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Subject: Re: [PATCH tip/core/rcu 01/13] mm: Rename SLAB_DESTROY_BY_RCU to
 SLAB_TYPESAFE_BY_RCU
To: Peter Zijlstra <peterz@infradead.org>,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
References: <20170412165441.GA17149@linux.vnet.ibm.com>
 <1492016149-18834-1-git-send-email-paulmck@linux.vnet.ibm.com>
 <20170413091248.xnctlppstkrm6eq5@hirez.programming.kicks-ass.net>
Cc: linux-kernel@vger.kernel.org, mingo@kernel.org, jiangshanlai@gmail.com,
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        tglx@linutronix.de, rostedt@goodmis.org, dhowells@redhat.com,
        edumazet@google.com, fweisbec@gmail.com, oleg@redhat.com,
        bobby.prani@gmail.com, Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>, linux-mm@kvack.org
From: Vlastimil Babka <vbabka@suse.cz>
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Date: Thu, 13 Apr 2017 13:06:56 +0200
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On 04/13/2017 11:12 AM, Peter Zijlstra wrote:
> On Wed, Apr 12, 2017 at 09:55:37AM -0700, Paul E. McKenney wrote:
>> A group of Linux kernel hackers reported chasing a bug that resulted
>> from their assumption that SLAB_DESTROY_BY_RCU provided an existence
>> guarantee, that is, that no block from such a slab would be reallocated
>> during an RCU read-side critical section.  Of course, that is not the
>> case.  Instead, SLAB_DESTROY_BY_RCU only prevents freeing of an entire
>> slab of blocks.
> 
> And that while we wrote a huge honking comment right along with it...
> 
>> [ paulmck: Add "tombstone" comments as requested by Eric Dumazet. ]
> 
> I cannot find any occurrence of "tomb" or "TOMB" in the actual patch,
> confused?

It's the comments such as:

+ * Note that SLAB_TYPESAFE_BY_RCU was originally named SLAB_DESTROY_BY_RCU.

so that people who remember the old name can git grep its fate.

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