tracing: Fix stacktrace of latency tracers (irqsoff and friends)

[linux-flexiantxendom0-3.2.10.git] / kernel / printk.c

diff --git a/kernel/printk.c b/kernel/printk.c
index dfd8f73..b663c2c 100644 (file)
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -44,6 +44,9 @@
 
 #include <asm/uaccess.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/printk.h>
+
 /*
  * Architectures can override it:
  */
@@ -199,7 +202,7 @@ void __init setup_log_buf(int early)
                unsigned long mem;
 
                mem = memblock_alloc(new_log_buf_len, PAGE_SIZE);
-               if (mem == MEMBLOCK_ERROR)
+               if (!mem)
                        return;
                new_log_buf = __va(mem);
        } else {
@@ -521,7 +524,7 @@ static void __call_console_drivers(unsigned start, unsigned end)
        }
 }
 
-static int __read_mostly ignore_loglevel;
+static bool __read_mostly ignore_loglevel;
 
 static int __init ignore_loglevel_setup(char *str)
 {
@@ -532,7 +535,7 @@ static int __init ignore_loglevel_setup(char *str)
 }
 
 early_param("ignore_loglevel", ignore_loglevel_setup);
-module_param_named(ignore_loglevel, ignore_loglevel, bool, S_IRUGO | S_IWUSR);
+module_param(ignore_loglevel, bool, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to"
        "print all kernel messages to the console.");
 
@@ -542,6 +545,8 @@ MODULE_PARM_DESC(ignore_loglevel, "ignore loglevel setting, to"
 static void _call_console_drivers(unsigned start,
                                unsigned end, int msg_log_level)
 {
+       trace_console(&LOG_BUF(0), start, end, log_buf_len);
+
        if ((msg_log_level < console_loglevel || ignore_loglevel) &&
                        console_drivers && start != end) {
                if ((start & LOG_BUF_MASK) > (end & LOG_BUF_MASK)) {
@@ -696,12 +701,15 @@ static void zap_locks(void)
 }
 
 #if defined(CONFIG_PRINTK_TIME)
-static int printk_time = 1;
+static bool printk_time = 1;
 #else
-static int printk_time = 0;
+static bool printk_time = 0;
 #endif
 module_param_named(time, printk_time, bool, S_IRUGO | S_IWUSR);
 
+static bool always_kmsg_dump;
+module_param_named(always_kmsg_dump, always_kmsg_dump, bool, S_IRUGO | S_IWUSR);
+
 /* Check if we have any console registered that can be called early in boot. */
 static int have_callable_console(void)
 {
@@ -1098,7 +1106,7 @@ int update_console_cmdline(char *name, int idx, char *name_new, int idx_new, cha
        return -1;
 }
 
-int console_suspend_enabled = 1;
+bool console_suspend_enabled = 1;
 EXPORT_SYMBOL(console_suspend_enabled);
 
 static int __init console_suspend_disable(char *str)
@@ -1208,13 +1216,27 @@ int is_console_locked(void)
        return console_locked;
 }
 
+/*
+ * Delayed printk facility, for scheduler-internal messages:
+ */
+#define PRINTK_BUF_SIZE                512
+
+#define PRINTK_PENDING_WAKEUP  0x01
+#define PRINTK_PENDING_SCHED   0x02
+
 static DEFINE_PER_CPU(int, printk_pending);
+static DEFINE_PER_CPU(char [PRINTK_BUF_SIZE], printk_sched_buf);
 
 void printk_tick(void)
 {
        if (__this_cpu_read(printk_pending)) {
-               __this_cpu_write(printk_pending, 0);
-               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);
+               }
+               if (pending & PRINTK_PENDING_WAKEUP)
+                       wake_up_interruptible(&log_wait);
        }
 }
 
@@ -1228,7 +1250,7 @@ int printk_needs_cpu(int cpu)
 void wake_up_klogd(void)
 {
        if (waitqueue_active(&log_wait))
-               this_cpu_write(printk_pending, 1);
+               this_cpu_or(printk_pending, PRINTK_PENDING_WAKEUP);
 }
 
 /**
@@ -1292,10 +1314,11 @@ again:
        raw_spin_lock(&logbuf_lock);
        if (con_start != log_end)
                retry = 1;
+       raw_spin_unlock_irqrestore(&logbuf_lock, flags);
+
        if (retry && console_trylock())
                goto again;
 
-       raw_spin_unlock_irqrestore(&logbuf_lock, flags);
        if (wake_klogd)
                wake_up_klogd();
 }
@@ -1620,6 +1643,26 @@ late_initcall(printk_late_init);
 
 #if defined CONFIG_PRINTK
 
+int printk_sched(const char *fmt, ...)
+{
+       unsigned long flags;
+       va_list args;
+       char *buf;
+       int r;
+
+       local_irq_save(flags);
+       buf = __get_cpu_var(printk_sched_buf);
+
+       va_start(args, fmt);
+       r = vsnprintf(buf, PRINTK_BUF_SIZE, fmt, args);
+       va_end(args);
+
+       __this_cpu_or(printk_pending, PRINTK_PENDING_SCHED);
+       local_irq_restore(flags);
+
+       return r;
+}
+
 /*
  * printk rate limiting, lifted from the networking subsystem.
  *
@@ -1731,6 +1774,9 @@ void kmsg_dump(enum kmsg_dump_reason reason)
        unsigned long l1, l2;
        unsigned long flags;
 
+       if ((reason > KMSG_DUMP_OOPS) && !always_kmsg_dump)
+               return;
+
        /* Theoretically, the log could move on after we do this, but
           there's not a lot we can do about that. The new messages
           will overwrite the start of what we dump. */