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From: Thomas Gleixner <tglx@linutronix.de>
To: Junaid Shahid <junaids@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	linux-kernel@vger.kernel.org,
	Andres Lagar-Cavilla <andreslc@google.com>,
	Greg Thelen <gthelen@google.com>,
	Rusty Russell <rusty@rustcorp.com.au>
Subject: Re: [PATCH] kthread: Fix race condition between kthread_parkme() and kthread_unpark()
Date: Fri, 29 Sep 2017 09:59:55 +0200 (CEST)	[thread overview]
Message-ID: <alpine.DEB.2.20.1709290958450.1890@nanos> (raw)
In-Reply-To: <CAL-GctE0BLVk=ps09dnir8pcpnfzg88jMK4CKkRVmY7-ho87nQ@mail.gmail.com>

On Thu, 28 Sep 2017, Junaid Shahid wrote:

> Hi Peter,
> 
> It looks like try_cmpxchg is not available on non-x86 archs, but other than
> that the version that you proposed looks good.
> 
> One thing that I am a bit curious about is that the original code, before
> either patch, had a test_and_set_bit for KTHREAD_IS_PARKED rather than just
> a set_bit. I can't think of any reason why that was needed, since it
> doesn't look like TASK_PARKED tasks are susceptible to spurious wakeups. Do
> you by any chance happen to know if there was any specific reason for it?

Everything is susceptible to spurious wakeups and has to deal with it.

Thanks,

	tglx

  parent reply	other threads:[~2017-09-29  8:00 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-29  2:32 Junaid Shahid
2017-05-30 22:37 ` Junaid Shahid
2017-05-30 22:40   ` Andrew Morton
2017-07-18  0:13     ` Junaid Shahid
2017-07-18  6:35       ` Thomas Gleixner
2017-09-27 12:17 ` Peter Zijlstra
     [not found]   ` <CAL-GctE0BLVk=ps09dnir8pcpnfzg88jMK4CKkRVmY7-ho87nQ@mail.gmail.com>
2017-09-29  7:59     ` Thomas Gleixner [this message]
2017-09-29  8:28       ` Peter Zijlstra
2017-09-29 20:58         ` Junaid Shahid

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