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Subject[PATCH v4 8/9] drm/vmwgfx: Introduce a huge page aligning TTM range manager
Date
From: Thomas Hellstrom <thellstrom@vmware.com>

Using huge page-table entries requires that the physical address of the
start of a buffer object is huge page size aligned.
Make a special version of the TTM range manager that accomplishes this,
but falls back to a smaller page size alignment (PUD->PMD, PMD->NORMAL)
to avoid eviction.
If other drivers want to use it in the future, it can be made a
TTM generic helper. Note that drivers can force eviction for a certain
alignment by assigning the TTM GPU alignment correspondingly.

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/Makefile | 1 +
drivers/gpu/drm/vmwgfx/vmwgfx_drv.h | 7 ++
drivers/gpu/drm/vmwgfx/vmwgfx_thp.c | 166 ++++++++++++++++++++++++++++
3 files changed, 174 insertions(+)
create mode 100644 drivers/gpu/drm/vmwgfx/vmwgfx_thp.c

diff --git a/drivers/gpu/drm/vmwgfx/Makefile b/drivers/gpu/drm/vmwgfx/Makefile
index c877a21a0739..421dd2a497a5 100644
--- a/drivers/gpu/drm/vmwgfx/Makefile
+++ b/drivers/gpu/drm/vmwgfx/Makefile
@@ -11,4 +11,5 @@ vmwgfx-y := vmwgfx_execbuf.o vmwgfx_gmr.o vmwgfx_kms.o vmwgfx_drv.o \
vmwgfx_validation.o vmwgfx_page_dirty.o \
ttm_object.o ttm_lock.o

+vmwgfx-$(CONFIG_TRANSPARENT_HUGEPAGE) += vmwgfx_thp.o
obj-$(CONFIG_DRM_VMWGFX) := vmwgfx.o
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
index 82d86f2d2569..06267184aa0a 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_drv.h
@@ -1433,6 +1433,13 @@ vm_fault_t vmw_bo_vm_huge_fault(struct vm_fault *vmf,
enum page_entry_size pe_size);
#endif

+/* Transparent hugepage support - vmwgfx_thp.c */
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+extern const struct ttm_mem_type_manager_func vmw_thp_func;
+#else
+#define vmw_thp_func ttm_bo_manager_func
+#endif
+
/**
* VMW_DEBUG_KMS - Debug output for kernel mode-setting
*
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_thp.c b/drivers/gpu/drm/vmwgfx/vmwgfx_thp.c
new file mode 100644
index 000000000000..b7c816ba7166
--- /dev/null
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_thp.c
@@ -0,0 +1,166 @@
+// SPDX-License-Identifier: GPL-2.0 OR MIT
+/*
+ * Huge page-table-entry support for IO memory.
+ *
+ * Copyright (C) 2007-2019 Vmware, Inc. All rights reservedd.
+ */
+#include "vmwgfx_drv.h"
+#include <drm/ttm/ttm_module.h>
+#include <drm/ttm/ttm_bo_driver.h>
+#include <drm/ttm/ttm_placement.h>
+
+/**
+ * struct vmw_thp_manager - Range manager implementing huge page alignment
+ *
+ * @mm: The underlying range manager. Protected by @lock.
+ * @lock: Manager lock.
+ */
+struct vmw_thp_manager {
+ struct drm_mm mm;
+ spinlock_t lock;
+};
+
+static int vmw_thp_insert_aligned(struct drm_mm *mm, struct drm_mm_node *node,
+ unsigned long align_pages,
+ const struct ttm_place *place,
+ struct ttm_mem_reg *mem,
+ unsigned long lpfn,
+ enum drm_mm_insert_mode mode)
+{
+ if (align_pages >= mem->page_alignment &&
+ (!mem->page_alignment || align_pages % mem->page_alignment == 0)) {
+ return drm_mm_insert_node_in_range(mm, node,
+ mem->num_pages,
+ align_pages, 0,
+ place->fpfn, lpfn, mode);
+ }
+
+ return -ENOSPC;
+}
+
+static int vmw_thp_get_node(struct ttm_mem_type_manager *man,
+ struct ttm_buffer_object *bo,
+ const struct ttm_place *place,
+ struct ttm_mem_reg *mem)
+{
+ struct vmw_thp_manager *rman = (struct vmw_thp_manager *) man->priv;
+ struct drm_mm *mm = &rman->mm;
+ struct drm_mm_node *node;
+ unsigned long align_pages;
+ unsigned long lpfn;
+ enum drm_mm_insert_mode mode = DRM_MM_INSERT_BEST;
+ int ret;
+
+ node = kzalloc(sizeof(*node), GFP_KERNEL);
+ if (!node)
+ return -ENOMEM;
+
+ lpfn = place->lpfn;
+ if (!lpfn)
+ lpfn = man->size;
+
+ mode = DRM_MM_INSERT_BEST;
+ if (place->flags & TTM_PL_FLAG_TOPDOWN)
+ mode = DRM_MM_INSERT_HIGH;
+
+ spin_lock(&rman->lock);
+ if (IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)) {
+ align_pages = (HPAGE_PUD_SIZE >> PAGE_SHIFT);
+ if (mem->num_pages >= align_pages) {
+ ret = vmw_thp_insert_aligned(mm, node, align_pages,
+ place, mem, lpfn, mode);
+ if (!ret)
+ goto found_unlock;
+ }
+ }
+
+ align_pages = (HPAGE_PMD_SIZE >> PAGE_SHIFT);
+ if (mem->num_pages >= align_pages) {
+ ret = vmw_thp_insert_aligned(mm, node, align_pages, place, mem,
+ lpfn, mode);
+ if (!ret)
+ goto found_unlock;
+ }
+
+ ret = drm_mm_insert_node_in_range(mm, node, mem->num_pages,
+ mem->page_alignment, 0,
+ place->fpfn, lpfn, mode);
+found_unlock:
+ spin_unlock(&rman->lock);
+
+ if (unlikely(ret)) {
+ kfree(node);
+ } else {
+ mem->mm_node = node;
+ mem->start = node->start;
+ }
+
+ return 0;
+}
+
+
+
+static void vmw_thp_put_node(struct ttm_mem_type_manager *man,
+ struct ttm_mem_reg *mem)
+{
+ struct vmw_thp_manager *rman = (struct vmw_thp_manager *) man->priv;
+
+ if (mem->mm_node) {
+ spin_lock(&rman->lock);
+ drm_mm_remove_node(mem->mm_node);
+ spin_unlock(&rman->lock);
+
+ kfree(mem->mm_node);
+ mem->mm_node = NULL;
+ }
+}
+
+static int vmw_thp_init(struct ttm_mem_type_manager *man,
+ unsigned long p_size)
+{
+ struct vmw_thp_manager *rman;
+
+ rman = kzalloc(sizeof(*rman), GFP_KERNEL);
+ if (!rman)
+ return -ENOMEM;
+
+ drm_mm_init(&rman->mm, 0, p_size);
+ spin_lock_init(&rman->lock);
+ man->priv = rman;
+ return 0;
+}
+
+static int vmw_thp_takedown(struct ttm_mem_type_manager *man)
+{
+ struct vmw_thp_manager *rman = (struct vmw_thp_manager *) man->priv;
+ struct drm_mm *mm = &rman->mm;
+
+ spin_lock(&rman->lock);
+ if (drm_mm_clean(mm)) {
+ drm_mm_takedown(mm);
+ spin_unlock(&rman->lock);
+ kfree(rman);
+ man->priv = NULL;
+ return 0;
+ }
+ spin_unlock(&rman->lock);
+ return -EBUSY;
+}
+
+static void vmw_thp_debug(struct ttm_mem_type_manager *man,
+ struct drm_printer *printer)
+{
+ struct vmw_thp_manager *rman = (struct vmw_thp_manager *) man->priv;
+
+ spin_lock(&rman->lock);
+ drm_mm_print(&rman->mm, printer);
+ spin_unlock(&rman->lock);
+}
+
+const struct ttm_mem_type_manager_func vmw_thp_func = {
+ .init = vmw_thp_init,
+ .takedown = vmw_thp_takedown,
+ .get_node = vmw_thp_get_node,
+ .put_node = vmw_thp_put_node,
+ .debug = vmw_thp_debug
+};
--
2.21.1
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