From: Steven Rostedt <rostedt@goodmis.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: LKML <linux-kernel@vger.kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>, Brad Mouring <bmouring@ni.com>
Subject: Re: [patch 2/2] rtmutex: Detect changes in the pi lock chain
Date: Fri, 6 Jun 2014 10:25:15 -0400 [thread overview]
Message-ID: <20140606102515.4e2c9574@gandalf.local.home> (raw)
In-Reply-To: <20140605152801.930031935@linutronix.de>
On Thu, 05 Jun 2014 15:28:33 -0000
Thomas Gleixner <tglx@linutronix.de> wrote:
> @@ -536,8 +569,9 @@ static int task_blocks_on_rt_mutex(struc
> {
> struct task_struct *owner = rt_mutex_owner(lock);
> struct rt_mutex_waiter *top_waiter = waiter;
> + struct rt_mutex *next_lock = NULL;
> unsigned long flags;
> - int chain_walk = 0, res;
> + int chain_walk, res;
>
> /*
> * Early deadlock detection. We really don't want the task to
> @@ -569,19 +603,21 @@ static int task_blocks_on_rt_mutex(struc
> if (!owner)
> return 0;
>
> + raw_spin_lock_irqsave(&owner->pi_lock, flags);
> if (waiter == rt_mutex_top_waiter(lock)) {
> - raw_spin_lock_irqsave(&owner->pi_lock, flags);
> rt_mutex_dequeue_pi(owner, top_waiter);
> rt_mutex_enqueue_pi(owner, waiter);
>
> __rt_mutex_adjust_prio(owner);
> if (owner->pi_blocked_on)
> chain_walk = 1;
> - raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
> - }
> - else if (debug_rt_mutex_detect_deadlock(waiter, detect_deadlock))
> + } else if (debug_rt_mutex_detect_deadlock(waiter, detect_deadlock)) {
> chain_walk = 1;
> + }
> + if (owner->pi_blocked_on)
> + next_lock = owner->pi_blocked_on->lock;
>
> + raw_spin_unlock_irqrestore(&owner->pi_lock, flags);
> if (!chain_walk)
> return 0;
Here's another optimization:
/* If the owner is not blocked, no need to walk the chain */
if (!chain_walk || !next_lock)
return 0;
-- Steve
next prev parent reply other threads:[~2014-06-06 14:25 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-05 15:28 [patch 0/2] rtmutex: Sanitze deadlock detection and chain walk Thomas Gleixner
2014-06-05 15:28 ` [patch 1/2] rtmutex: Handle deadlock detection smarter Thomas Gleixner
2014-06-06 1:14 ` Steven Rostedt
2014-06-06 5:41 ` Thomas Gleixner
2014-06-06 2:59 ` Steven Rostedt
2014-06-06 5:40 ` Thomas Gleixner
2014-06-09 16:49 ` [tip:locking/urgent] " tip-bot for Thomas Gleixner
2014-06-05 15:28 ` [patch 2/2] rtmutex: Detect changes in the pi lock chain Thomas Gleixner
2014-06-06 9:48 ` Peter Zijlstra
2014-06-06 9:58 ` Steven Rostedt
2014-06-06 14:25 ` Steven Rostedt [this message]
2014-06-06 14:49 ` Steven Rostedt
2014-06-07 7:31 ` Thomas Gleixner
2014-06-09 16:49 ` [tip:locking/urgent] " tip-bot for Thomas Gleixner
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=20140606102515.4e2c9574@gandalf.local.home \
--to=rostedt@goodmis.org \
--cc=bmouring@ni.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
/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).