From: Christoph Hellwig <hch@infradead.org>
To: "Andrew F. Davis" <afd@ti.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Laura Abbott <labbott@redhat.com>,
John Stultz <john.stultz@linaro.org>,
lkml <linux-kernel@vger.kernel.org>,
Benjamin Gaignard <benjamin.gaignard@linaro.org>,
Sumit Semwal <sumit.semwal@linaro.org>,
Liam Mark <lmark@codeaurora.org>,
Pratik Patel <pratikp@codeaurora.org>,
Brian Starkey <Brian.Starkey@arm.com>,
Vincent Donnefort <Vincent.Donnefort@arm.com>,
Sudipto Paul <Sudipto.Paul@arm.com>,
Xu YiPing <xuyiping@hisilicon.com>,
"Chenfeng (puck)" <puck.chen@hisilicon.com>,
butao <butao@hisilicon.com>,
"Xiaqing (A)" <saberlily.xia@hisilicon.com>,
Yudongbin <yudongbin@hisilicon.com>,
Chenbo Feng <fengc@google.com>,
Alistair Strachan <astrachan@google.com>,
dri-devel <dri-devel@lists.freedesktop.org>
Subject: Re: [PATCH v6 4/5] dma-buf: heaps: Add CMA heap to dmabuf heaps
Date: Thu, 25 Jul 2019 07:05:48 -0700 [thread overview]
Message-ID: <20190725140548.GB25010@infradead.org> (raw)
In-Reply-To: <18975c1a-7e4e-fab3-eec8-387fbf9dcfe5@ti.com>
On Thu, Jul 25, 2019 at 09:47:11AM -0400, Andrew F. Davis wrote:
> This is a central allocator, it is not tied to any one device. If we
> knew the one device ahead of time we would just use the existing dma_alloc.
>
> We might be able to solve some of that with late mapping after all the
> devices attach to the buffer, but even then, which device's CMA area
> would we chose to use from all the attached devices?
>
> I can agree that allocating from per-device CMA using Heaps doesn't make
> much sense, but for global pools I'm not sure I see any way to allow
> devices to select which pool is right for a specific use. They don't
> have the full use-case information like the application does, the
> selection needs to be made from the application.
Well, the examples we had before was that we clear want to use the
per-device CMA area. And at least in upstream a CMA area either is
global or attached to a device, as we otherwise wouldn't find it.
next prev parent reply other threads:[~2019-07-25 14:05 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-24 19:49 [PATCH v6 0/5] DMA-BUF Heaps (destaging ION) John Stultz
2019-06-24 19:49 ` [PATCH v6 1/5] dma-buf: Add dma-buf heaps framework John Stultz
2019-06-24 19:49 ` [PATCH v6 2/5] dma-buf: heaps: Add heap helpers John Stultz
2019-06-24 19:49 ` John Stultz
2019-07-18 10:06 ` Christoph Hellwig
2019-07-23 4:09 ` John Stultz
2019-07-23 4:09 ` John Stultz
2019-07-23 20:09 ` Rob Clark
2019-07-23 20:09 ` Rob Clark
2019-07-24 6:55 ` Christoph Hellwig
2019-07-24 6:55 ` Christoph Hellwig
2019-07-24 15:20 ` Andrew F. Davis
2019-07-24 15:20 ` Andrew F. Davis
2019-07-25 12:41 ` Christoph Hellwig
2019-07-25 12:41 ` Christoph Hellwig
2019-07-25 15:23 ` Rob Clark
2019-07-25 15:23 ` Rob Clark
2019-07-24 6:58 ` Christoph Hellwig
2019-07-24 6:58 ` Christoph Hellwig
2019-06-24 19:49 ` [PATCH v6 3/5] dma-buf: heaps: Add system heap to dmabuf heaps John Stultz
2019-06-24 19:49 ` [PATCH v6 4/5] dma-buf: heaps: Add CMA " John Stultz
2019-07-18 10:08 ` Christoph Hellwig
2019-07-23 5:04 ` John Stultz
2019-07-23 5:04 ` John Stultz
2019-07-24 6:59 ` Christoph Hellwig
2019-07-24 8:08 ` Benjamin Gaignard
2019-07-25 12:45 ` Christoph Hellwig
2019-07-24 11:38 ` Laura Abbott
2019-07-25 12:48 ` Christoph Hellwig
2019-07-25 13:47 ` Andrew F. Davis
2019-07-25 13:47 ` Andrew F. Davis
2019-07-25 14:05 ` Christoph Hellwig [this message]
2019-07-24 15:46 ` Andrew F. Davis
2019-07-25 12:50 ` Christoph Hellwig
2019-07-25 13:31 ` Andrew F. Davis
2019-07-25 13:31 ` Andrew F. Davis
2019-07-25 14:04 ` Christoph Hellwig
2019-07-25 14:10 ` Andrew F. Davis
2019-07-25 14:11 ` Christoph Hellwig
2019-07-25 14:25 ` Andrew F. Davis
2019-07-25 14:30 ` Christoph Hellwig
2019-07-25 14:51 ` Andrew F. Davis
2019-07-25 14:51 ` Andrew F. Davis
2019-07-24 18:46 ` John Stultz
2019-07-24 18:46 ` John Stultz
2019-07-25 12:52 ` Christoph Hellwig
2019-07-25 13:20 ` Benjamin Gaignard
2019-07-25 14:33 ` Christoph Hellwig
2019-07-25 14:46 ` Benjamin Gaignard
2019-06-24 19:49 ` [PATCH v6 5/5] kselftests: Add dma-heap test John Stultz
2019-06-24 19:49 ` John Stultz
2019-07-01 21:45 ` [PATCH v6 0/5] DMA-BUF Heaps (destaging ION) Laura Abbott
2019-07-01 21:55 ` John Stultz
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