From: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Jan Kara <jack@suse.cz>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Viresh Kumar <viresh.kumar@linaro.org>,
Andrew Morton <akpm@linux-foundation.org>,
Jan Kara <jack@suse.com>, Tejun Heo <tj@kernel.org>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Byungchul Park <byungchul.park@lge.com>,
vlevenetz@mm-sol.com,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
Subject: Re: [PATCH v10 1/2] printk: Make printk() completely async
Date: Fri, 26 Aug 2016 17:20:48 +0900 [thread overview]
Message-ID: <20160826082048.GA498@swordfish> (raw)
In-Reply-To: <20160826015641.GA520@swordfish>
On (08/26/16 10:56), Sergey Senozhatsky wrote:
> but every lock we take is potentially dangerous as well.
...
> vprintk_emit()
> {
> alt_printk_enter();
> ...
> log_store();
> ...
> alt_printk_exit();
>
> wakep_up_process() /* direct from async printk,
> or indirect from console_unlock()->up() */
> alt_printk_enter();
> ... enqueue task
> alt_printk_exit();
> }
OTOH, after a very quick thought, up() also takes a spin lock, which
may spindump. so I'll probably prefer to keep the entire alt-printk
thing entirely in printk(). something like this
vprintk_emit()
{
alt_printk_enter()
log_store()
alt_printk_exit()
if (async_printk)
{
alt_printk_enter()
wake_up_process()
alt_printk_exit()
} else {
if (console_trylock()) {
console_unlock()
{
....
alt_printk_enter()
up()
alt_printk_exit()
}
}
}
}
this leaves console_trylock() `unprotected'. so I guess I'll do
something like this:
} else {
int ret;
alt_printk_enter()
ret = console_trylock();
alt_printk_exit()
if (ret)
console_unlock();
}
a bit ugly, but well, it is what it is. will think more about it.
-ss
next prev parent reply other threads:[~2016-08-26 8:20 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-04 16:57 [PATCH v10 0/2] printk: Make printk() completely async Sergey Senozhatsky
2016-04-04 16:57 ` [PATCH v10 1/2] " Sergey Senozhatsky
2016-04-04 22:51 ` Andrew Morton
2016-04-05 5:17 ` Sergey Senozhatsky
2016-04-05 7:39 ` Sergey Senozhatsky
2016-04-06 0:19 ` Sergey Senozhatsky
2016-04-06 8:27 ` Jan Kara
2016-04-07 9:48 ` Sergey Senozhatsky
2016-04-07 12:08 ` Sergey Senozhatsky
2016-04-07 13:15 ` Jan Kara
2016-08-10 21:17 ` Viresh Kumar
2016-08-12 9:44 ` Petr Mladek
2016-08-15 14:26 ` Vladislav Levenetz
2016-08-16 9:04 ` Petr Mladek
2016-08-18 2:27 ` Sergey Senozhatsky
2016-08-18 9:33 ` Petr Mladek
2016-08-18 9:51 ` Sergey Senozhatsky
2016-08-18 10:56 ` Petr Mladek
2016-08-19 6:32 ` Sergey Senozhatsky
2016-08-19 9:54 ` Petr Mladek
2016-08-19 19:00 ` Jan Kara
2016-08-20 5:24 ` Sergey Senozhatsky
2016-08-22 4:15 ` Sergey Senozhatsky
2016-08-23 12:19 ` Petr Mladek
2016-08-24 1:33 ` Sergey Senozhatsky
2016-08-25 21:10 ` Petr Mladek
2016-08-26 1:56 ` Sergey Senozhatsky
2016-08-26 8:20 ` Sergey Senozhatsky [this message]
2016-08-30 9:29 ` Petr Mladek
2016-08-31 2:31 ` Sergey Senozhatsky
2016-08-31 9:38 ` Petr Mladek
2016-08-31 12:52 ` Sergey Senozhatsky
2016-09-01 8:58 ` Petr Mladek
2016-09-02 7:58 ` Sergey Senozhatsky
2016-09-02 15:15 ` Petr Mladek
2016-09-06 7:16 ` Sergey Senozhatsky
2016-08-23 13:03 ` Petr Mladek
2016-08-23 13:48 ` Petr Mladek
2016-04-04 16:57 ` [PATCH v10 2/2] printk: Make wake_up_klogd_work_func() async Sergey Senozhatsky
2016-08-23 3:32 [PATCH v10 1/2] printk: Make printk() completely async Andreas Mohr
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