From: Thomas Gleixner <tglx@linutronix.de>
To: Sander Eikelenboom <linux@eikelenboom.it>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
xen-devel@lists.xensource.com, linux-kernel@vger.kernel.org
Subject: Re: [Xen-devel] Regression introduced with 14e568e78f6f80ca1e27256641ddf524c7dbdc51 (stop_machine: Use smpboot threads)
Date: Tue, 26 Feb 2013 18:44:33 +0100 (CET) [thread overview]
Message-ID: <alpine.LFD.2.02.1302261843240.22263@ionos> (raw)
In-Reply-To: <894977724.20130226140702@eikelenboom.it>
On Tue, 26 Feb 2013, Sander Eikelenboom wrote:
> Tuesday, February 26, 2013, 1:36:36 PM, you wrote:
> > On Fri, 22 Feb 2013, Konrad Rzeszutek Wilk wrote:
> >>
> >> I don't know if this is b/c the Xen code is missing something or
> >> expects something that never happend. I hadn't looked at your
> >> patch in any detail (was going to do that on Monday).
> >>
> >> Either way, if I boot a HVM guest with PV extensions (aka PVHVM)
>
> Hmm i'm seeing this booting on baremetal as well.
> (see http://lkml.indiana.edu/hypermail/linux/kernel/1302.3/00836.html)
Ok. I decoded it with the help of Konrad. Does the patch below work
for you as well?
Thanks,
tglx
Index: linux-2.6/include/linux/smpboot.h
===================================================================
--- linux-2.6.orig/include/linux/smpboot.h
+++ linux-2.6/include/linux/smpboot.h
@@ -24,6 +24,9 @@ struct smpboot_thread_data;
* parked (cpu offline)
* @unpark: Optional unpark function, called when the thread is
* unparked (cpu online)
+ * @pre_unpark: Optional unpark function, called before the thread is
+ * unparked (cpu online). This is not guaranteed to be
+ * called on the target cpu of the thread. Careful!
* @selfparking: Thread is not parked by the park function.
* @thread_comm: The base name of the thread
*/
@@ -37,6 +40,7 @@ struct smp_hotplug_thread {
void (*cleanup)(unsigned int cpu, bool online);
void (*park)(unsigned int cpu);
void (*unpark)(unsigned int cpu);
+ void (*pre_unpark)(unsigned int cpu);
bool selfparking;
const char *thread_comm;
};
Index: linux-2.6/kernel/smpboot.c
===================================================================
--- linux-2.6.orig/kernel/smpboot.c
+++ linux-2.6/kernel/smpboot.c
@@ -209,6 +209,8 @@ static void smpboot_unpark_thread(struct
{
struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu);
+ if (ht->pre_unpark)
+ ht->pre_unpark(cpu);
kthread_unpark(tsk);
}
Index: linux-2.6/kernel/stop_machine.c
===================================================================
--- linux-2.6.orig/kernel/stop_machine.c
+++ linux-2.6/kernel/stop_machine.c
@@ -336,7 +336,7 @@ static struct smp_hotplug_thread cpu_sto
.create = cpu_stop_create,
.setup = cpu_stop_unpark,
.park = cpu_stop_park,
- .unpark = cpu_stop_unpark,
+ .pre_unpark = cpu_stop_unpark,
.selfparking = true,
};
next prev parent reply other threads:[~2013-02-26 17:44 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-02-23 1:18 Regression introduced with 14e568e78f6f80ca1e27256641ddf524c7dbdc51 (stop_machine: Use smpboot threads) Konrad Rzeszutek Wilk
2013-02-26 12:36 ` Thomas Gleixner
2013-02-26 13:07 ` [Xen-devel] " Sander Eikelenboom
2013-02-26 17:44 ` Thomas Gleixner [this message]
2013-02-26 20:33 ` Sander Eikelenboom
2013-02-26 21:38 ` [tip:core/urgent] stop_machine: Mark per cpu stopper enabled early tip-bot for Thomas Gleixner
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