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* [PATCH] xen: Add comment for missing FROZEN notifier transitions
@ 2016-04-04 12:32 Anna-Maria Gleixner
  0 siblings, 0 replies; 8+ messages in thread
From: Anna-Maria Gleixner @ 2016-04-04 12:32 UTC (permalink / raw)
  To: linux-kernel
  Cc: xen-devel, Stefano Stabellini, Anna-Maria Gleixner, rt, David Vrabel

Xen guests do not offline/online CPUs during suspend/resume and
therefore FROZEN notifier transitions are not required. Add this
explanation as a comment in the code to get not confused why
CPU_TASKS_FROZEN masked transitions are not considered.

Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Cc: xen-devel@lists.xenproject.org 
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
---
 arch/arm/xen/enlighten.c         |    6 ++++++
 arch/x86/xen/enlighten.c         |    7 +++++++
 drivers/xen/events/events_fifo.c |    6 ++++++
 3 files changed, 19 insertions(+)

--- a/arch/arm/xen/enlighten.c
+++ b/arch/arm/xen/enlighten.c
@@ -213,6 +213,12 @@ static int xen_cpu_notification(struct n
 				unsigned long action,
 				void *hcpu)
 {
+	/*
+	 * Xen guests do not offline/online CPUs during
+	 * suspend/resume, thus CPU_TASKS_FROZEN masked transitions
+	 * are not considered.
+	 */
+
 	switch (action) {
 	case CPU_STARTING:
 		xen_percpu_init();
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1788,6 +1788,13 @@ static int xen_hvm_cpu_notify(struct not
 			      void *hcpu)
 {
 	int cpu = (long)hcpu;
+
+	/*
+	 * Xen guests do not offline/online CPUs during
+	 * suspend/resume, thus CPU_TASKS_FROZEN masked transitions
+	 * are not considered.
+	 */
+
 	switch (action) {
 	case CPU_UP_PREPARE:
 		xen_vcpu_setup(cpu);
--- a/drivers/xen/events/events_fifo.c
+++ b/drivers/xen/events/events_fifo.c
@@ -425,6 +425,12 @@ static int evtchn_fifo_cpu_notification(
 	int cpu = (long)hcpu;
 	int ret = 0;
 
+	/*
+	 * Xen guests do not offline/online CPUs during
+	 * suspend/resume, thus CPU_TASKS_FROZEN masked transitions
+	 * are not considered.
+	*/
+
 	switch (action) {
 	case CPU_UP_PREPARE:
 		if (!per_cpu(cpu_control_block, cpu))

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^ permalink raw reply	[flat|nested] 8+ messages in thread
[parent not found: <1459773140-43707-1-git-send-email-anna-maria@linutronix.de>]

end of thread, other threads:[~2016-04-06 23:53 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-04-04 12:32 [PATCH] xen: Add comment for missing FROZEN notifier transitions Anna-Maria Gleixner
     [not found] <1459773140-43707-1-git-send-email-anna-maria@linutronix.de>
2016-04-04 16:21 ` Julien Grall
     [not found] ` <57029499.7070007@arm.com>
2016-04-04 16:30   ` David Vrabel
     [not found]   ` <570296C3.70805@citrix.com>
2016-04-04 16:48     ` Boris Ostrovsky
     [not found]     ` <57029AC7.90201@oracle.com>
2016-04-05  4:22       ` Juergen Gross
     [not found]       ` <57033D78.8010306@suse.com>
2016-04-06 23:52         ` Stefano Stabellini
2016-04-06 13:09 ` David Vrabel
     [not found] ` <57050A98.80901@cantab.net>
2016-04-06 23:53   ` Stefano Stabellini

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