Am 21.08.19 um 16:47 schrieb Daniel Vetter: > On Wed, Aug 21, 2019 at 4:27 PM Thomas Hellström (VMware) > <thomas_os@xxxxxxxxxxxx> wrote: >> On 8/21/19 4:09 PM, Daniel Vetter wrote: >>> On Wed, Aug 21, 2019 at 2:47 PM Thomas Hellström (VMware) >>> <thomas_os@xxxxxxxxxxxx> wrote: >>>> On 8/21/19 2:40 PM, Thomas Hellström (VMware) wrote: >>>>> On 8/20/19 4:53 PM, Daniel Vetter wrote: >>>>> [SNIP] >> but to keep the mm latency optimization using the RETRY functionality: > Still no idea why this is needed? All the comments here and the code > and history seem like they've been about the mmap_sem vs dma_resv > inversion between driver ioctls and fault handling here. Once that's > officially fixed there's no reason to play games here and retry loops > - previously that was necessary because the old ttm_bo_vm_fault had a > busy spin and that's definitely not nice. If it's needed I think it > should be a second patch on top, to keep this all clear. I had to > audit an enormous amount of code, I'd like to make sure I didn't miss > anything before we start to make this super fancy again. Further > patches on top is obviously all fine with me. I think this is just an optimization to not hold the mmap_sem while waiting for the dma_resv lock. I agree that it shouldn't be necessary, but maybe it's a good idea for performance. I'm also OK with removing it, cause I'm not sure if it's worth it. But Thomas noted correctly that we should probably do it in a separate patch so that when somebody points out "Hey my system is slower now!" he's able to bisect to the change. Christian. > -Daniel > >> Thanks, >> Thomas >> _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
