[PATCH v5 6/9] drm/vmwgfx: Support huge page faults

Thomas Hellström (VMware)
2020-03-03T10:23:17Z

With vmwgfx dirty-tracking we need a specialized huge_fault
callback. Implement and hook it up.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Acked-by: Christian König <christian.koenig@amd.com>
---
drivers/gpu/drm/vmwgfx/vmwgfx_drv.h | 4 ++
drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c | 74 +++++++++++++++++++++-
drivers/gpu/drm/vmwgfx/vmwgfx_ttm_glue.c | 5 +-
3 files changed, 81 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
index 86b69397d166..bb2757c98f0a 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
@@ -1430,6 +1430,10 @@ void vmw_bo_dirty_unmap(struct vmw_buffer_object *vbo,
pgoff_t start, pgoff_t end);
vm_fault_t vmw_bo_vm_fault(struct vm_fault *vmf);
vm_fault_t vmw_bo_vm_mkwrite(struct vm_fault *vmf);
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+vm_fault_t vmw_bo_vm_huge_fault(struct vm_fault *vmf,
+ enum page_entry_size pe_size);
+#endif

/**
* VMW_DEBUG_KMS - Debug output for kernel mode-setting
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c b/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c
index 17a5dca7b921..cde3e07ebaf7 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c
@@ -473,7 +473,7 @@ vm_fault_t vmw_bo_vm_fault(struct vm_fault *vmf)
* a lot of unnecessary write faults.
*/
if (vbo->dirty && vbo->dirty->method == VMW_BO_DIRTY_MKWRITE)
- prot = vma->vm_page_prot;
+ prot = vm_get_page_prot(vma->vm_flags & ~VM_SHARED);
else
prot = vm_get_page_prot(vma->vm_flags);

@@ -486,3 +486,75 @@ vm_fault_t vmw_bo_vm_fault(struct vm_fault *vmf)

return ret;
}
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+vm_fault_t vmw_bo_vm_huge_fault(struct vm_fault *vmf,
+ enum page_entry_size pe_size)
+{
+ struct vm_area_struct *vma = vmf->vma;
+ struct ttm_buffer_object *bo = (struct ttm_buffer_object *)
+ vma->vm_private_data;
+ struct vmw_buffer_object *vbo =
+ container_of(bo, struct vmw_buffer_object, base);
+ pgprot_t prot;
+ vm_fault_t ret;
+ pgoff_t fault_page_size;
+ bool write = vmf->flags & FAULT_FLAG_WRITE;
+ bool is_cow_mapping =
+ (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE;
+
+ switch (pe_size) {
+ case PE_SIZE_PMD:
+ fault_page_size = HPAGE_PMD_SIZE >> PAGE_SHIFT;
+ break;
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
+ case PE_SIZE_PUD:
+ fault_page_size = HPAGE_PUD_SIZE >> PAGE_SHIFT;
+ break;
+#endif
+ default:
+ WARN_ON_ONCE(1);
+ return VM_FAULT_FALLBACK;
+ }
+
+ /* Always do write dirty-tracking and COW on PTE level. */
+ if (write && (READ_ONCE(vbo->dirty) || is_cow_mapping))
+ return VM_FAULT_FALLBACK;
+
+ ret = ttm_bo_vm_reserve(bo, vmf);
+ if (ret)
+ return ret;
+
+ if (vbo->dirty) {
+ pgoff_t allowed_prefault;
+ unsigned long page_offset;
+
+ page_offset = vmf->pgoff -
+ drm_vma_node_start(&bo->base.vma_node);
+ if (page_offset >= bo->num_pages ||
+ vmw_resources_clean(vbo, page_offset,
+ page_offset + PAGE_SIZE,
+ &allowed_prefault)) {
+ ret = VM_FAULT_SIGBUS;
+ goto out_unlock;
+ }
+
+ /*
+ * Write protect, so we get a new fault on write, and can
+ * split.
+ */
+ prot = vm_get_page_prot(vma->vm_flags & ~VM_SHARED);
+ } else {
+ prot = vm_get_page_prot(vma->vm_flags);
+ }
+
+ ret = ttm_bo_vm_fault_reserved(vmf, prot, 1, fault_page_size);
+ if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT))
+ return ret;
+
+out_unlock:
+ dma_resv_unlock(bo->base.resv);
+
+ return ret;
+}
+#endif
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_glue.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_glue.c
index aa7e50f63b94..3c03b1746661 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_glue.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_glue.c
@@ -34,7 +34,10 @@ int vmw_mmap(struct file *filp, struct vm_area_struct *vma)
.page_mkwrite = vmw_bo_vm_mkwrite,
.fault = vmw_bo_vm_fault,
.open = ttm_bo_vm_open,
- .close = ttm_bo_vm_close
+ .close = ttm_bo_vm_close,
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+ .huge_fault = vmw_bo_vm_huge_fault,
+#endif
};
struct drm_file *file_priv = filp->private_data;
struct vmw_private *dev_priv = vmw_priv(file_priv->minor->dev);
--
2.21.1