Message-ID: <dc648afe-6dbe-55c9-ebf6-9334d71706b4@oracle.com>
Date:   Tue, 14 Dec 2021 11:07:34 -0600
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Subject: Re: [PATCH v3 5/5] mm/slub: do not create dma-kmalloc if no managed
 pages in DMA zone
Content-Language: en-US
To:     Christoph Hellwig <hch@lst.de>, Baoquan He <bhe@redhat.com>
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        akpm@linux-foundation.org, cl@linux.com, kexec@lists.infradead.org,
        stable@vger.kernel.org, Pekka Enberg <penberg@kernel.org>,
        David Rientjes <rientjes@google.com>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Vlastimil Babka <vbabka@suse.cz>
References: <20211213122712.23805-1-bhe@redhat.com>
 <20211213122712.23805-6-bhe@redhat.com> <20211214163124.GA21762@lst.de>
From:   john.p.donnelly@oracle.com
In-Reply-To: <20211214163124.GA21762@lst.de>
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On 12/14/21 10:31 AM, Christoph Hellwig wrote:
> On Mon, Dec 13, 2021 at 08:27:12PM +0800, Baoquan He wrote:
>> Dma-kmalloc will be created as long as CONFIG_ZONE_DMA is enabled.
>> However, it will fail if DMA zone has no managed pages. The failure
>> can be seen in kdump kernel of x86_64 as below:
> 
> Please just switch the sr allocation to use GFP_KERNEL without GFP_DMA.
> The block layer will do the proper bounce buffering underneath for the
> very unlikely case that we're actually using the single HBA driver that
> has ISA DMA addressing limitations.
> 
> Same for the ch drive, btw.

Hi,

Is CONFIG_ZONE_DMA even needed anymore in x86_64  ?