1 // SPDX-License-Identifier: MIT 2 /* 3 * Copyright © 2017 Intel Corporation 4 */ 5 6 #include <linux/fs.h> 7 #include <linux/mount.h> 8 #include <linux/fs_context.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 struct file_system_type *type; 17 struct fs_context *fc; 18 struct vfsmount *gemfs; 19 int ret; 20 21 /* 22 * By creating our own shmemfs mountpoint, we can pass in 23 * mount flags that better match our usecase. 24 * 25 * One example, although it is probably better with a per-file 26 * control, is selecting huge page allocations ("huge=within_size"). 27 * However, we only do so on platforms which benefit from it, or to 28 * offset the overhead of iommu lookups, where with latter it is a net 29 * win even on platforms which would otherwise see some performance 30 * regressions such a slow reads issue on Broadwell and Skylake. 31 */ 32 33 if (GRAPHICS_VER(i915) < 11 && !i915_vtd_active(i915)) 34 return; 35 36 if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) 37 goto err; 38 39 type = get_fs_type("tmpfs"); 40 if (!type) 41 goto err; 42 43 fc = fs_context_for_mount(type, SB_KERNMOUNT); 44 if (IS_ERR(fc)) 45 goto err; 46 ret = vfs_parse_fs_string(fc, "source", "tmpfs"); 47 if (!ret) 48 ret = vfs_parse_fs_string(fc, "huge", "within_size"); 49 if (!ret) 50 gemfs = fc_mount_longterm(fc); 51 put_fs_context(fc); 52 if (ret) 53 goto err; 54 55 i915->mm.gemfs = gemfs; 56 drm_info(&i915->drm, "Using Transparent Hugepages\n"); 57 return; 58 59 err: 60 drm_notice(&i915->drm, 61 "Transparent Hugepage support is recommended for optimal performance%s\n", 62 GRAPHICS_VER(i915) >= 11 ? " on this platform!" : 63 " when IOMMU is enabled!"); 64 } 65 66 void i915_gemfs_fini(struct drm_i915_private *i915) 67 { 68 kern_unmount(i915->mm.gemfs); 69 } 70