X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=kernel%2Fsoftirq.c;h=44bc103acd7d32fb1ee8d07695249544767c5a8c;hb=d46195ebd6bafd899b4324427dea3cd1e6365de7;hp=fca82c32042b73133f2ab74838287c94cf8ad152;hpb=6ad390a25a9d1d8606b9b826878f0a30639dc2b3;p=pandora-kernel.git

diff --git a/kernel/softirq.c b/kernel/softirq.c
index fca82c32042b..44bc103acd7d 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -10,7 +10,7 @@
  *	Remote softirq infrastructure is by Jens Axboe.
  */
 
-#include <linux/module.h>
+#include <linux/export.h>
 #include <linux/kernel_stat.h>
 #include <linux/interrupt.h>
 #include <linux/init.h>
@@ -194,22 +194,28 @@ void local_bh_enable_ip(unsigned long ip)
 EXPORT_SYMBOL(local_bh_enable_ip);
 
 /*
- * We restart softirq processing MAX_SOFTIRQ_RESTART times,
- * and we fall back to softirqd after that.
+ * 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.
  *
- * This number has been established via experimentation.
+ * These limits have been established via experimentation.
  * The two things to balance is latency against fairness -
  * we want to handle softirqs as soon as possible, but they
  * 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)
 {
 	struct softirq_action *h;
 	__u32 pending;
-	int max_restart = MAX_SOFTIRQ_RESTART;
+	unsigned long end = jiffies + MAX_SOFTIRQ_TIME;
 	int cpu;
+	int max_restart = MAX_SOFTIRQ_RESTART;
 
 	pending = local_softirq_pending();
 	account_system_vtime(current);
@@ -255,11 +261,13 @@ restart:
 	local_irq_disable();
 
 	pending = local_softirq_pending();
-	if (pending && --max_restart)
-		goto restart;
+	if (pending) {
+		if (time_before(jiffies, end) && !need_resched() &&
+		    --max_restart)
+			goto restart;
 
-	if (pending)
 		wakeup_softirqd();
+	}
 
 	lockdep_softirq_exit();