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Date:   Thu, 8 Jun 2023 15:38:48 +0800
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Subject: Re: [PATCH] mm/mm_init.c: add debug messsge for dma zone
To:     David Hildenbrand <david@redhat.com>,
        Michal Hocko <mhocko@suse.com>
Cc:     rppt@kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
References: <20230607090734.1259-1-haifeng.xu@shopee.com>
 <ZIBY5niJ/7vvwdHC@dhcp22.suse.cz>
 <ccc68b26-0896-2f2d-ba54-038f34e9eaa2@redhat.com>
From:   Haifeng Xu <haifeng.xu@shopee.com>
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On 2023/6/7 18:22, David Hildenbrand wrote:
> On 07.06.23 12:16, Michal Hocko wrote:
>> On Wed 07-06-23 09:07:34, Haifeng Xu wrote:
>>> If freesize is less than dma_reserve, print warning message to report
>>> this case.
>>
>> Why?
> 
> I'd like to second that question, and add
> 
> a) Did you run into that scenario?
> b) What can an admin do in that case with that error messages?

In theory，dma_reserve shouldn't exceed freesize, so the error messages can remind us
to verify whether the configuration of reserved memory is correct.

> 
> If it reveals a buggy situation, maybe a WARN_ON_ONCE() is warranted ... but maybe only if anybody actually ran into that issue.
>