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authorArnd Bergmann <arnd@arndb.de>2013-06-20 02:06:36 +0200
committerArnd Bergmann <arnd@arndb.de>2013-06-20 02:06:36 +0200
commitd5a51af940efec07c969bdb5fe478bb518116404 (patch)
tree26291e51122081d929e3cac3d441ee5efbfa75d6 /kernel/softirq.c
parentMerge tag 'zynq-dt-for-3.11' of git://git.xilinx.com/linux-xlnx into next/dt (diff)
parentARM: mxs: dt: Add Crystalfontz CFA-10057 device tree (diff)
Merge tag 'mxs-dt-3.11' of git://git.linaro.org/people/shawnguo/linux-2.6 into next/dt
From Shawn Guo: mxs device tree changes for 3.11: * A couple of new board support, cfa10055 and cfa10057 * A few updates on cfa10036 device tree source * Some auart pinctrl data addition * Adopt soc bus infrastructure for mach-mxs * tag 'mxs-dt-3.11' of git://git.linaro.org/people/shawnguo/linux-2.6: ARM: mxs: dt: Add Crystalfontz CFA-10057 device tree ARM: mxs: dt: Add the Crystalfontz CFA-10055 device tree ARM: cfa10049: Switch the chip select pin of the LCD controller ARM: cfa10036: Add USB0 OTG port ARM: dts: apf28dev: Add touchscreen support for APF28dev ARM: mxs: Fix UARTs on M28EVK ARM: cfa10036: dt: Change i2c0 clock frequency ARM: dts: cfa10036: Change the OLED display to SSD1306 ARM: mx28: add auart4 2 pins pinmux to imx28.dtsi ARM: mx28: add auart3 2 pins pinmux to imx28.dtsi ARM: mx28: add auart2 2 pins pinmux to imx28.dtsi ARM: mxs: Use soc bus infrastructure ARM: dts: mx28: Adjust the digctl compatible string ARM: mxs: Remove init_irq declaration in machine description Includes an update to 3.10-rc6 Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'kernel/softirq.c')
-rw-r--r--kernel/softirq.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/kernel/softirq.c b/kernel/softirq.c
index b5197dcb0dad..3d6833f125d3 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -195,8 +195,12 @@ 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 -
@@ -204,6 +208,7 @@ 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)
{
@@ -212,6 +217,7 @@ asmlinkage void __do_softirq(void)
unsigned long end = jiffies + MAX_SOFTIRQ_TIME;
int cpu;
unsigned long old_flags = current->flags;
+ int max_restart = MAX_SOFTIRQ_RESTART;
/*
* Mask out PF_MEMALLOC s current task context is borrowed for the
@@ -265,7 +271,8 @@ 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();