From: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Kara <jack@suse.com>, Petr Mladek <pmladek@suse.com>,
Tejun Heo <tj@kernel.org>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
linux-kernel@vger.kernel.org,
Byungchul Park <byungchul.park@lge.com>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Jan Kara <jack@suse.cz>
Subject: [PATCH v12 2/3] printk: Make wake_up_klogd_work_func() async
Date: Fri, 13 May 2016 22:18:47 +0900 [thread overview]
Message-ID: <20160513131848.2087-3-sergey.senozhatsky@gmail.com> (raw)
In-Reply-To: <20160513131848.2087-1-sergey.senozhatsky@gmail.com>
From: Jan Kara <jack@suse.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: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Petr Mladek <pmladek@suse.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 c0e49ff..0fb0c04 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2881,9 +2881,16 @@ 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)
--
2.8.2.372.g63a3502
next prev parent reply other threads:[~2016-05-13 12:21 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-13 13:18 [PATCH v12 0/3] printk: Make printk() completely async Sergey Senozhatsky
2016-05-13 13:18 ` [PATCH v12 1/3] " Sergey Senozhatsky
2016-05-13 13:18 ` Sergey Senozhatsky [this message]
2016-05-13 13:18 ` [PATCH v12 3/3] printk: make printk.synchronous param rw Sergey Senozhatsky
2016-06-09 2:20 ` [PATCH v12 0/3] printk: Make printk() completely async Sergey Senozhatsky
2016-06-29 5:08 ` Sergey Senozhatsky
2016-06-29 5:16 ` Joe Perches
2016-06-29 5:32 ` Sergey Senozhatsky
2016-07-12 16:28 ` Petr Mladek
2016-07-13 7:42 ` Sergey Senozhatsky
2016-07-13 11:14 ` Petr Mladek
2016-07-13 13:24 ` Sergey Senozhatsky
2016-07-13 14:22 ` Petr Mladek
2016-07-11 19:25 ` Viresh Kumar
2016-07-12 15:59 ` Petr Mladek
2016-07-12 16:46 ` Sergey Senozhatsky
2016-07-12 17:04 ` Viresh Kumar
2016-07-13 11:19 ` Petr Mladek
-- strict thread matches above, loose matches on Subject: below --
2016-04-22 13:52 Sergey Senozhatsky
2016-04-22 13:52 ` [PATCH v12 2/3] printk: Make wake_up_klogd_work_func() async Sergey Senozhatsky
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