Date: Thu, 13 Apr 2017 18:17:09 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        linux-kernel@vger.kernel.org, mingo@kernel.org, jiangshanlai@gmail.com,
        dipankar@in.ibm.com, akpm@linux-foundation.org,
        mathieu.desnoyers@efficios.com, josh@joshtriplett.org,
        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
Subject: Re: [PATCH tip/core/rcu 01/13] mm: Rename SLAB_DESTROY_BY_RCU to
 SLAB_TYPESAFE_BY_RCU
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On Thu, Apr 13, 2017 at 01:06:56PM +0200, Vlastimil Babka wrote:
> 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.

git log -S SLAB_DESTROY_BY_RCU