Mailing List Archive

# HG changeset patch
# User Keir Fraser <keir@xen.org>
# Date 1292414816 0
# Node ID 1bec63e5bcfe06af2f04d00a663df14ce53a9718
# Parent ae381a864b4f38edf0c672160091b612346c88d1
Reduce side effects of handling '*' debug key

NMI watchdog should be suppressed when dumping IRQ handlers. Softirqs
should be handled periodically while processing non-IRQ handlers.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
xen-unstable changeset: 22538:a3a29e67aa7e
xen-unstable date: Wed Dec 15 12:04:34 2010 +0000
---
xen/common/keyhandler.c | 9 +++++----
xen/common/softirq.c | 10 ++++++++++
xen/include/xen/softirq.h | 2 ++
3 files changed, 17 insertions(+), 4 deletions(-)

diff -r ae381a864b4f -r 1bec63e5bcfe xen/common/keyhandler.c
--- a/xen/common/keyhandler.c Wed Dec 15 10:47:52 2010 +0000
+++ b/xen/common/keyhandler.c Wed Dec 15 12:06:56 2010 +0000
@@ -375,16 +375,15 @@ static void run_all_nonirq_keyhandlers(u
struct keyhandler *h;
int k;

- console_start_log_everything();
for ( k = 0; k < ARRAY_SIZE(key_table); k++ )
{
+ process_pending_softirqs_nested();
h = key_table[k];
if ( (h == NULL) || !h->diagnostic || h->irq_callback )
continue;
printk("[%c: %s]\n", k, h->desc);
(*h->u.fn)(k);
}
- console_end_log_everything();
}

static DECLARE_TASKLET(run_all_keyhandlers_tasklet,
@@ -395,10 +394,11 @@ static void run_all_keyhandlers(unsigned
struct keyhandler *h;
int k;

+ watchdog_disable();
+
printk("'%c' pressed -> firing all diagnostic keyhandlers\n", key);

/* Fire all the IRQ-context diangostic keyhandlers now */
- console_start_log_everything();
for ( k = 0; k < ARRAY_SIZE(key_table); k++ )
{
h = key_table[k];
@@ -407,7 +407,8 @@ static void run_all_keyhandlers(unsigned
printk("[%c: %s]\n", k, h->desc);
(*h->u.irq_fn)(k, regs);
}
- console_end_log_everything();
+
+ watchdog_enable();

/* Trigger the others from a tasklet in non-IRQ context */
tasklet_schedule(&run_all_keyhandlers_tasklet);
diff -r ae381a864b4f -r 1bec63e5bcfe xen/common/softirq.c
--- a/xen/common/softirq.c Wed Dec 15 10:47:52 2010 +0000
+++ b/xen/common/softirq.c Wed Dec 15 12:06:56 2010 +0000
@@ -54,6 +54,16 @@ void process_pending_softirqs(void)
__do_softirq(1ul<<SCHEDULE_SOFTIRQ);
}

+void process_pending_softirqs_nested(void)
+{
+ ASSERT(!in_irq() && local_irq_is_enabled());
+ /*
+ * Do not enter scheduler as it can preempt the calling context,
+ * and do not run tasklets as we're running one currently.
+ */
+ __do_softirq((1ul<<SCHEDULE_SOFTIRQ) | (1ul<<TASKLET_SOFTIRQ));
+}
+
asmlinkage void do_softirq(void)
{
__do_softirq(0);
diff -r ae381a864b4f -r 1bec63e5bcfe xen/include/xen/softirq.h
--- a/xen/include/xen/softirq.h Wed Dec 15 10:47:52 2010 +0000
+++ b/xen/include/xen/softirq.h Wed Dec 15 12:06:56 2010 +0000
@@ -39,6 +39,8 @@ void raise_softirq(unsigned int nr);
* Use this instead of do_softirq() when you do not want to be preempted.
*/
void process_pending_softirqs(void);
+/* ... and use this instead when running inside a tasklet. */
+void process_pending_softirqs_nested(void);

/*
* TASKLETS -- dynamically-allocatable tasks run in softirq context

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