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Date:   Tue, 10 Apr 2018 12:30:23 -0500 (CDT)
From:   Christopher Lameter <cl@linux.com>
To:     Matthew Wilcox <willy@infradead.org>
cc:     Eric Dumazet <eric.dumazet@gmail.com>, linux-mm@kvack.org,
        Matthew Wilcox <mawilcox@microsoft.com>,
        Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org, Jan Kara <jack@suse.cz>,
        Jeff Layton <jlayton@redhat.com>,
        Mel Gorman <mgorman@techsingularity.net>,
        stable@vger.kernel.org
Subject: Re: [PATCH 1/2] slab: __GFP_ZERO is incompatible with a
 constructor
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On Tue, 10 Apr 2018, Matthew Wilcox wrote:

> If we want to get rid of the concept of constructors, it's doable,
> but somebody needs to do the work to show what the effects will be.

How do you envision dealing with the SLAB_TYPESAFE_BY_RCU slab caches?
Those must have a defined state of the objects at all times and a constructor is
required for that. And their use of RCU is required for numerous lockless
lookup algorithms in the kernhel.