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 #include "i915_utils.h" 13 14 void i915_gemfs_init(struct drm_i915_private *i915) 15 { 16 char huge_opt[] = "huge=within_size"; /* r/w */ 17 struct file_system_type *type; 18 struct vfsmount *gemfs; 19 20 /* 21 * By creating our own shmemfs mountpoint, we can pass in 22 * mount flags that better match our usecase. 23 * 24 * One example, although it is probably better with a per-file 25 * control, is selecting huge page allocations ("huge=within_size"). 26 * However, we only do so on platforms which benefit from it, or to 27 * offset the overhead of iommu lookups, where with latter it is a net 28 * win even on platforms which would otherwise see some performance 29 * regressions such a slow reads issue on Broadwell and Skylake. 30 */ 31 32 if (GRAPHICS_VER(i915) < 11 && !i915_vtd_active(i915)) 33 return; 34 35 if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) 36 goto err; 37 38 type = get_fs_type("tmpfs"); 39 if (!type) 40 goto err; 41 42 gemfs = vfs_kern_mount(type, SB_KERNMOUNT, type->name, huge_opt); 43 if (IS_ERR(gemfs)) 44 goto err; 45 46 i915->mm.gemfs = gemfs; 47 drm_info(&i915->drm, "Using Transparent Hugepages\n"); 48 return; 49 50 err: 51 drm_notice(&i915->drm, 52 "Transparent Hugepage support is recommended for optimal performance%s\n", 53 GRAPHICS_VER(i915) >= 11 ? " on this platform!" : 54 " when IOMMU is enabled!"); 55 } 56 57 void i915_gemfs_fini(struct drm_i915_private *i915) 58 { 59 kern_unmount(i915->mm.gemfs); 60 } 61