[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <1460050307-3718-3-git-send-email-sergey.senozhatsky@gmail.com>
Date: Fri, 8 Apr 2016 02:31:46 +0900
From: Sergey Senozhatsky <sergey.senozhatsky@...il.com>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Jan Kara <jack@...e.com>, Petr Mladek <pmladek@...e.com>,
Tejun Heo <tj@...nel.org>,
Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>,
linux-kernel@...r.kernel.org,
Byungchul Park <byungchul.park@....com>,
Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
Jan Kara <jack@...e.cz>
Subject: [PATCH v11 2/3] printk: Make wake_up_klogd_work_func() async
From: Jan Kara <jack@...e.cz>
Offload printing of scheduler deferred messages from IRQ context
to a schedulable printing kthread, when possible (the same way we
do it in vprintk_emit()). Otherwise, the CPU can spend unbounded
amount of time doing printing in console_unlock() from IRQ.
Signed-off-by: Jan Kara <jack@...e.cz>
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@...il.com>
Reviewed-by: Petr Mladek <pmladek@...e.com>
---
kernel/printk/printk.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 64a98ea..89f5441 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2820,9 +2820,16 @@ static void wake_up_klogd_work_func(struct irq_work *irq_work)
int pending = __this_cpu_xchg(printk_pending, 0);
if (pending & PRINTK_PENDING_OUTPUT) {
- /* If trylock fails, someone else is doing the printing */
- if (console_trylock())
- console_unlock();
+ if (printk_kthread) {
+ wake_up_process(printk_kthread);
+ } else {
+ /*
+ * If trylock fails, someone else is doing
+ * the printing
+ */
+ if (console_trylock())
+ console_unlock();
+ }
}
if (pending & PRINTK_PENDING_WAKEUP)
--
2.8.0
Powered by blists - more mailing lists