On 10/14/19 3:22 PM, Thomas Hellström (VMware) wrote: > From: Thomas Hellström <thellstrom@xxxxxxxxxx> > > Graphics APIs like OpenGL 4.4 and Vulkan require the graphics driver > to provide coherent graphics memory, meaning that the GPU sees any > content written to the coherent memory on the next GPU operation that > touches that memory, and the CPU sees any content written by the GPU > to that memory immediately after any fence object trailing the GPU > operation is signaled. > > Paravirtual drivers that otherwise require explicit synchronization > needs to do this by hooking up dirty tracking to pagefault handlers > and buffer object validation. > > Provide mm helpers needed for this and that also allow for huge pmd- > and pud entries (patch 1-3), and the associated vmwgfx code (patch 4-7). > > The code has been tested and exercised by a tailored version of mesa > where we disable all explicit synchronization and assume graphics memory > is coherent. The performance loss varies of course; a typical number is > around 5%. > > I would like to merge this code through the DRM tree, so an ack to include > the new mm helpers in that merge would be greatly appreciated. > > Changes since RFC: > - Merge conflict changes moved to the correct patch. Fixes intra-patchset > compile errors. > - Be more aggressive when turning ttm vm code into helpers. This makes sure > we can use a const qualifier on the vmwgfx vm_ops. > - Reinstate a lost comment an fix an error path that was broken when turning > the ttm vm code into helpers. > - Remove explicit type-casts of struct vm_area_struct::vm_private_data > - Clarify the locking inversion that makes us not being able to use the mm > pagewalk code. > > Changes since v1: > - Removed the vmwgfx maintainer entry for as_dirty_helpers.c, updated > commit message accordingly > - Removed the TTM patches from the series as they are merged separately > through DRM. > Changes since v2: > - Split out the pagewalk code from as_dirty_helpers.c and document locking. > - Add pre_vma and post_vma callbacks to the pagewalk code. > - Remove huge pmd and -pud asserts that would trip when we protect vmas with > struct address_space::i_mmap_rwsem rather than with > struct vm_area_struct::mmap_sem. > - Do some naming cleanup in as_dirty_helpers.c > Changes since v3: > - Extensive renaming of the dirty helpers including the filename. > - Update walk_page_mapping() doc. > - Update the pagewalk code to not unconditionally split pmds if a pte_entry() > callback is present. Update the dirty helper pmd_entry accordingly. > - Use separate walk ops for the dirty helpers. > - Update the pagewalk code to take the pagetable lock in walk_pte_range. > Changes since v4: > - Fix pte pointer confusion in patch 2/8 > - Skip the pagewalk code conditional split patch for now, and update the > mapping_dirty_helper accordingly. That problem will be solved in a cleaner > way in a follow-up patchset. > Changes since v5: > - Fix tlb flushing when we have other pending tlb flushes. > > Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> > Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> > Cc: Will Deacon <will.deacon@xxxxxxx> > Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> > Cc: Rik van Riel <riel@xxxxxxxxxxx> > Cc: Minchan Kim <minchan@xxxxxxxxxx> > Cc: Michal Hocko <mhocko@xxxxxxxx> > Cc: Huang Ying <ying.huang@xxxxxxxxx> > Cc: Jérôme Glisse <jglisse@xxxxxxxxxx> > Cc: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> > Kirill, Linus I have a formal Ack for two of the four mm patches. Is there a chance I can get an ack to merge the mm patches of this series through drm with the vmwgfx patches? Thanks, Thomas
