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From: Peter Zijlstra <peterz@infradead.org>
To: Manfred Spraul <manfred@colorfullife.com>
Cc: Boqun Feng <boqun.feng@gmail.com>,
	Davidlohr Bueso <dave@stgolabs.net>,
	Waiman.Long@hpe.com, mingo@kernel.org,
	torvalds@linux-foundation.org, ggherdovich@suse.com,
	mgorman@techsingularity.net, linux-kernel@vger.kernel.org,
	Paul McKenney <paulmck@linux.vnet.ibm.com>,
	Will Deacon <will.deacon@arm.com>
Subject: Re: sem_lock() vs qspinlocks
Date: Sun, 22 May 2016 11:38:28 +0200	[thread overview]
Message-ID: <20160522093828.GM3193@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <48cb5e2c-f346-d702-30af-2a6666886df4@colorfullife.com>

On Sun, May 22, 2016 at 10:43:08AM +0200, Manfred Spraul wrote:
> How would we handle mixed spin_lock()/mutex_lock() code?
> For the IPC code, I would like to replace the outer lock with a mutex.
> The code only uses spinlocks, because at the time it was written, the mutex
> code didn't contain a busy wait.
> With a mutex, the code would become simpler (all the
> lock/unlock/kmalloc/relock parts could be removed).
> 
> The result would be something like:
> 
> 	mutex_lock(A)			spin_lock(B)
> 	spin_unlock_wait(B)		if (!mutex_is_locked(A))
> 	do_something()			  do_something()
> 

Should work similarly, but we'll have to audit mutex for these same
issues. I'll put it on todo.

  reply	other threads:[~2016-05-22  9:38 UTC|newest]

Thread overview: 41+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-20  5:39 sem_lock() vs qspinlocks Davidlohr Bueso
2016-05-20  7:49 ` Peter Zijlstra
2016-05-20 15:00   ` Davidlohr Bueso
2016-05-20 15:05     ` Peter Zijlstra
2016-05-20 15:25       ` Davidlohr Bueso
2016-05-20 15:28       ` Peter Zijlstra
2016-05-20 20:47     ` Waiman Long
2016-05-20 20:52       ` Peter Zijlstra
2016-05-21  0:59         ` Davidlohr Bueso
2016-05-21  4:01           ` Waiman Long
2016-05-21  7:40             ` Peter Zijlstra
2016-05-20  7:53 ` Peter Zijlstra
2016-05-20  8:13 ` Peter Zijlstra
2016-05-20  8:18   ` Peter Zijlstra
2016-05-20  9:07     ` Giovanni Gherdovich
2016-05-20  9:34       ` Peter Zijlstra
2016-05-20  8:30 ` Peter Zijlstra
2016-05-20  9:00   ` Peter Zijlstra
2016-05-20 10:09     ` Ingo Molnar
2016-05-20 10:45       ` Mel Gorman
2016-05-20 11:58 ` Peter Zijlstra
2016-05-20 14:05   ` Boqun Feng
2016-05-20 15:21     ` Peter Zijlstra
2016-05-20 16:04       ` Peter Zijlstra
2016-05-20 17:00         ` Linus Torvalds
2016-05-20 21:06           ` Peter Zijlstra
2016-05-20 21:44             ` Linus Torvalds
2016-05-21  0:48               ` Davidlohr Bueso
2016-05-21  2:30                 ` Linus Torvalds
2016-05-21  7:37                 ` Peter Zijlstra
2016-05-21 13:49                   ` Manfred Spraul
2016-05-24 10:57                     ` Peter Zijlstra
2016-05-21 17:14                   ` Davidlohr Bueso
2016-05-23 12:25           ` Peter Zijlstra
2016-05-23 17:52             ` Linus Torvalds
2016-05-25  6:37               ` Boqun Feng
2016-05-22  8:43         ` Manfred Spraul
2016-05-22  9:38           ` Peter Zijlstra [this message]
2016-05-20 16:20   ` Davidlohr Bueso
2016-05-20 20:44   ` Waiman Long
2016-05-20 20:53     ` Peter Zijlstra

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