Invoke folio_mark_accessed() in mmap page faults to add the folio to the memory manager's LRU list. Userspace invokes mmap to get the memory for software rendering. Compositors do the same when creating the final on-screen image, so keeping the pages in LRU makes sense. Avoids paging out graphics buffers when under memory pressure.
In page_mkwrite, further invoke the folio_mark_dirty() to add the folio for writeback, should the underlying file be paged out from system memory. This rarely happens in practice, yet it would corrupt the buffer content. This has little effect on a system's hardware-accelerated rendering, which only mmaps for an initial setup of textures, meshes, shaders, etc. v2: - adapt to changes in drm_gem_shmem_try_mmap_pmd() Signed-off-by: Thomas Zimmermann <[email protected]> Reviewed-by: Boris Brezillon <[email protected]> --- drivers/gpu/drm/drm_gem_shmem_helper.c | 20 +++++++++++++++++++- 1 file changed, 19 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_gem_shmem_helper.c b/drivers/gpu/drm/drm_gem_shmem_helper.c index 24553dec070d..c2ee30967c41 100644 --- a/drivers/gpu/drm/drm_gem_shmem_helper.c +++ b/drivers/gpu/drm/drm_gem_shmem_helper.c @@ -597,12 +597,17 @@ static vm_fault_t drm_gem_shmem_fault(struct vm_fault *vmf) } ret = drm_gem_shmem_try_map_pmd(vmf, vmf->address, page); - if (ret != VM_FAULT_NOPAGE) { + if (ret == VM_FAULT_NOPAGE) { + struct folio *folio = page_folio(page); + + folio_mark_accessed(folio); + } else { struct folio *folio = page_folio(page); get_page(page); folio_lock(folio); + folio_mark_accessed(folio); vmf->page = page; ret = VM_FAULT_LOCKED; @@ -648,10 +653,23 @@ static void drm_gem_shmem_vm_close(struct vm_area_struct *vma) drm_gem_vm_close(vma); } +static vm_fault_t drm_gem_shmem_page_mkwrite(struct vm_fault *vmf) +{ + struct folio *folio = page_folio(vmf->page); + + file_update_time(vmf->vma->vm_file); + + folio_lock(folio); + folio_mark_dirty(folio); + + return VM_FAULT_LOCKED; +} + const struct vm_operations_struct drm_gem_shmem_vm_ops = { .fault = drm_gem_shmem_fault, .open = drm_gem_shmem_vm_open, .close = drm_gem_shmem_vm_close, + .page_mkwrite = drm_gem_shmem_page_mkwrite, }; EXPORT_SYMBOL_GPL(drm_gem_shmem_vm_ops); -- 2.52.0
