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Date:   Thu, 11 Aug 2022 09:43:46 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Michal Hocko <mhocko@suse.com>
Cc:     Baoquan He <bhe@redhat.com>, Christoph Hellwig <hch@lst.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        John Donnelly <john.p.donnelly@oracle.com>,
        David Hildenbrand <david@redhat.com>, linux-mm@kvack.org,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] dma/pool: do not complain if DMA pool is not allocated
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References: <20220325122559.14251-1-mhocko@kernel.org> <Yj28gjonUa9+0yae@dhcp22.suse.cz> <20220325164856.GA16800@lst.de> <Yj3zyLs4f+ba6UqF@dhcp22.suse.cz> <YupFSpXOrcfXJNya@dhcp22.suse.cz> <YuqNToCACD8kKBG+@MiWiFi-R3L-srv> <YuqOrJKcgfamdXkk@dhcp22.suse.cz> <YuqU87SDwP0zg+c7@MiWiFi-R3L-srv> <YuqX0OAItlMDfRUV@dhcp22.suse.cz>
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On Wed, Aug 03, 2022 at 05:44:16PM +0200, Michal Hocko wrote:
> Unfortunately generic kernels cannot really know there is any
> crippled device without some code to some checking early boot (and I am
> not even sure this would be sufficient).

But we can know if we need the pool, which is only when AMD SEV is
enabled.  So we could add a check and skip allocating all the pools
including the GFP_DMA32 and GFP_KERNEL ones.  I can look into that.