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// SPDX-License-Identifier: MIT
/*
* Copyright © 2017 Intel Corporation
*/
#include <linux/fs.h>
#include <linux/mount.h>
#include <linux/fs_context.h>
#include "i915_drv.h"
#include "i915_gemfs.h"
#include "i915_utils.h"
static int add_param(struct fs_context *fc, const char *key, const char *val)
{
return vfs_parse_fs_string(fc, key, val, strlen(val));
}
void i915_gemfs_init(struct drm_i915_private *i915)
{
struct file_system_type *type;
struct fs_context *fc;
struct vfsmount *gemfs;
int ret;
/*
* 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 on platforms which benefit from it, or to
* offset the overhead of iommu lookups, where with latter it is a net
* win even on platforms which would otherwise see some performance
* regressions such a slow reads issue on Broadwell and Skylake.
*/
if (GRAPHICS_VER(i915) < 11 && !i915_vtd_active(i915))
return;
if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
goto err;
type = get_fs_type("tmpfs");
if (!type)
goto err;
fc = fs_context_for_mount(type, SB_KERNMOUNT);
if (IS_ERR(fc))
goto err;
ret = add_param(fc, "source", "tmpfs");
if (!ret)
ret = add_param(fc, "huge", "within_size");
if (!ret)
gemfs = fc_mount_longterm(fc);
put_fs_context(fc);
if (ret)
goto err;
i915->mm.gemfs = gemfs;
drm_info(&i915->drm, "Using Transparent Hugepages\n");
return;
err:
drm_notice(&i915->drm,
"Transparent Hugepage support is recommended for optimal performance%s\n",
GRAPHICS_VER(i915) >= 11 ? " on this platform!" :
" when IOMMU is enabled!");
}
void i915_gemfs_fini(struct drm_i915_private *i915)
{
kern_unmount(i915->mm.gemfs);
}
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