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