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Date: Fri, 20 Mar 2015 13:54:09 -0600
From: David Ahern <david.ahern@oracle.com>
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To: David Miller <davem@davemloft.net>
CC: torvalds@linux-foundation.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org
Subject: Re: 4.0.0-rc4: panic in free_block
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On 3/20/15 1:47 PM, David Miller wrote:
> From: David Ahern <david.ahern@oracle.com>
> Date: Fri, 20 Mar 2015 12:05:05 -0600
>
>> DaveM: do you mind if I submit a patch to change the default for sparc
>> to SLUB?
>
> I think we're jumping the gun about all of this, and doing anything
> with default Kconfig settings would be entirely premature until we
> know what the real bug is.

The suggestion to change to SLUB as the default was based on Linus' 
comment "SLAB is probably also almost unheard of in high-CPU
configurations, since slub has all the magical unlocked lists etc for
scalability."

>
> On my T4-2 I've used nothing but SLAB and haven't hit any of these
> problems.  I can't even remember the last time I turned SLUB on,
> and it's just because I'm lazy.
>

Interesting. With -j <64 and talking softly it completes. But -j 128 and 
higher always ends in a panic.