1// SPDX-License-Identifier: MIT
2/*
3 * Copyright © 2017 Intel Corporation
4 */
5
6#include <linux/fs.h>
7#include <linux/mount.h>
8#include <linux/fs_context.h>
9
10#include <drm/drm_print.h>
11
12#include "i915_drv.h"
13#include "i915_gemfs.h"
14#include "i915_utils.h"
15
16void i915_gemfs_init(struct drm_i915_private *i915)
17{
18 struct file_system_type *type;
19 struct fs_context *fc;
20 struct vfsmount *gemfs;
21 int ret;
22
23 /*
24 * By creating our own shmemfs mountpoint, we can pass in
25 * mount flags that better match our usecase.
26 *
27 * One example, although it is probably better with a per-file
28 * control, is selecting huge page allocations ("huge=within_size").
29 * However, we only do so on platforms which benefit from it, or to
30 * offset the overhead of iommu lookups, where with latter it is a net
31 * win even on platforms which would otherwise see some performance
32 * regressions such a slow reads issue on Broadwell and Skylake.
33 */
34
35 if (GRAPHICS_VER(i915) < 11 && !i915_vtd_active(i915))
36 return;
37
38 if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
39 goto err;
40
41 type = get_fs_type(name: "tmpfs");
42 if (!type)
43 goto err;
44
45 fc = fs_context_for_mount(fs_type: type, SB_KERNMOUNT);
46 if (IS_ERR(ptr: fc))
47 goto err;
48 ret = vfs_parse_fs_string(fc, key: "source", value: "tmpfs");
49 if (!ret)
50 ret = vfs_parse_fs_string(fc, key: "huge", value: "within_size");
51 if (!ret)
52 gemfs = fc_mount_longterm(fc);
53 put_fs_context(fc);
54 if (ret)
55 goto err;
56
57 i915->mm.gemfs = gemfs;
58 drm_info(&i915->drm, "Using Transparent Hugepages\n");
59 return;
60
61err:
62 drm_notice(&i915->drm,
63 "Transparent Hugepage support is recommended for optimal performance%s\n",
64 GRAPHICS_VER(i915) >= 11 ? " on this platform!" :
65 " when IOMMU is enabled!");
66}
67
68void i915_gemfs_fini(struct drm_i915_private *i915)
69{
70 kern_unmount(mnt: i915->mm.gemfs);
71}
72

source code of linux/drivers/gpu/drm/i915/gem/i915_gemfs.c