Merge branch 'nohz/printk-v8' into irq/core

[sfrench/cifs-2.6.git] / kernel / printk.c

diff --git a/kernel/printk.c b/kernel/printk.c
index 19c0d7bcf24a77e0f6de246a30fab029cf3a30cc..0b31715f335a7a8ba1a846fe3b93fe71d97cd8d7 100644 (file)
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -42,6 +42,7 @@
 #include <linux/notifier.h>
 #include <linux/rculist.h>
 #include <linux/poll.h>
+#include <linux/irq_work.h>
 
 #include <asm/uaccess.h>
 
@@ -870,10 +871,11 @@ static size_t print_time(u64 ts, char *buf)
        if (!printk_time)
                return 0;
 
+       rem_nsec = do_div(ts, 1000000000);
+
        if (!buf)
-               return 15;
+               return snprintf(NULL, 0, "[%5lu.000000] ", (unsigned long)ts);
 
-       rem_nsec = do_div(ts, 1000000000);
        return sprintf(buf, "[%5lu.%06lu] ",
                       (unsigned long)ts, rem_nsec / 1000);
 }
@@ -1966,30 +1968,32 @@ int is_console_locked(void)
 static DEFINE_PER_CPU(int, printk_pending);
 static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf);
 
-void printk_tick(void)
+static void wake_up_klogd_work_func(struct irq_work *irq_work)
 {
-       if (__this_cpu_read(printk_pending)) {
-               int pending = __this_cpu_xchg(printk_pending, 0);
-               if (pending & PRINTK_PENDING_SCHED) {
-                       char *buf = __get_cpu_var(printk_sched_buf);
-                       printk(KERN_WARNING "[sched_delayed] %s", buf);
-               }
-               if (pending & PRINTK_PENDING_WAKEUP)
-                       wake_up_interruptible(&log_wait);
+       int pending = __this_cpu_xchg(printk_pending, 0);
+
+       if (pending & PRINTK_PENDING_SCHED) {
+               char *buf = __get_cpu_var(printk_sched_buf);
+               printk(KERN_WARNING "[sched_delayed] %s", buf);
        }
-}
 
-int printk_needs_cpu(int cpu)
-{
-       if (cpu_is_offline(cpu))
-               printk_tick();
-       return __this_cpu_read(printk_pending);
+       if (pending & PRINTK_PENDING_WAKEUP)
+               wake_up_interruptible(&log_wait);
 }
 
+static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) = {
+       .func = wake_up_klogd_work_func,
+       .flags = IRQ_WORK_LAZY,
+};
+
 void wake_up_klogd(void)
 {
-       if (waitqueue_active(&log_wait))
+       preempt_disable();
+       if (waitqueue_active(&log_wait)) {
                this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
+               irq_work_queue(&__get_cpu_var(wake_up_klogd_work));
+       }
+       preempt_enable();
 }
 
 static void console_cont_flush(char *text, size_t size)
@@ -2470,6 +2474,7 @@ int printk_sched(const char *fmt, ...)
        va_end(args);
 
        __this_cpu_or(printk_pending, PRINTK_PENDING_SCHED);
+       irq_work_queue(&__get_cpu_var(wake_up_klogd_work));
        local_irq_restore(flags);
 
        return r;