[PATCH] dix/dispatch: DoGetImage: Use a single buffer

[Daniel Stone]

Hi,


On 1 April 2014 05:54, Keith Packard <keithp at keithp.com> wrote:

> Aaron Plattner <aplattner at nvidia.com> writes:
> > Can't the max image size be multiple gigabytes?  That seems a little
> > large to describe as "close" to running out of heap space.
>
> The problem is that we're going to buffer that in memory anyway, down in
> the OS layer. The only alternative is to block down there waiting for
> the client to drain the image data.
>
> So, the chunking in DIX is not helping reduce memory usage, it's just
> making the OS layer shuffle data around a lot.
>

You're correct in bandwidth/transfer terms, but not in terms of peak
simultaneous usage.

OTOH, I don't think it's really worth worrying about too much.  People do
rather adventurous things like 4K on ARM32, which is fine, but anyone who
then does a core GetImage on the whole thing really deserves whatever they
get.

Cheers,
Daniel
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