X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fsoftirq.c;h=44bc103acd7d32fb1ee8d07695249544767c5a8c;hb=81fbc9a5dd000126ef727dcdaea3ef5714d1e898;hp=3e952ee125c9d3388220c8aca444fb33498b7549;hpb=29a07c1eb1ddd861fbf501df25bbc154999d06cb;p=pandora-kernel.git

diff --git a/kernel/softirq.c b/kernel/softirq.c
index 3e952ee125c9..44bc103acd7d 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -194,8 +194,12 @@ void local_bh_enable_ip(unsigned long ip)
 EXPORT_SYMBOL(local_bh_enable_ip);
 
 /*
- * We restart softirq processing for at most 2 ms,
- * and if need_resched() is not set.
+ * We restart softirq processing for at most MAX_SOFTIRQ_RESTART times,
+ * but break the loop if need_resched() is set or after 2 ms.
+ * The MAX_SOFTIRQ_TIME provides a nice upper bound in most cases, but in
+ * certain cases, such as stop_machine(), jiffies may cease to
+ * increment and so we need the MAX_SOFTIRQ_RESTART limit as
+ * well to make sure we eventually return from this method.
  *
  * These limits have been established via experimentation.
  * The two things to balance is latency against fairness -
@@ -203,6 +207,7 @@ EXPORT_SYMBOL(local_bh_enable_ip);
  * should not be able to lock up the box.
  */
 #define MAX_SOFTIRQ_TIME  msecs_to_jiffies(2)
+#define MAX_SOFTIRQ_RESTART 10
 
 asmlinkage void __do_softirq(void)
 {
@@ -210,6 +215,7 @@ asmlinkage void __do_softirq(void)
 	__u32 pending;
 	unsigned long end = jiffies + MAX_SOFTIRQ_TIME;
 	int cpu;
+	int max_restart = MAX_SOFTIRQ_RESTART;
 
 	pending = local_softirq_pending();
 	account_system_vtime(current);
@@ -256,7 +262,8 @@ restart:
 
 	pending = local_softirq_pending();
 	if (pending) {
-		if (time_before(jiffies, end) && !need_resched())
+		if (time_before(jiffies, end) && !need_resched() &&
+		    --max_restart)
 			goto restart;
 
 		wakeup_softirqd();