From: Byungchul Park <byungchul.park@lge.com>
To: Petr Mladek <pmladek@suse.com>
Cc: Steven Rostedt <rostedt@goodmis.org>,
LKML <linux-kernel@vger.kernel.org>,
akpm@linux-foundation.org, linux-mm@kvack.org,
Cong Wang <xiyou.wangcong@gmail.com>,
Dave Hansen <dave.hansen@intel.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Mel Gorman <mgorman@suse.de>, Michal Hocko <mhocko@kernel.org>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
Vlastimil Babka <vbabka@suse.cz>,
Peter Zijlstra <peterz@infradead.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Jan Kara <jack@suse.cz>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
rostedt@home.goodmis.org, kernel-team@lge.com
Subject: Re: [PATCH v4] printk: Add console owner and waiter logic to load balance console writes
Date: Tue, 28 Nov 2017 10:42:29 +0900 [thread overview]
Message-ID: <20171128014229.GA2899@X58A-UD3R> (raw)
In-Reply-To: <20171124155816.pxp345ch4gevjqjm@pathway.suse.cz>
On Fri, Nov 24, 2017 at 04:58:16PM +0100, Petr Mladek wrote:
> @@ -1797,13 +1797,6 @@ asmlinkage int vprintk_emit(int facility, int level,
> spin_release(&console_owner_dep_map, 1, _THIS_IP_);
> printk_safe_exit_irqrestore(flags);
>
> - /*
> - * The owner passed the console lock to us.
> - * Since we did not spin on console lock, annotate
> - * this as a trylock. Otherwise lockdep will
> - * complain.
> - */
> - mutex_acquire(&console_lock_dep_map, 0, 1, _THIS_IP_);
Hello Petr,
IMHO, it would get unbalanced if you only remove this mutex_acquire().
> console_unlock();
> printk_safe_enter_irqsave(flags);
> }
> @@ -2334,10 +2327,10 @@ void console_unlock(void)
> /* The waiter is now free to continue */
> spin_release(&console_owner_dep_map, 1, _THIS_IP_);
> /*
> - * Hand off console_lock to waiter. The waiter will perform
> - * the up(). After this, the waiter is the console_lock owner.
> + * Hand off console_lock to waiter. After this, the waiter
> + * is the console_lock owner.
> */
> - mutex_release(&console_lock_dep_map, 1, _THIS_IP_);
IMHO, this release() should be moved to somewhere properly.
> + lock_commit_crosslock((struct lockdep_map *)&console_lock_dep_map);
> printk_safe_exit_irqrestore(flags);
> /* Note, if waiter is set, logbuf_lock is not held */
> return;
However, now that cross-release was introduces, lockdep can be applied
to semaphore operations. Actually, I have a plan to do that. I think it
would be better to make semaphore tracked with lockdep and remove all
these manual acquire() and release() here. What do you think about it?
Thanks,
Byungchul
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next prev parent reply other threads:[~2017-11-28 1:42 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-08 15:27 [PATCH v4] printk: Add console owner and waiter logic to load balance console writes Steven Rostedt
2017-11-09 10:12 ` Michal Hocko
2017-11-09 10:22 ` [PATCH v4] printk: Add console owner and waiter logic to loadbalance " Tetsuo Handa
2017-11-09 10:26 ` Michal Hocko
2017-11-09 11:03 ` Tetsuo Handa
2017-11-09 11:31 ` Michal Hocko
2017-11-09 12:07 ` Tetsuo Handa
2017-11-24 15:54 ` [PATCH v4] printk: Add console owner and waiter logic to load balance " Petr Mladek
2017-11-24 15:58 ` Petr Mladek
2017-11-27 8:53 ` Byungchul Park
2017-11-28 1:42 ` Byungchul Park [this message]
2017-12-08 14:00 ` Petr Mladek
2017-12-12 5:39 ` Sergey Senozhatsky
2017-12-12 19:27 ` Steven Rostedt
2017-12-13 1:50 ` Sergey Senozhatsky
2017-12-14 14:34 ` Petr Mladek
2017-12-14 13:51 ` Petr Mladek
2017-11-27 8:48 ` Byungchul Park
2017-11-28 6:23 ` Sergey Senozhatsky
2017-12-22 10:31 ` Petr Mladek
2017-12-22 12:44 ` Steven Rostedt
2018-01-10 12:50 ` Petr Mladek
-- strict thread matches above, loose matches on Subject: below --
2017-11-08 15:13 Steven Rostedt
2017-11-08 15:03 Steven Rostedt
2017-11-08 15:10 ` Steven Rostedt
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