> -----Original Message----- > From: intel-gvt-dev [mailto:intel-gvt-dev-bounces@xxxxxxxxxxxxxxxxxxxxx] On > Behalf Of Daniel Vetter > Sent: Thursday, June 29, 2017 4:39 PM > To: Gerd Hoffmann <kraxel@xxxxxxxxxx> > Cc: Wang, Zhenyu Z <zhenyu.z.wang@xxxxxxxxx>; intel- > gfx@xxxxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Chen, Xiaoguang > <xiaoguang.chen@xxxxxxxxx>; Zhang, Tina <tina.zhang@xxxxxxxxx>; Alex > Williamson <alex.williamson@xxxxxxxxxx>; Lv, Zhiyuan > <zhiyuan.lv@xxxxxxxxx>; Kirti Wankhede <kwankhede@xxxxxxxxxx>; intel-gvt- > dev@xxxxxxxxxxxxxxxxxxxxx > Subject: Re: [PATCH v9 5/7] vfio: Define vfio based dma-buf > operations > > On Thu, Jun 29, 2017 at 08:41:53AM +0200, Gerd Hoffmann wrote: > > Hi, > > > > > > Does gvt track the live cycle of all dma-bufs it has handed out? > > > > > > The V9 implementation does track the dma-bufs' live cycle. The > > > original idea was that leaving the dma-bufs' live cycle management > > > to user mode. > > > > That is still the case, user space decides which dma-bufs it'll go > > keep cached. But kernel space can see what user space is doing, so > > there is no need to explicitly tell the kernel whenever a cached > > dma-buf exists or not. > > We do the same trick in drm_prime.c, keeping a cache of exported dma-buf > around for re-exporting. Since for prime sharing the use-case is almost always > re-importing as a drm gem buffer again we can then on re-import also tell > userspace whether it already has that buffer in it's userspace buffer manager, > but that's an additional optimization. With plain dma-buf we could achieve the > same by wiring up a real stat() implementation with unique inode numbers (atm > they all share the anon_inode singleton). But thus far no one asked for that. Thanks. I'm going to submit the v10 version of ABI interface. > > btw I'm lost a bit in the discussion (was on vacation), but I think all the concerns > I've noticed with the initial rfc have been raised already, so things look good. I'll > check the next rfc once that shows up. > -Daniel > -- > Daniel Vetter > Software Engineer, Intel Corporation > http://blog.ffwll.ch > _______________________________________________ > intel-gvt-dev mailing list > intel-gvt-dev@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gvt-dev _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
