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From:   Shakeel Butt <shakeelb@google.com>
Date:   Tue, 25 Jun 2019 11:31:04 -0700
Message-ID: <CALvZod6wR7th1JF407-_i9PfbCzAiakU7mD2HBshH+jW9db1bw@mail.gmail.com>
Subject: Re: [PATCH v7 06/10] mm: don't check the dying flag on kmem_cache creation
To:     Roman Gushchin <guro@fb.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Linux MM <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Kernel Team <kernel-team@fb.com>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Waiman Long <longman@redhat.com>
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On Tue, Jun 11, 2019 at 4:18 PM Roman Gushchin <guro@fb.com> wrote:
>
> There is no point in checking the root_cache->memcg_params.dying
> flag on kmem_cache creation path. New allocations shouldn't be
> performed using a dead root kmem_cache,

Yes, it's the user's responsibility to synchronize the kmem cache
destruction and allocations.

> so no new memcg kmem_cache
> creation can be scheduled after the flag is set. And if it was
> scheduled before, flush_memcg_workqueue() will wait for it anyway.
>
> So let's drop this check to simplify the code.
>
> Signed-off-by: Roman Gushchin <guro@fb.com>

Reviewed-by: Shakeel Butt <shakeelb@google.com>