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From: Kathleen Chang <yt.chang@mediatek.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Matthias Brugger <matthias.bgg@gmail.com>,
	<wsd_upstream@mediatek.com>, <linux-kernel@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-mediatek@lists.infradead.org>
Subject: Re: [PATCH 1/1] sched: panic, when call schedule with preemption disable
Date: Tue, 26 Nov 2019 21:11:30 +0800	[thread overview]
Message-ID: <1574773890.12247.23.camel@mtksdccf07> (raw)
In-Reply-To: <20191121123048.GQ4097@hirez.programming.kicks-ass.net>

On Thu, 2019-11-21 at 13:30 +0100, Peter Zijlstra wrote:
> On Thu, Nov 21, 2019 at 04:13:05PM +0800, YT Chang wrote:
> > When preemption is disable, call schedule() is incorrect behavior.
> > Suggest to panic directly rather than depend on panic_on_warn.
> 
> Why!?


1. Panic directly will easily find the root cause. 

   Call scheduling in atomic affects not only performance but also
system stability. 
    ex: 
      Call scheduling in IRQ will result in IRQ enable after schedule() 

2. A lot of warnings depend on panic_on_warn. It is not practical to
set panic_on_warn=1. 


WARNING: multiple messages have this Message-ID (diff)
From: Kathleen Chang <yt.chang@mediatek.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Matthias Brugger <matthias.bgg@gmail.com>,
	linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org,
	wsd_upstream@mediatek.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/1] sched: panic, when call schedule with preemption disable
Date: Tue, 26 Nov 2019 21:11:30 +0800	[thread overview]
Message-ID: <1574773890.12247.23.camel@mtksdccf07> (raw)
In-Reply-To: <20191121123048.GQ4097@hirez.programming.kicks-ass.net>

On Thu, 2019-11-21 at 13:30 +0100, Peter Zijlstra wrote:
> On Thu, Nov 21, 2019 at 04:13:05PM +0800, YT Chang wrote:
> > When preemption is disable, call schedule() is incorrect behavior.
> > Suggest to panic directly rather than depend on panic_on_warn.
> 
> Why!?


1. Panic directly will easily find the root cause. 

   Call scheduling in atomic affects not only performance but also
system stability. 
    ex: 
      Call scheduling in IRQ will result in IRQ enable after schedule() 

2. A lot of warnings depend on panic_on_warn. It is not practical to
set panic_on_warn=1. 

_______________________________________________
Linux-mediatek mailing list
Linux-mediatek@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-mediatek

WARNING: multiple messages have this Message-ID (diff)
From: Kathleen Chang <yt.chang@mediatek.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Matthias Brugger <matthias.bgg@gmail.com>,
	linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org,
	wsd_upstream@mediatek.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/1] sched: panic, when call schedule with preemption disable
Date: Tue, 26 Nov 2019 21:11:30 +0800	[thread overview]
Message-ID: <1574773890.12247.23.camel@mtksdccf07> (raw)
In-Reply-To: <20191121123048.GQ4097@hirez.programming.kicks-ass.net>

On Thu, 2019-11-21 at 13:30 +0100, Peter Zijlstra wrote:
> On Thu, Nov 21, 2019 at 04:13:05PM +0800, YT Chang wrote:
> > When preemption is disable, call schedule() is incorrect behavior.
> > Suggest to panic directly rather than depend on panic_on_warn.
> 
> Why!?


1. Panic directly will easily find the root cause. 

   Call scheduling in atomic affects not only performance but also
system stability. 
    ex: 
      Call scheduling in IRQ will result in IRQ enable after schedule() 

2. A lot of warnings depend on panic_on_warn. It is not practical to
set panic_on_warn=1. 

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  reply	other threads:[~2019-11-26 13:11 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-11-21  8:13 [PATCH 1/1] sched: panic, when call schedule with preemption disable YT Chang
2019-11-21  8:13 ` YT Chang
2019-11-21  8:13 ` YT Chang
2019-11-21 12:30 ` Peter Zijlstra
2019-11-21 12:30   ` Peter Zijlstra
2019-11-21 12:30   ` Peter Zijlstra
2019-11-26 13:11   ` Kathleen Chang [this message]
2019-11-26 13:11     ` Kathleen Chang
2019-11-26 13:11     ` Kathleen Chang

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