From: Juergen Gross <jgross@suse.com>
To: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org
Cc: Juergen Gross <jgross@suse.com>,
jdelvare@suse.com, peterz@infradead.org, hpa@zytor.com,
x86@kernel.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 2/6] sched: add function to execute a function synchronously on a physical cpu
Date: Fri, 11 Mar 2016 12:59:30 +0100 [thread overview]
Message-ID: <1457697574-6710-3-git-send-email-jgross__22583.2922537395$1457697673$gmane$org@suse.com> (raw)
In-Reply-To: <1457697574-6710-1-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>
---
include/linux/sched.h | 9 +++++++++
kernel/sched/core.c | 26 ++++++++++++++++++++++++++
2 files changed, 35 insertions(+)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index a10494a..dfadf1a 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2247,6 +2247,7 @@ extern void do_set_cpus_allowed(struct task_struct *p,
extern int set_cpus_allowed_ptr(struct task_struct *p,
const struct cpumask *new_mask);
+int call_sync_on_phys_cpu(unsigned cpu, int (*func)(void *), void *par);
#else
static inline void do_set_cpus_allowed(struct task_struct *p,
const struct cpumask *new_mask)
@@ -2259,6 +2260,14 @@ static inline int set_cpus_allowed_ptr(struct task_struct *p,
return -EINVAL;
return 0;
}
+static inline int call_sync_on_phys_cpu(unsigned cpu, int (*func)(void *),
+ void *par)
+{
+ if (cpu != 0)
+ return -EINVAL;
+
+ return func(par);
+}
#endif
#ifdef CONFIG_NO_HZ_COMMON
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 41f6b22..cb9955f 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1265,6 +1265,32 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
}
EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
+int call_sync_on_phys_cpu(unsigned cpu, int (*func)(void *), void *par)
+{
+ cpumask_var_t old_mask;
+ int ret;
+
+ if (cpu >= nr_cpu_ids)
+ return -EINVAL;
+
+ if (!alloc_cpumask_var(&old_mask, GFP_KERNEL))
+ return -ENOMEM;
+
+ cpumask_copy(old_mask, ¤t->cpus_allowed);
+ ret = set_cpus_allowed_ptr(current, cpumask_of(cpu));
+ if (ret)
+ goto out;
+
+ ret = func(par);
+
+ set_cpus_allowed_ptr(current, old_mask);
+
+out:
+ free_cpumask_var(old_mask);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(call_sync_on_phys_cpu);
+
void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
{
#ifdef CONFIG_SCHED_DEBUG
--
2.6.2
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next prev parent reply other threads:[~2016-03-11 11:59 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1457697574-6710-1-git-send-email-jgross@suse.com>
2016-03-11 11:59 ` [PATCH 1/6] xen: sync xen header Juergen Gross
2016-03-11 11:59 ` Juergen Gross [this message]
2016-03-11 11:59 ` [PATCH 3/6] dcdbas: make use of call_sync_on_phys_cpu() Juergen Gross
2016-03-11 11:59 ` [PATCH 4/6] hwmon: use call_sync_on_phys_cpu() for dell-smm i8k Juergen Gross
2016-03-11 11:59 ` [PATCH 5/6] virt, sched: add cpu pinning to call_sync_on_phys_cpu() Juergen Gross
2016-03-11 11:59 ` [PATCH 6/6] xen: add xen_pin_vcpu() to support calling functions on a dedicated pcpu Juergen Gross
[not found] ` <1457697574-6710-3-git-send-email-jgross@suse.com>
2016-03-11 12:19 ` [PATCH 2/6] sched: add function to execute a function synchronously on a physical cpu Peter Zijlstra
[not found] ` <20160311121950.GZ6344@twins.programming.kicks-ass.net>
2016-03-11 12:42 ` Peter Zijlstra
2016-03-11 12:43 ` Juergen Gross
[not found] ` <56E2BD89.4020400@suse.com>
2016-03-11 12:45 ` Peter Zijlstra
[not found] ` <20160311124238.GN6375@twins.programming.kicks-ass.net>
2016-03-11 12:48 ` Juergen Gross
[not found] ` <56E2BE8C.9030309@suse.com>
2016-03-11 12:57 ` Peter Zijlstra
[not found] ` <20160311125706.GC6344@twins.programming.kicks-ass.net>
2016-03-11 13:07 ` Juergen Gross
2016-03-11 12:25 ` [PATCH 0/6] Support calling functions on dedicated " Peter Zijlstra
[not found] ` <20160311122514.GA6344@twins.programming.kicks-ass.net>
2016-03-11 12:28 ` Pali Rohár
2016-03-11 13:15 ` One Thousand Gnomes
2016-03-11 13:19 ` Peter Zijlstra
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