Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Wed, 19 Aug 2020 12:37:13 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     <wuyun.wu@huawei.com>
Cc:     Christoph Lameter <cl@linux.com>,
        Pekka Enberg <penberg@kernel.org>,
        "David Rientjes" <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>, <liu.xiang6@zte.com.cn>,
        "open list:SLAB ALLOCATOR" <linux-mm@kvack.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm/slub: make add_full() condition more explicit
Message-Id: <20200819123713.38a2509a2b7651f14db33e61@linux-foundation.org>
In-Reply-To: <20200811020240.1231-1-wuyun.wu@huawei.com>
References: <20200811020240.1231-1-wuyun.wu@huawei.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Tue, 11 Aug 2020 10:02:36 +0800 <wuyun.wu@huawei.com> wrote:

> From: Abel Wu <wuyun.wu@huawei.com>
> 
> The commit below is incomplete, as it didn't handle the add_full() part.
> commit a4d3f8916c65 ("slub: remove useless kmem_cache_debug() before remove_full()")
> 
> This patch checks for SLAB_STORE_USER instead of kmem_cache_debug(),
> since that should be the only context in which we need the list_lock for
> add_full().
> 

Does this contradict what the comment tells us?

* This also ensures that the scanning of full
* slabs from diagnostic functions will not see
* any frozen slabs.