From: Juergen Gross <jgross@suse.com>
To: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org
Cc: Juergen Gross <jgross@suse.com>,
jeremy@goop.org, jdelvare@suse.com, peterz@infradead.org,
hpa@zytor.com, akataria@vmware.com, x86@kernel.org,
rusty@rustcorp.com.au, virtualization@lists.linux-foundation.org,
chrisw@sous-sol.org, mingo@redhat.com, david.vrabel@citrix.com,
Douglas_Warzecha@dell.com, pali.rohar@gmail.com,
boris.ostrovsky@oracle.com, tglx@linutronix.de,
linux@roeck-us.net
Subject: [PATCH v4 3/6] smp: add function to execute a function synchronously on a cpu
Date: Tue, 5 Apr 2016 07:10:04 +0200 [thread overview]
Message-ID: <1459833007-11618-4-git-send-email-jgross__16054.2849255309$1459833118$gmane$org@suse.com> (raw)
In-Reply-To: <1459833007-11618-1-git-send-email-jgross@suse.com>
On some hardware models (e.g. Dell Studio 1555 laptop) some hardware
related functions (e.g. SMIs) are to be executed on physical cpu 0
only. Instead of open coding such a functionality multiple times in
the kernel add a service function for this purpose. This will enable
the possibility to take special measures in virtualized environments
like Xen, too.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
V4: change return value in case of illegal cpu as requested by Peter Zijlstra
make pinning of vcpu an option as suggested by Peter Zijlstra
V2: instead of manipulating the allowed set of cpus use cpu specific
workqueue as requested by Peter Zijlstra
---
include/linux/smp.h | 2 ++
kernel/smp.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
kernel/up.c | 17 +++++++++++++++++
3 files changed, 69 insertions(+)
diff --git a/include/linux/smp.h b/include/linux/smp.h
index c441407..3b5813b 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -196,4 +196,6 @@ extern void arch_enable_nonboot_cpus_end(void);
void smp_setup_processor_id(void);
+int smp_call_on_cpu(unsigned int cpu, bool pin, int (*func)(void *), void *par);
+
#endif /* __LINUX_SMP_H */
diff --git a/kernel/smp.c b/kernel/smp.c
index 9388064..357458b 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -740,3 +740,53 @@ void wake_up_all_idle_cpus(void)
preempt_enable();
}
EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus);
+
+/**
+ * smp_call_on_cpu - Call a function on a specific cpu
+ *
+ * Used to call a function on a specific cpu and wait for it to return.
+ * Optionally make sure the call is done on a specified physical cpu via vcpu
+ * pinning in order to support virtualized environments.
+ */
+struct smp_call_on_cpu_struct {
+ struct work_struct work;
+ struct completion done;
+ int (*func)(void *);
+ void *data;
+ int ret;
+ int cpu;
+};
+
+static void smp_call_on_cpu_callback(struct work_struct *work)
+{
+ struct smp_call_on_cpu_struct *sscs;
+
+ sscs = container_of(work, struct smp_call_on_cpu_struct, work);
+ if (sscs->cpu >= 0)
+ hypervisor_pin_vcpu(sscs->cpu);
+ sscs->ret = sscs->func(sscs->data);
+ if (sscs->cpu >= 0)
+ hypervisor_pin_vcpu(-1);
+
+ complete(&sscs->done);
+}
+
+int smp_call_on_cpu(unsigned int cpu, bool pin, int (*func)(void *), void *par)
+{
+ struct smp_call_on_cpu_struct sscs = {
+ .work = __WORK_INITIALIZER(sscs.work, smp_call_on_cpu_callback),
+ .done = COMPLETION_INITIALIZER_ONSTACK(sscs.done),
+ .func = func,
+ .data = par,
+ .cpu = pin ? cpu : -1,
+ };
+
+ if (cpu >= nr_cpu_ids)
+ return -ENXIO;
+
+ queue_work_on(cpu, system_wq, &sscs.work);
+ wait_for_completion(&sscs.done);
+
+ return sscs.ret;
+}
+EXPORT_SYMBOL_GPL(smp_call_on_cpu);
diff --git a/kernel/up.c b/kernel/up.c
index 3ccee2b..8266810b 100644
--- a/kernel/up.c
+++ b/kernel/up.c
@@ -83,3 +83,20 @@ void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
preempt_enable();
}
EXPORT_SYMBOL(on_each_cpu_cond);
+
+int smp_call_on_cpu(unsigned int cpu, bool pin, int (*func)(void *), void *par)
+{
+ int ret;
+
+ if (cpu != 0)
+ return -ENXIO;
+
+ if (pin)
+ hypervisor_pin_vcpu(0);
+ ret = func(par);
+ if (pin)
+ hypervisor_pin_vcpu(-1);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(smp_call_on_cpu);
--
2.6.2
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next prev parent reply other threads:[~2016-04-05 5:10 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1459833007-11618-1-git-send-email-jgross@suse.com>
2016-04-05 5:10 ` [PATCH v4 1/6] xen: sync xen header Juergen Gross
2016-04-05 5:10 ` [PATCH v4 2/6] virt, sched: add generic vcpu pinning support Juergen Gross
2016-04-05 5:10 ` Juergen Gross [this message]
2016-04-05 5:10 ` [PATCH v4 4/6] xen: add xen_pin_vcpu() to support calling functions on a dedicated pcpu Juergen Gross
2016-04-05 5:10 ` [PATCH v4 5/6] dcdbas: make use of smp_call_on_cpu() Juergen Gross
2016-04-05 5:10 ` [PATCH v4 6/6] hwmon: use smp_call_on_cpu() for dell-smm i8k Juergen Gross
[not found] ` <1459833007-11618-4-git-send-email-jgross@suse.com>
2016-04-05 8:11 ` [PATCH v4 3/6] smp: add function to execute a function synchronously on a cpu Peter Zijlstra
[not found] ` <20160405081107.GH3448@twins.programming.kicks-ass.net>
2016-04-05 10:05 ` Juergen Gross
[not found] ` <1459833007-11618-2-git-send-email-jgross@suse.com>
2016-04-05 9:34 ` [PATCH v4 1/6] xen: sync xen header David Vrabel
[not found] ` <1459833007-11618-5-git-send-email-jgross@suse.com>
2016-04-05 9:45 ` [PATCH v4 4/6] xen: add xen_pin_vcpu() to support calling functions on a dedicated pcpu David Vrabel
[not found] ` <57038927.1030205@citrix.com>
2016-04-05 10:01 ` Juergen Gross
[not found] ` <57038D0E.1040708@suse.com>
2016-04-05 10:03 ` David Vrabel
[not found] ` <1459833007-11618-7-git-send-email-jgross@suse.com>
2016-04-05 14:54 ` [PATCH v4 6/6] hwmon: use smp_call_on_cpu() for dell-smm i8k Guenter Roeck
[not found] ` <20160405145414.GB27359@roeck-us.net>
2016-04-05 19:31 ` Pali Rohár
[not found] ` <201604052131.52765@pali>
2016-04-21 10:57 ` Pali Rohár
[not found] ` <20160421105724.GK29406@pali>
2016-04-21 13:12 ` Juergen Gross
[not found] ` <5718D1D4.3040309@suse.com>
2016-04-21 13:27 ` Pali Rohár
[not found] ` <20160421132735.GR29406@pali>
2016-05-09 14:37 ` Juergen Gross
[not found] ` <5730A08D.60100@suse.com>
2016-05-12 8:51 ` Pali Rohár
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