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From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
To: rientjes@google.com
Cc: kosaki.motohiro@gmail.com, kosaki.motohiro@jp.fujitsu.com,
	akpm@linux-foundation.org, kamezawa.hiroyu@jp.fujitsu.com,
	linux-mm@kvack.org
Subject: Re: [patch] mm, mempolicy: make mempolicies robust against errors
Date: Wed, 07 Mar 2012 11:24:42 -0500	[thread overview]
Message-ID: <4F578BCA.1090706@jp.fujitsu.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1203062253150.1427@chino.kir.corp.google.com>

On 3/7/2012 1:56 AM, David Rientjes wrote:
> On Wed, 7 Mar 2012, KOSAKI Motohiro wrote:
> 
>> So, I strongly suggest to remove CONFIG_BUG=n. It is neglected very long time
>> and
>> much plenty code assume BUG() is not no-op. I don't think we can fix all
>> place.
>>
>> Just one instruction don't hurt code size nor performance.
> 
> It's a different topic, the proposal here is whether an error in 
> mempolicies (either the code or flipped bit) should crash the kernel or 
> not since it's a condition that can easily be recovered from and leave 
> BUG() to errors that actually are fatal.  Crashing the kernel offers no 
> advantage.

Should crash? The code path never reach. thus there is no ideal behavior.
In this case, BUG() is just unreachable annotation. So let's just annotate
unreachable() even though CONFIG_BUG=n.

WARN_ON_ONCE makes code broat and no positive impact.


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  reply	other threads:[~2012-03-07 20:08 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-03-04 21:43 [patch] mm, mempolicy: dummy slab_node return value for bugless kernels David Rientjes
2012-03-06 20:15 ` Rafael Aquini
2012-03-07  0:08 ` Andrew Morton
2012-03-07  0:55   ` Rafael Aquini
2012-03-07  4:25   ` David Rientjes
2012-03-07  4:29     ` [patch] mm, mempolicy: make mempolicies robust against errors David Rientjes
2012-03-07  5:30       ` KOSAKI Motohiro
2012-03-07  5:58         ` David Rientjes
2012-03-07  6:34           ` KOSAKI Motohiro
2012-03-07  6:56             ` David Rientjes
2012-03-07 16:24               ` KOSAKI Motohiro [this message]
2012-03-07 21:06                 ` David Rientjes
2012-03-08 23:51             ` Andrew Morton
2012-04-26 14:58           ` Christoph Lameter
2012-03-07 11:12     ` [patch] mm, mempolicy: dummy slab_node return value for bugless kernels Glauber Costa
2012-03-07 21:04       ` David Rientjes

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