LXR linux/drivers/gpu/drm/i915/gem/i915

   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
  13int i915_gemfs_init(struct drm_i915_private *i915)
  14{
  15        struct file_system_type *type;
  16        struct vfsmount *gemfs;
  17        char *opts;
  18
  19        type = get_fs_type("tmpfs");
  20        if (!type)
  21                return -ENODEV;
  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 to offset the overhead of iommu lookups
  30         * due to bandwidth issues (slow reads) on Broadwell+.
  31         */
  32
  33        opts = NULL;
  34        if (intel_vtd_active()) {
  35                if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
  36                        static char huge_opt[] = "huge=within_size"; /* r/w */
  37
  38                        opts = huge_opt;
  39                        drm_info(&i915->drm,
  40                                 "Transparent Hugepage mode '%s'\n",
  41                                 opts);
  42                } else {
  43                        drm_notice(&i915->drm,
  44                                   "Transparent Hugepage support is recommended for optimal performance when IOMMU is enabled!\n");
  45                }
  46        }
  47
  48        gemfs = vfs_kern_mount(type, SB_KERNMOUNT, type->name, opts);
  49        if (IS_ERR(gemfs))
  50                return PTR_ERR(gemfs);
  51
  52        i915->mm.gemfs = gemfs;
  53
  54        return 0;
  55}
  56
  57void i915_gemfs_fini(struct drm_i915_private *i915)
  58{
  59        kern_unmount(i915->mm.gemfs);
  60}
  61