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Message-ID: <20160811144427.j4j3n42eufomtnid@linutronix.de>
Date: Thu, 11 Aug 2016 16:44:27 +0200
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
To: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc: linux-kernel@...r.kernel.org, tglx@...utronix.de, jgross@...e.com,
torvalds@...ux-foundation.org, mingo@...nel.org, hpa@...or.com,
peterz@...radead.org, anna-maria@...utronix.de
Subject: Re: [tip:smp/hotplug] cpu/hotplug: Prevent alloc/free of irq
descriptors during CPU up/down (again)
On 2016-08-11 10:30:57 [-0400], Boris Ostrovsky wrote:
> So you must have converted Xen code already then? Can you post those
> patches (not all 1285, just Xen-related, assuming there are no
> dependencies) and I'll see if I can add them to this series?
This is patch 77. I *hope* the only clash (if any) will be in
cpuhotplug.h. I did not yet retest things in terms of apply & compile.
I plan to do so within this + next week. If you want to test it right
away, please do so :)
From: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Date: Wed, 4 Nov 2015 21:06:00 +0100
Subject: [PATCH] xen: events: fifo: Convert to hotplug state machine
Install the callbacks via the state machine. In theory we could remove the
upper call evtchn_fifo_alloc_control_block() and have callback invoked for
all online CPUs but this does not reflect the currect code.
Cc: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
Cc: Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc: David Vrabel <david.vrabel@...rix.com>
Cc: xen-devel@...ts.xenproject.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
---
drivers/xen/events/events_fifo.c | 33 +++++++++++----------------------
include/linux/cpuhotplug.h | 1 +
2 files changed, 12 insertions(+), 22 deletions(-)
--- a/drivers/xen/events/events_fifo.c
+++ b/drivers/xen/events/events_fifo.c
@@ -418,30 +418,18 @@ static int evtchn_fifo_alloc_control_blo
return ret;
}
-static int evtchn_fifo_cpu_notification(struct notifier_block *self,
- unsigned long action,
- void *hcpu)
+static int xen_evtchn_cpu_prepare(unsigned int cpu)
{
- int cpu = (long)hcpu;
- int ret = 0;
-
- switch (action) {
- case CPU_UP_PREPARE:
- if (!per_cpu(cpu_control_block, cpu))
- ret = evtchn_fifo_alloc_control_block(cpu);
- break;
- case CPU_DEAD:
- __evtchn_fifo_handle_events(cpu, true);
- break;
- default:
- break;
- }
- return ret < 0 ? NOTIFY_BAD : NOTIFY_OK;
+ if (!per_cpu(cpu_control_block, cpu))
+ return evtchn_fifo_alloc_control_block(cpu);
+ return 0;
}
-static struct notifier_block evtchn_fifo_cpu_notifier = {
- .notifier_call = evtchn_fifo_cpu_notification,
-};
+static int xen_evtchn_cpu_dead(unsigned int cpu)
+{
+ __evtchn_fifo_handle_events(cpu, true);
+ return 0;
+}
int __init xen_evtchn_fifo_init(void)
{
@@ -456,7 +444,8 @@ int __init xen_evtchn_fifo_init(void)
evtchn_ops = &evtchn_ops_fifo;
- register_cpu_notifier(&evtchn_fifo_cpu_notifier);
+ cpuhp_setup_state_nocalls(CPUHP_XEN_EV_PREPEARE, "XEN_EV_PREPEARE",
+ xen_evtchn_cpu_prepare, xen_evtchn_cpu_dead);
out:
put_cpu();
return ret;
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -22,6 +22,7 @@ enum cpuhp_state {
CPUHP_SMPCFD_PREPARE,
CPUHP_RELAY_PREPARE,
CPUHP_SLAB_PREPARE,
+ CPUHP_XEN_EV_PREPEARE,
CPUHP_TIMERS_DEAD,
CPUHP_SLUB_DEAD,
CPUHP_MM_WRITEBACK_DEAD,
Sebastian
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