[PATCH v5 07/12] drm/v3d: Use huge tmpfs mountpoint helpers

Loïc Molinari
2025-10-21T11:31:04Z

Make use of the new drm_gem_huge_mnt_create() and
drm_gem_has_huge_mnt() helpers to avoid code duplication. Now that
it's just a few lines long, the single function in v3d_gemfs.c is
moved into v3d_gem.c.

v3:
- use huge tmpfs mountpoint in drm_device
- move v3d_gemfs.c into v3d_gem.c

v4:
- clean up mountpoint creation error handling

v5:
- fix CONFIG_TRANSPARENT_HUGEPAGE check
- use drm_gem_has_huge_mnt() helper

Signed-off-by: Loïc Molinari <loic.molinari@collabora.com>
---
drivers/gpu/drm/v3d/Makefile | 3 +-
drivers/gpu/drm/v3d/v3d_bo.c | 5 ++-
drivers/gpu/drm/v3d/v3d_drv.c | 2 +-
drivers/gpu/drm/v3d/v3d_drv.h | 11 +-----
drivers/gpu/drm/v3d/v3d_gem.c | 27 +++++++++++++--
drivers/gpu/drm/v3d/v3d_gemfs.c | 60 ---------------------------------
6 files changed, 30 insertions(+), 78 deletions(-)
delete mode 100644 drivers/gpu/drm/v3d/v3d_gemfs.c

diff --git a/drivers/gpu/drm/v3d/Makefile b/drivers/gpu/drm/v3d/Makefile
index fcf710926057..b7d673f1153b 100644
--- a/drivers/gpu/drm/v3d/Makefile
+++ b/drivers/gpu/drm/v3d/Makefile
@@ -13,8 +13,7 @@ v3d-y := \
v3d_trace_points.o \
v3d_sched.o \
v3d_sysfs.o \
- v3d_submit.o \
- v3d_gemfs.o
+ v3d_submit.o

v3d-$(CONFIG_DEBUG_FS) += v3d_debugfs.o

diff --git a/drivers/gpu/drm/v3d/v3d_bo.c b/drivers/gpu/drm/v3d/v3d_bo.c
index c41476ddde68..a1e5881e8b62 100644
--- a/drivers/gpu/drm/v3d/v3d_bo.c
+++ b/drivers/gpu/drm/v3d/v3d_bo.c
@@ -112,7 +112,7 @@ v3d_bo_create_finish(struct drm_gem_object *obj)
if (IS_ERR(sgt))
return PTR_ERR(sgt);

- if (!v3d->gemfs)
+ if (!drm_gem_has_huge_mnt(obj->dev))
align = SZ_4K;
else if (obj->size >= SZ_1M)
align = SZ_1M;
@@ -148,12 +148,11 @@ struct v3d_bo *v3d_bo_create(struct drm_device *dev, struct drm_file *file_priv,
size_t unaligned_size)
{
struct drm_gem_shmem_object *shmem_obj;
- struct v3d_dev *v3d = to_v3d_dev(dev);
struct v3d_bo *bo;
int ret;

shmem_obj = drm_gem_shmem_create_with_mnt(dev, unaligned_size,
- v3d->gemfs);
+ dev->huge_mnt);
if (IS_ERR(shmem_obj))
return ERR_CAST(shmem_obj);
bo = to_v3d_bo(&shmem_obj->base);
diff --git a/drivers/gpu/drm/v3d/v3d_drv.c b/drivers/gpu/drm/v3d/v3d_drv.c
index c5a3bbbc74c5..ce82a1ceda5f 100644
--- a/drivers/gpu/drm/v3d/v3d_drv.c
+++ b/drivers/gpu/drm/v3d/v3d_drv.c
@@ -106,7 +106,7 @@ static int v3d_get_param_ioctl(struct drm_device *dev, void *data,
args->value = v3d->perfmon_info.max_counters;
return 0;
case DRM_V3D_PARAM_SUPPORTS_SUPER_PAGES:
- args->value = !!v3d->gemfs;
+ args->value = drm_gem_has_huge_mnt(dev);
return 0;
case DRM_V3D_PARAM_GLOBAL_RESET_COUNTER:
mutex_lock(&v3d->reset_lock);
diff --git a/drivers/gpu/drm/v3d/v3d_drv.h b/drivers/gpu/drm/v3d/v3d_drv.h
index 1884686985b8..99a39329bb85 100644
--- a/drivers/gpu/drm/v3d/v3d_drv.h
+++ b/drivers/gpu/drm/v3d/v3d_drv.h
@@ -158,11 +158,6 @@ struct v3d_dev {
struct drm_mm mm;
spinlock_t mm_lock;

- /*
- * tmpfs instance used for shmem backed objects
- */
- struct vfsmount *gemfs;
-
struct work_struct overflow_mem_work;

struct v3d_queue_state queue[V3D_MAX_QUEUES];
@@ -569,6 +564,7 @@ extern const struct dma_fence_ops v3d_fence_ops;
struct dma_fence *v3d_fence_create(struct v3d_dev *v3d, enum v3d_queue q);

/* v3d_gem.c */
+extern bool super_pages;
int v3d_gem_init(struct drm_device *dev);
void v3d_gem_destroy(struct drm_device *dev);
void v3d_reset_sms(struct v3d_dev *v3d);
@@ -576,11 +572,6 @@ void v3d_reset(struct v3d_dev *v3d);
void v3d_invalidate_caches(struct v3d_dev *v3d);
void v3d_clean_caches(struct v3d_dev *v3d);

-/* v3d_gemfs.c */
-extern bool super_pages;
-void v3d_gemfs_init(struct v3d_dev *v3d);
-void v3d_gemfs_fini(struct v3d_dev *v3d);
-
/* v3d_submit.c */
void v3d_job_cleanup(struct v3d_job *job);
void v3d_job_put(struct v3d_job *job);
diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c
index bb110d35f749..b6479a8a279e 100644
--- a/drivers/gpu/drm/v3d/v3d_gem.c
+++ b/drivers/gpu/drm/v3d/v3d_gem.c
@@ -258,6 +258,30 @@ v3d_invalidate_caches(struct v3d_dev *v3d)
v3d_invalidate_slices(v3d, 0);
}

+static void
+v3d_huge_mnt_init(struct v3d_dev *v3d)
+{
+ int err = 0;
+
+ /*
+ * By using a huge shmemfs mountpoint when the user wants to
+ * enable Super Pages, we can pass in mount flags that better
+ * match our usecase.
+ */
+
+ if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && super_pages)
+ err = drm_gem_huge_mnt_create(&v3d->drm, "within_size");
+
+ if (drm_gem_has_huge_mnt(&v3d->drm))
+ drm_info(&v3d->drm, "Using Transparent Hugepages\n");
+ else if (err)
+ drm_warn(&v3d->drm, "Can't use Transparent Hugepages (%d)\n",
+ err);
+ else
+ drm_notice(&v3d->drm,
+ "Transparent Hugepage support is recommended for optimal performance on this platform!\n");
+}
+
int
v3d_gem_init(struct drm_device *dev)
{
@@ -309,7 +333,7 @@ v3d_gem_init(struct drm_device *dev)
v3d_init_hw_state(v3d);
v3d_mmu_set_page_table(v3d);

- v3d_gemfs_init(v3d);
+ v3d_huge_mnt_init(v3d);

ret = v3d_sched_init(v3d);
if (ret) {
@@ -329,7 +353,6 @@ v3d_gem_destroy(struct drm_device *dev)
enum v3d_queue q;

v3d_sched_fini(v3d);
- v3d_gemfs_fini(v3d);

/* Waiting for jobs to finish would need to be done before
* unregistering V3D.
diff --git a/drivers/gpu/drm/v3d/v3d_gemfs.c b/drivers/gpu/drm/v3d/v3d_gemfs.c
deleted file mode 100644
index c1a30166c099..000000000000
--- a/drivers/gpu/drm/v3d/v3d_gemfs.c
+++ /dev/null
@@ -1,60 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0+
-/* Copyright (C) 2024 Raspberry Pi */
-
-#include <linux/fs.h>
-#include <linux/mount.h>
-#include <linux/fs_context.h>
-
-#include "v3d_drv.h"
-
-void v3d_gemfs_init(struct v3d_dev *v3d)
-{
- 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. However, we
- * only do so on platforms which benefit from it.
- */
- if (!IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE))
- goto err;
-
- /* The user doesn't want to enable Super Pages */
- if (!super_pages)
- 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 = vfs_parse_fs_string(fc, "source", "tmpfs");
- if (!ret)
- ret = vfs_parse_fs_string(fc, "huge", "within_size");
- if (!ret)
- gemfs = fc_mount_longterm(fc);
- put_fs_context(fc);
- if (ret)
- goto err;
-
- v3d->gemfs = gemfs;
- drm_info(&v3d->drm, "Using Transparent Hugepages\n");
-
- return;
-
-err:
- v3d->gemfs = NULL;
- drm_notice(&v3d->drm,
- "Transparent Hugepage support is recommended for optimal performance on this platform!\n");
-}
-
-void v3d_gemfs_fini(struct v3d_dev *v3d)
-{
- if (v3d->gemfs)
- kern_unmount(v3d->gemfs);
-}
--
2.47.3