From: Hyesoo Yu <hyesoo.yu@samsung.com>
To: Minchan Kim <minchan@kernel.org>
Cc: John Stultz <john.stultz@linaro.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
david@redhat.com, Michal Hocko <mhocko@suse.com>,
Suren Baghdasaryan <surenb@google.com>,
KyongHo Cho <pullip.cho@samsung.com>,
John Dias <joaodias@google.com>,
Hridya Valsaraju <hridya@google.com>,
Sumit Semwal <sumit.semwal@linaro.org>,
linux-media <linux-media@vger.kernel.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
Christoph Hellwig <hch@infradead.org>,
Rob Herring <robh+dt@kernel.org>,
"moderated list:DMA BUFFER SHARING FRAMEWORK"
<linaro-mm-sig@lists.linaro.org>
Subject: Re: [PATCH v3 4/4] dma-buf: heaps: add chunk heap to dmabuf heaps
Date: Wed, 20 Jan 2021 12:32:08 +0900 [thread overview]
Message-ID: <20210120033208.GA179511@KEI> (raw)
In-Reply-To: <YAdC2J4x/4J9ozkq@google.com>
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On Tue, Jan 19, 2021 at 12:36:40PM -0800, Minchan Kim wrote:
> On Tue, Jan 19, 2021 at 10:29:29AM -0800, John Stultz wrote:
> > On Tue, Jan 12, 2021 at 5:22 PM Minchan Kim <minchan@kernel.org> wrote:
> > >
> > > From: Hyesoo Yu <hyesoo.yu@samsung.com>
> > >
> > > This patch supports chunk heap that allocates the buffers that
> > > arranged into a list a fixed size chunks taken from CMA.
> > >
> > > The chunk heap driver is bound directly to a reserved_memory
> > > node by following Rob Herring's suggestion in [1].
> > >
> > > [1] https://lore.kernel.org/lkml/20191025225009.50305-2-john.stultz@linaro.org/T/#m3dc63acd33fea269a584f43bb799a876f0b2b45d
> > >
> > > Signed-off-by: Hyesoo Yu <hyesoo.yu@samsung.com>
> > > Signed-off-by: Hridya Valsaraju <hridya@google.com>
> > > Signed-off-by: Minchan Kim <minchan@kernel.org>
> > > ---
> > ...
> > > +static int register_chunk_heap(struct chunk_heap *chunk_heap_info)
> > > +{
> > > + struct dma_heap_export_info exp_info;
> > > +
> > > + exp_info.name = cma_get_name(chunk_heap_info->cma);
> >
> > One potential issue here, you're setting the name to the same as the
> > CMA name. Since the CMA heap uses the CMA name, if one chunk was
> > registered as a chunk heap but also was the default CMA area, it might
> > be registered twice. But since both would have the same name it would
> > be an initialization race as to which one "wins".
>
> Good point. Maybe someone might want to use default CMA area for
> both cma_heap and chunk_heap. I cannot come up with ideas why we
> should prohibit it atm.
>
> >
> > So maybe could you postfix the CMA name with "-chunk" or something?
>
> Hyesoo, Any opinion?
> Unless you have something other idea, let's fix it in next version.
>
I agree that. It is not good to use heap name directly as cma name.
Let's postfix the name with '-chunk'
Thanks,
Regards.
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next prev parent reply other threads:[~2021-01-20 3:40 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-13 1:21 [PATCH v3 0/4] Chunk Heap Support on DMA-HEAP Minchan Kim
2021-01-13 1:21 ` [PATCH v3 1/4] mm: cma: introduce gfp flag in cma_alloc instead of no_warn Minchan Kim
2021-01-20 21:08 ` Suren Baghdasaryan
2021-01-13 1:21 ` [PATCH v3 2/4] mm: failfast mode with __GFP_NORETRY in alloc_contig_range Minchan Kim
2021-01-13 8:39 ` David Hildenbrand
2021-01-14 18:04 ` Minchan Kim
2021-01-13 1:21 ` [PATCH v3 3/4] dt-bindings: reserved-memory: Make DMA-BUF CMA heap DT-configurable Minchan Kim
2021-01-13 15:45 ` Rob Herring
2021-01-13 17:30 ` Hridya Valsaraju
2021-01-14 14:01 ` Rob Herring
2021-01-14 19:49 ` Hridya Valsaraju
2021-01-13 1:21 ` [PATCH v3 4/4] dma-buf: heaps: add chunk heap to dmabuf heaps Minchan Kim
2021-01-13 3:38 ` Randy Dunlap
2021-01-14 1:04 ` Minchan Kim
2021-01-19 15:51 ` Minchan Kim
2021-01-19 18:29 ` John Stultz
2021-01-19 20:36 ` Minchan Kim
2021-01-20 3:32 ` Hyesoo Yu [this message]
2021-01-20 20:53 ` Suren Baghdasaryan
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