From: Mike Rapoport <rppt@kernel.org>
To: Michal Hocko <mhocko@suse.com>
Cc: Haifeng Xu <haifeng.xu@shopee.com>,
David Hildenbrand <david@redhat.com>,
akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/mm_init.c: add debug messsge for dma zone
Date: Thu, 8 Jun 2023 13:13:40 +0300 [thread overview]
Message-ID: <20230608101340.GI52412@kernel.org> (raw)
In-Reply-To: <ZIGcyku+DN5IHtwp@dhcp22.suse.cz>
On Thu, Jun 08, 2023 at 11:18:02AM +0200, Michal Hocko wrote:
> On Thu 08-06-23 15:38:48, Haifeng Xu wrote:
> >
> >
> > 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.
>
> I am not really convinced this is worth touching the code TBH.
The only architecture that sets the dma_reserve is x86_64 and it sets it to
the number of reserved pages in DMA zone. There is no way freesize will be
less than dma_reserve.
I'm not sure that in general dma_reserve has some value now, but that's a
completely different story.
> --
> Michal Hocko
> SUSE Labs
--
Sincerely yours,
Mike.
next prev parent reply other threads:[~2023-06-08 10:14 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-07 9:07 [PATCH] mm/mm_init.c: add debug messsge for dma zone Haifeng Xu
2023-06-07 10:16 ` Michal Hocko
2023-06-07 10:22 ` David Hildenbrand
2023-06-08 3:43 ` Haifeng Xu
2023-06-08 7:38 ` Haifeng Xu
2023-06-08 9:18 ` Michal Hocko
2023-06-08 10:13 ` Mike Rapoport [this message]
2023-06-08 10:51 ` Haifeng Xu
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