Am 31.07.2018 um 10:58 schrieb Zhang, Jerry (Junwei): > On 07/31/2018 04:13 PM, Christian König wrote: >> Am 31.07.2018 um 10:05 schrieb Zhang, Jerry (Junwei): >>> On 07/31/2018 03:03 PM, Christian König wrote: >>>> Am 31.07.2018 um 08:58 schrieb Zhang, Jerry (Junwei): >>>>> On 07/30/2018 06:47 PM, Christian König wrote: >>>>>> Am 30.07.2018 um 12:02 schrieb Junwei Zhang: >>>>>> [SNIP] >>>>>> Please double check if that is still up to date. >>>>> >>>>> We may have to replace drm_gem_object_reference() with >>>>> drm_gem_object_get(). >>>>> >>>>> On 2nd thought, do we really need to do reference every time? >>>> >>>> Yes, that's a must have. Otherwise the handle could be freed and >>>> reused already when we return. >>>> >>>>> if UMD find the same gem object for 3 times, it also need to >>>>> explicitly free(put) that object for 3 times? >>>> >>>> Correct yes. Thinking more about this the real problem is to >>>> translate the handle into a structure in libdrm. >>>> >>>> Here we are back to the problem Marek and Michel has been working >>>> on for a while that we always need to be able to translate a handle >>>> into a bo structure..... >>>> >>>> So that needs to be solved before we can upstream the changes. >>> >>> Thanks for your info. >>> It's better to fix that before upstream. >> >> Thinking more about this the hash currently used in libdrm is not >> adequate any more. >> >> E.g. we now need to be able to find all BOs based on their handle. >> Since the handles are dense either an r/b tree or a radix tree now >> sounds like the best approach to me. > > Not sure the exact reason that we added hash table in libdrm. The reason for that was that when a kernel function returns a handle we need to make sure that we always use the same struct amdgpu_bo for it. Otherwise you run into quite some problems with syncing etc... > But it really costs much less time than calling IOCTL to find BO by > their handles. Well we could just completely drop the kernel implementation and use an userspace implementation. And yes I agree when we need a tree anyway it would probably be faster than calling the IOCTL to find the BO. Christian. > > In this case, UMD seems not to be able to get BO handle and try to > verify it by cpu address then. > In another word, UMD would like to find if the memory is created as BO > or system memory, I suppose. > > Regards, > Jerry > > >> >> Christian. >> >>> >>> Regards, >>> Jerry >> > _______________________________________________ > amd-gfx mailing list > amd-gfx at lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/amd-gfx
