From: John Stultz <john.stultz@linaro.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Alistair Strachan <astrachan@google.com>,
Greg KH <gregkh@linuxfoundation.org>,
Chenbo Feng <fengc@google.com>,
lkml <linux-kernel@vger.kernel.org>,
Liam Mark <lmark@codeaurora.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
"Andrew F . Davis" <afd@ti.com>
Subject: Re: [RFC][PATCH 4/5 v2] dma-buf: heaps: Add CMA heap to dmabuf heapss
Date: Fri, 15 Mar 2019 13:08:38 -0700 [thread overview]
Message-ID: <CALAqxLVc475=eFSpJmYUE_82LWyR+bt1vWr-_0aGN=GPicPKVA@mail.gmail.com> (raw)
In-Reply-To: <20190315090652.GE4470@infradead.org>
On Fri, Mar 15, 2019 at 2:06 AM Christoph Hellwig <hch@infradead.org> wrote:
>
> On Tue, Mar 05, 2019 at 12:54:32PM -0800, John Stultz wrote:
> > This adds a CMA heap, which allows userspace to allocate
> > a dma-buf of contiguous memory out of a CMA region.
>
> With my previous suggestion of DMA API usage you'd get CMA support for
> free in the system one instead of all this duplicate code..
Hey Christoph! Thanks for the review here! I'm still digesting your
comments, so apologies if I misunderstand.
On the point here, unless you're referring to some earlier suggestion
on a previous discussion (and not the system heap feedback), part of
the reason there are separate heaps is to allow Android to be able to
optimize where the allocations are coming from to best match the use
case. So they only want to allocate CMA backed dmabufs when the use
case has devices that require it, or they may even want to have
separate a CMA region reserved for a specific use case (like camera
buffers). Similarly for any future heap for allocating secure
dma-bufs. So while in the implementation we can consolidate the code
more, but we'd still probably want to have separate heaps.
Does that make sense? Am I misinterpreting your feedback?
thanks
-john
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next prev parent reply other threads:[~2019-03-15 20:08 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-05 20:54 [RFC][PATCH 0/5 v2] DMA-BUF Heaps (destaging ION) John Stultz
2019-03-05 20:54 ` [RFC][PATCH 1/5 v2] dma-buf: Add dma-buf heaps framework John Stultz
2019-03-06 16:12 ` Benjamin Gaignard
2019-03-06 16:57 ` John Stultz
2019-03-15 8:55 ` Christoph Hellwig
2019-03-06 16:27 ` Andrew F. Davis
2019-03-06 19:03 ` John Stultz
2019-03-06 21:45 ` Andrew F. Davis
2019-03-15 8:54 ` Christoph Hellwig
2019-03-15 20:24 ` Andrew F. Davis
2019-03-15 20:18 ` Laura Abbott
2019-03-15 20:49 ` Andrew F. Davis
2019-03-15 21:29 ` John Stultz
2019-03-15 22:44 ` Laura Abbott
2019-03-18 4:38 ` Sumit Semwal
2019-03-18 4:41 ` Sumit Semwal
2019-03-19 12:08 ` Brian Starkey
2019-03-19 15:24 ` Andrew F. Davis
2019-03-21 21:16 ` John Stultz
2019-03-27 14:53 ` Greg KH
2019-03-28 6:09 ` John Stultz
2019-03-05 20:54 ` [RFC][PATCH 2/5 v2] dma-buf: heaps: Add heap helpers John Stultz
2019-03-13 20:18 ` Liam Mark
2019-03-13 21:48 ` Andrew F. Davis
2019-03-13 22:57 ` Liam Mark
2019-03-13 23:42 ` Andrew F. Davis
2019-03-15 9:06 ` Christoph Hellwig
2019-03-19 15:03 ` Andrew F. Davis
2019-03-21 20:01 ` John Stultz
2019-03-19 14:26 ` Brian Starkey
2019-03-21 20:11 ` John Stultz
2019-03-21 20:35 ` Andrew F. Davis
2019-03-21 20:43 ` Andrew F. Davis
2019-03-05 20:54 ` [RFC][PATCH 3/5 v2] dma-buf: heaps: Add system heap to dmabuf heaps John Stultz
2019-03-06 16:01 ` Benjamin Gaignard
2019-03-11 5:48 ` John Stultz
2019-03-13 20:20 ` Liam Mark
2019-03-13 22:49 ` John Stultz
2019-03-15 9:06 ` Christoph Hellwig
2019-03-05 20:54 ` [RFC][PATCH 4/5 v2] dma-buf: heaps: Add CMA heap to dmabuf heapss John Stultz
2019-03-06 16:05 ` Benjamin Gaignard
2019-03-21 20:15 ` John Stultz
2019-03-15 9:06 ` Christoph Hellwig
2019-03-15 20:08 ` John Stultz [this message]
2019-03-19 14:53 ` Brian Starkey
2019-03-05 20:54 ` [RFC][PATCH 5/5 v2] kselftests: Add dma-heap test John Stultz
2019-03-06 16:14 ` Benjamin Gaignard
2019-03-06 16:35 ` Andrew F. Davis
2019-03-06 18:19 ` John Stultz
2019-03-06 18:32 ` Andrew F. Davis
2019-03-06 17:01 ` John Stultz
2019-03-15 20:07 ` Laura Abbott
2019-03-15 20:13 ` John Stultz
2019-03-15 20:49 ` Laura Abbott
2019-03-13 20:23 ` Liam Mark
2019-03-13 20:11 ` [RFC][PATCH 0/5 v2] DMA-BUF Heaps (destaging ION) Liam Mark
2019-03-13 22:30 ` John Stultz
2019-03-13 23:29 ` Liam Mark
2019-03-19 16:54 ` Benjamin Gaignard
2019-03-19 16:59 ` Andrew F. Davis
2019-03-19 21:58 ` Rob Clark
2019-03-19 22:36 ` John Stultz
2019-03-20 9:16 ` Benjamin Gaignard
2019-03-20 14:44 ` Andrew F. Davis
2019-03-20 15:59 ` Benjamin Gaignard
2019-03-20 16:11 ` John Stultz
2019-03-15 20:34 ` Laura Abbott
2019-03-15 23:15 ` Jerome Glisse
2019-03-16 0:16 ` John Stultz
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