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: [RFC][PATCH v8 2/2] printk: Make wake_up_klogd_work_func() async
Date: Fri, 25 Mar 2016 00:43:23 +0900 [thread overview]
Message-ID: <1458834203-3392-3-git-send-email-sergey.senozhatsky@gmail.com> (raw)
In-Reply-To: <1458834203-3392-1-git-send-email-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: Jan Kara <jack@suse.cz>
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.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 a984c5a..475bfd0 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2812,9 +2812,16 @@ 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.rc3.12.g047057b
next prev parent reply other threads:[~2016-03-24 15:46 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-24 15:43 [RFC][PATCH v8 0/2] printk: Make printk() completely async Sergey Senozhatsky
2016-03-24 15:43 ` [RFC][PATCH v8 1/2] " Sergey Senozhatsky
2016-03-29 9:14 ` Jan Kara
2016-04-01 1:14 ` Sergey Senozhatsky
2016-03-31 11:12 ` Petr Mladek
2016-03-31 11:52 ` Jan Kara
2016-04-04 9:41 ` Petr Mladek
2016-04-04 17:01 ` Sergey Senozhatsky
2016-04-01 1:08 ` Sergey Senozhatsky
2016-04-01 8:59 ` Petr Mladek
2016-04-01 9:36 ` Sergey Senozhatsky
2016-04-01 11:30 ` Petr Mladek
2016-03-24 15:43 ` Sergey Senozhatsky [this message]
2016-03-31 11:14 ` [RFC][PATCH v8 2/2] printk: Make wake_up_klogd_work_func() async Petr Mladek
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1458834203-3392-3-git-send-email-sergey.senozhatsky@gmail.com \
--to=sergey.senozhatsky@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=byungchul.park@lge.com \
--cc=jack@suse.com \
--cc=jack@suse.cz \
--cc=linux-kernel@vger.kernel.org \
--cc=penguin-kernel@I-love.SAKURA.ne.jp \
--cc=pmladek@suse.com \
--cc=sergey.senozhatsky.work@gmail.com \
--cc=tj@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).