchdog_allowed_mask __read_mostly;
struct cpumask watchdog_cpumask __read_mostly;
unsigned long *watchdog_cpumask_bits = cpumask_bits(_cpumask);
@@ -92,6 +92,11 @@ static int __init hardlockup_all_cpu_backtrace_setup(char
*str)
}
__setup("hardlockup_all_cpu_backtrace=", hardlockup_all_cpu_backtrace_setup);
# endif /* CONFIG_SMP */
+
+struct cpumask *watchdog_get_allowed_cpumask(void)
+{
+ return _allowed_mask;
+}
#endif /* CONFIG_HARDLOCKUP_DETECTOR */
/*
--
2.17.1
