Re: Gem GTT mmaps..
From: Jesse Barnes
Date: Fri Feb 06 2009 - 12:15:31 EST
On Thursday, February 5, 2009 10:37 am Jesse Barnes wrote:
> So if we leave the lookup reference around from the GTT mapping ioctl, that
> would take care of new mappings. And if we added/removed references at VM
> open/close time, we should be covered for fork. But is it ok to add a new
> unref in the finish ioctl for GTT mapped objects? I don't think so,
> because we don't know for sure if the caller was the one that created the
> new fake offset (which would be one way of detecting whether it was GTT
> mapped). Seems like we need a new unmap ioctl? Or we could put the mapping
> ref/unref in libdrm, where it would be tracked on a per-process basis...
Ah but maybe we should just tear down the fake offset at unmap time; then we'd
be able to use it as an existence test for the mapping and get the
refcounting right. The last thing I thought of was whether we'd be ok in a
map_gtt -> crash case. I *think* the vm_close code will deal with that, if
we do a deref there?
Thanks,
--
Jesse Barnes, Intel Open Source Technology Center
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