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@rostedt.homelinux.com, 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
WARNING: multiple messages have this Message-ID (diff)
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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-11-28 1:42 UTC|newest] Thread overview: 47+ 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 2017-11-08 15:27 ` Steven Rostedt 2017-11-09 10:12 ` Michal Hocko 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 10:22 ` Tetsuo Handa 2017-11-09 10:26 ` Michal Hocko 2017-11-09 10:26 ` Michal Hocko 2017-11-09 11:03 ` Tetsuo Handa 2017-11-09 11:03 ` Tetsuo Handa 2017-11-09 11:31 ` Michal Hocko 2017-11-09 11:31 ` Michal Hocko 2017-11-09 12:07 ` Tetsuo Handa 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 15:54 ` Petr Mladek 2017-11-24 15:58 ` Petr Mladek 2017-11-24 15:58 ` Petr Mladek 2017-11-27 8:53 ` Byungchul Park 2017-11-27 8:53 ` Byungchul Park 2017-11-28 1:42 ` Byungchul Park [this message] 2017-11-28 1:42 ` Byungchul Park 2017-12-08 14:00 ` Petr Mladek 2017-12-08 14:00 ` Petr Mladek 2017-12-12 5:39 ` Sergey Senozhatsky 2017-12-12 5:39 ` Sergey Senozhatsky 2017-12-12 19:27 ` Steven Rostedt 2017-12-12 19:27 ` Steven Rostedt 2017-12-13 1:50 ` Sergey Senozhatsky 2017-12-13 1:50 ` Sergey Senozhatsky 2017-12-14 14:34 ` Petr Mladek 2017-12-14 14:34 ` Petr Mladek 2017-12-14 13:51 ` Petr Mladek 2017-12-14 13:51 ` Petr Mladek 2017-11-27 8:48 ` Byungchul Park 2017-11-27 8:48 ` Byungchul Park 2017-11-28 6:23 ` Sergey Senozhatsky 2017-11-28 6:23 ` Sergey Senozhatsky 2017-12-22 10:31 ` Petr Mladek 2017-12-22 10:31 ` Petr Mladek 2017-12-22 12:44 ` Steven Rostedt 2017-12-22 12:44 ` Steven Rostedt 2018-01-10 12:50 ` Petr Mladek 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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