On Tuesday, February 10, 2009 2:00 pm Eric Anholt wrote: > On Fri, 2009-02-06 at 14:24 -0800, Jesse Barnes wrote: > > On Friday, February 6, 2009 1:35 pm Thomas Hellström wrote: > > > Jesse Barnes wrote: > > > > 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? > > > > > > Yes, an mmap() is always paired with a vm_close(), and the vm_close() > > > also happens in a crash situation. > > > > This one should cover the cases you found. > > - ref at map time will keep the object around so fault shouldn't fail > > - additional threads will take their refs in vm_open/close > > - unmap will unref and remove mmap_offset allowing object to be freed > > sw_finish doesn't mean unmap (note that it doesn't actually unmap). > > If you want to actually unmap, that should be done with munmap.
Yeah, but it does get called at dri_bo_unmap time... I haven't traced the munmap code to see if it would do what we want... if it ends up in vm_close too then it would be fine (ref at gtt ioctl time, unref at vm_close time, as long as there's not a stray vm_open in there). Jesse -- Jesse Barnes, Intel Open Source Technology Center ------------------------------------------------------------------------------ Create and Deploy Rich Internet Apps outside the browser with Adobe(R)AIR(TM) software. With Adobe AIR, Ajax developers can use existing skills and code to build responsive, highly engaging applications that combine the power of local resources and data with the reach of the web. Download the Adobe AIR SDK and Ajax docs to start building applications today-http://p.sf.net/sfu/adobe-com -- _______________________________________________ Dri-devel mailing list Dri-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dri-devel
