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/*
* SPDX-License-Identifier: MIT
*
* Copyright © 2017 Intel Corporation
*/
#include <linux/fs.h>
#include <linux/mount.h>
#include "i915_drv.h"
#include "i915_gemfs.h"
int i915_gemfs_init(struct drm_i915_private *i915)
{
char huge_opt[] = "huge=within_size"; /* r/w */
struct file_system_type *type;
struct vfsmount *gemfs;
char *opts;
type = get_fs_type("tmpfs");
if (!type)
return -ENODEV;
/*
* By creating our own shmemfs mountpoint, we can pass in
* mount flags that better match our usecase.
*
* One example, although it is probably better with a per-file
* control, is selecting huge page allocations ("huge=within_size").
* However, we only do so to offset the overhead of iommu lookups
* due to bandwidth issues (slow reads) on Broadwell+.
*/
opts = NULL;
if (intel_vtd_active(i915)) {
if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
opts = huge_opt;
drm_info(&i915->drm,
"Transparent Hugepage mode '%s'\n",
opts);
} else {
drm_notice(&i915->drm,
"Transparent Hugepage support is recommended for optimal performance when IOMMU is enabled!\n");
}
}
gemfs = vfs_kern_mount(type, SB_KERNMOUNT, type->name, opts);
if (IS_ERR(gemfs))
return PTR_ERR(gemfs);
i915->mm.gemfs = gemfs;
return 0;
}
void i915_gemfs_fini(struct drm_i915_private *i915)
{
kern_unmount(i915->mm.gemfs);
}
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