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1/*2 * SPDX-License-Identifier: MIT3 *4 * Copyright © 2017 Intel Corporation5 */6 7#include <linux/fs.h>8#include <linux/mount.h>9 10#include "i915_drv.h"11#include "i915_gemfs.h"12#include "i915_utils.h"13 14void i915_gemfs_init(struct drm_i915_private *i915)15{16 char huge_opt[] = "huge=within_size"; /* r/w */17 struct file_system_type *type;18 struct vfsmount *gemfs;19 20 /*21 * By creating our own shmemfs mountpoint, we can pass in22 * mount flags that better match our usecase.23 *24 * One example, although it is probably better with a per-file25 * control, is selecting huge page allocations ("huge=within_size").26 * However, we only do so on platforms which benefit from it, or to27 * offset the overhead of iommu lookups, where with latter it is a net28 * win even on platforms which would otherwise see some performance29 * regressions such a slow reads issue on Broadwell and Skylake.30 */31 32 if (GRAPHICS_VER(i915) < 11 && !i915_vtd_active(i915))33 return;34 35 if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))36 goto err;37 38 type = get_fs_type("tmpfs");39 if (!type)40 goto err;41 42 gemfs = vfs_kern_mount(type, SB_KERNMOUNT, type->name, huge_opt);43 if (IS_ERR(gemfs))44 goto err;45 46 i915->mm.gemfs = gemfs;47 drm_info(&i915->drm, "Using Transparent Hugepages\n");48 return;49 50err:51 drm_notice(&i915->drm,52 "Transparent Hugepage support is recommended for optimal performance%s\n",53 GRAPHICS_VER(i915) >= 11 ? " on this platform!" :54 " when IOMMU is enabled!");55}56 57void i915_gemfs_fini(struct drm_i915_private *i915)58{59 kern_unmount(i915->mm.gemfs);60}61