Replace process_pending_timers() with process_pending_softirqs().

This ensures that any critical softirqs are handled in a timely manner
(e.g., TIME_CALIBRATE_SOFTIRQ) while still avoiding being preempted by
the scheduler (by SCHEDULE_SOFTIRQ), which is the reason for avoiding
use of do_softirq() directly.

Signed-off-by: Keir Fraser <keir.fraser@citrix.com>

1 files changed, 14 insertions, 2 deletions

diff --git a/xen/common/softirq.c b/xen/common/softirq.c
index ecf3379388..7b04f36f2d 100644
--- a/xen/common/softirq.c
+++ b/xen/common/softirq.c
@@ -22,7 +22,7 @@ irq_cpustat_t irq_stat[NR_CPUS];
 
 static softirq_handler softirq_handlers[NR_SOFTIRQS];
 
-asmlinkage void do_softirq(void)
+static void __do_softirq(unsigned long ignore_mask)
 {
     unsigned int i, cpu;
     unsigned long pending;
@@ -38,7 +38,7 @@ asmlinkage void do_softirq(void)
         if ( rcu_pending(cpu) )
             rcu_check_callbacks(cpu);
 
-        if ( (pending = softirq_pending(cpu)) == 0 )
+        if ( (pending = (softirq_pending(cpu) & ~ignore_mask)) == 0 )
             break;
 
         i = find_first_set_bit(pending);
@@ -47,6 +47,18 @@ asmlinkage void do_softirq(void)
     }
 }
 
+void process_pending_softirqs(void)
+{
+    ASSERT(!in_irq() && local_irq_is_enabled());
+    /* Do not enter scheduler as it can preempt the calling context. */
+    __do_softirq(1ul<<SCHEDULE_SOFTIRQ);
+}
+
+asmlinkage void do_softirq(void)
+{
+    __do_softirq(0);
+}
+
 void open_softirq(int nr, softirq_handler handler)
 {
     ASSERT(nr < NR_SOFTIRQS);