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Date:   Wed, 30 May 2018 11:11:19 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Huaisheng HS1 Ye <yehs1@lenovo.com>
Cc:     Michal Hocko <mhocko@kernel.org>,
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Subject: Re: [External]  Re: [RFC PATCH v2 00/12] get rid of
        GFP_ZONE_TABLE/BAD
Message-ID: <20180530091119.GA30154@lst.de>
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On Wed, May 30, 2018 at 09:02:13AM +0000, Huaisheng HS1 Ye wrote:
> 
> I don't quite understand that. I think those, mostly drivers, need to
> get the correct zone they want. ZONE_DMA32 is an example, if drivers can be
> satisfied with a low mem zone, why they mark the gfp flags as
> 'GFP_KERNEL|__GFP_DMA32'?

Drivers should never use GFP_DMA32 directly.  The right abstraction is
the DMA API, ZONE_DMA32 is just a helper.