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Date:   Fri, 8 Mar 2019 08:28:20 -0700
From:   Tycho Andersen <tycho@tycho.ws>
To:     "Tobin C. Harding" <tobin@kernel.org>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Christopher Lameter <cl@linux.com>,
        Pekka Enberg <penberg@cs.helsinki.fi>,
        Matthew Wilcox <willy@infradead.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [RFC 02/15] slub: Add isolate() and migrate() methods
Message-ID: <20190308152820.GB373@cisco>
References: <20190308041426.16654-1-tobin@kernel.org>
 <20190308041426.16654-3-tobin@kernel.org>
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On Fri, Mar 08, 2019 at 03:14:13PM +1100, Tobin C. Harding wrote:
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index f9d89c1b5977..754acdb292e4 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -298,6 +298,10 @@ int slab_unmergeable(struct kmem_cache *s)
>  	if (!is_root_cache(s))
>  		return 1;
>  
> +	/*
> +	 * s->isolate and s->migrate imply s->ctor so no need to
> +	 * check them explicitly.
> +	 */

Shouldn't this implication go the other way, i.e.
    s->ctor => s->isolate & s->migrate
?

>  	if (s->ctor)
>  		return 1;

Tycho