1 /*
2 * SPDX-License-Identifier: MIT
3 *
4 * Copyright © 2017 Intel Corporation
5 */
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
i915_gemfs_init(struct drm_i915_private * i915)14 void i915_gemfs_init(struct drm_i915_private *i915)
15 {
16 #ifdef __linux__
17 char huge_opt[] = "huge=within_size"; /* r/w */
18 struct file_system_type *type;
19 struct vfsmount *gemfs;
20
21 /*
22 * By creating our own shmemfs mountpoint, we can pass in
23 * mount flags that better match our usecase.
24 *
25 * One example, although it is probably better with a per-file
26 * control, is selecting huge page allocations ("huge=within_size").
27 * However, we only do so on platforms which benefit from it, or to
28 * offset the overhead of iommu lookups, where with latter it is a net
29 * win even on platforms which would otherwise see some performance
30 * regressions such a slow reads issue on Broadwell and Skylake.
31 */
32
33 if (GRAPHICS_VER(i915) < 11 && !i915_vtd_active(i915))
34 return;
35
36 if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
37 goto err;
38
39 type = get_fs_type("tmpfs");
40 if (!type)
41 goto err;
42
43 gemfs = vfs_kern_mount(type, SB_KERNMOUNT, type->name, huge_opt);
44 if (IS_ERR(gemfs))
45 goto err;
46
47 i915->mm.gemfs = gemfs;
48 drm_info(&i915->drm, "Using Transparent Hugepages\n");
49 return;
50
51 err:
52 drm_notice(&i915->drm,
53 "Transparent Hugepage support is recommended for optimal performance%s\n",
54 GRAPHICS_VER(i915) >= 11 ? " on this platform!" :
55 " when IOMMU is enabled!");
56 #endif
57 }
58
i915_gemfs_fini(struct drm_i915_private * i915)59 void i915_gemfs_fini(struct drm_i915_private *i915)
60 {
61 #ifdef __linux__
62 kern_unmount(i915->mm.gemfs);
63 #endif
64 }
65