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authorLinus Torvalds <torvalds@linux-foundation.org>2013-02-20 02:47:58 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2013-02-20 02:47:58 +0100
commitb7133a9a103655cda254987a3c0975fd9d8c443f (patch)
tree85422ad8c32f1782a2ed3b87b7264b1b3953c105 /kernel/printk.c
parentMerge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kerne... (diff)
parentgenirq: Export enable/disable_percpu_irq() (diff)
downloadlinux-b7133a9a103655cda254987a3c0975fd9d8c443f.tar.xz
linux-b7133a9a103655cda254987a3c0975fd9d8c443f.zip
Merge branch 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull irq core changes from Ingo Molnar: "The biggest changes are the IRQ-work and printk changes from Frederic Weisbecker, which prepare the code for 'full dynticks' (the ability to stop or slow down the periodic tick arbitrarily, not just in idle time as today): - Don't stop tick with irq works pending. This fix is generally useful and concerns archs that can't raise self IPIs. - Flush irq works before CPU offlining. - Introduce "lazy" irq works that can wait for the next tick to be executed, unless it's stopped. - Implement klogd wake up using irq work. This removes the ad-hoc printk_tick()/printk_needs_cpu() hooks and make it working even in dynticks mode. - Cleanups and fixes." * 'irq-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: genirq: Export enable/disable_percpu_irq() arch Kconfig: Remove references to IRQ_PER_CPU irq_work: Remove return value from the irq_work_queue() function genirq: Avoid deadlock in spurious handling printk: Wake up klogd using irq_work irq_work: Make self-IPIs optable irq_work: Warn if there's still work on cpu_down irq_work: Flush work on CPU_DYING irq_work: Don't stop the tick with pending works nohz: Add API to check tick state irq_work: Remove CONFIG_HAVE_IRQ_WORK irq_work: Fix racy check on work pending flag irq_work: Fix racy IRQ_WORK_BUSY flag setting
Diffstat (limited to 'kernel/printk.c')
-rw-r--r--kernel/printk.c36
1 files changed, 20 insertions, 16 deletions
diff --git a/kernel/printk.c b/kernel/printk.c
index 267ce780abe8..f24633afa46a 100644
--- 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>
@@ -1959,30 +1960,32 @@ 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)
@@ -2462,6 +2465,7 @@ 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;