On Fri, 28 Nov 2025 19:52:50 +0100 Loïc Molinari <[email protected]> wrote:
> Introduce the 'panthor.transparent_hugepage' boolean module parameter > (false by default). When the parameter is set to true, a new tmpfs > mountpoint is created and mounted using the 'huge=within_size' > option. It's then used at GEM object creation instead of the default > 'shm_mnt' mountpoint in order to enable Transparent Hugepage (THP) for > the object (without having to rely on a system wide parameter). > > v3: > - use huge tmpfs mountpoint in drm_device > > v4: > - fix builds with CONFIG_TRANSPARENT_HUGEPAGE=n > - clean up mountpoint creation error handling > - print negative error value > > v5: > - use drm_gem_has_huge_tmp() helper > - get rid of CONFIG_TRANSPARENT_HUGEPAGE ifdefs > > v9: > - replace drm_gem_has_huge_tmp() by drm_gem_get_huge_tmp() > > Signed-off-by: Loïc Molinari <[email protected]> > Reviewed-by: Boris Brezillon <[email protected]> > --- > drivers/gpu/drm/panthor/panthor_device.c | 3 +++ > drivers/gpu/drm/panthor/panthor_drv.c | 7 +++++++ > drivers/gpu/drm/panthor/panthor_drv.h | 9 +++++++++ > drivers/gpu/drm/panthor/panthor_gem.c | 18 ++++++++++++++++++ > drivers/gpu/drm/panthor/panthor_gem.h | 2 ++ > 5 files changed, 39 insertions(+) > create mode 100644 drivers/gpu/drm/panthor/panthor_drv.h > > diff --git a/drivers/gpu/drm/panthor/panthor_device.c > b/drivers/gpu/drm/panthor/panthor_device.c > index e133b1e0ad6d..2979ee0e52c2 100644 > --- a/drivers/gpu/drm/panthor/panthor_device.c > +++ b/drivers/gpu/drm/panthor/panthor_device.c > @@ -18,6 +18,7 @@ > #include "panthor_devfreq.h" > #include "panthor_device.h" > #include "panthor_fw.h" > +#include "panthor_gem.h" > #include "panthor_gpu.h" > #include "panthor_hw.h" > #include "panthor_mmu.h" > @@ -294,6 +295,8 @@ int panthor_device_init(struct panthor_device *ptdev) > if (ret) > goto err_unplug_fw; > > + panthor_gem_init(ptdev); > + > /* ~3 frames */ > pm_runtime_set_autosuspend_delay(ptdev->base.dev, 50); > pm_runtime_use_autosuspend(ptdev->base.dev); > diff --git a/drivers/gpu/drm/panthor/panthor_drv.c > b/drivers/gpu/drm/panthor/panthor_drv.c > index d1d4c50da5bf..55dbda6dbf9c 100644 > --- a/drivers/gpu/drm/panthor/panthor_drv.c > +++ b/drivers/gpu/drm/panthor/panthor_drv.c > @@ -1559,6 +1559,7 @@ static const struct file_operations > panthor_drm_driver_fops = { > .read = drm_read, > .llseek = noop_llseek, > .mmap = panthor_mmap, > + .get_unmapped_area = drm_gem_get_unmapped_area, > .show_fdinfo = drm_show_fdinfo, > .fop_flags = FOP_UNSIGNED_OFFSET, > }; > @@ -1626,6 +1627,12 @@ static const struct drm_driver panthor_drm_driver = { > #endif > }; > > +#ifdef CONFIG_TRANSPARENT_HUGEPAGE > +bool panthor_transparent_hugepage; > +module_param_named(transparent_hugepage, panthor_transparent_hugepage, bool, > 0400); > +MODULE_PARM_DESC(transparent_hugepage, "Use a dedicated tmpfs mount point > with Transparent Hugepage enabled (false = default)"); On a second thought, I wonder if this shouldn't be an opt-out param (which is what V3D does, BTW). What's the downside of enabling THP if we have a fallback for cases where memory is too fragmented to get huge pages at allocation time? > +#endif > + > static int panthor_probe(struct platform_device *pdev) > { > struct panthor_device *ptdev; > diff --git a/drivers/gpu/drm/panthor/panthor_drv.h > b/drivers/gpu/drm/panthor/panthor_drv.h > new file mode 100644 > index 000000000000..79dccd289881 > --- /dev/null > +++ b/drivers/gpu/drm/panthor/panthor_drv.h > @@ -0,0 +1,9 @@ > +// SPDX-License-Identifier: GPL-2.0 or MIT > +/* Copyright 2025 Amazon.com, Inc. or its affiliates */ > + > +#ifndef __PANTHOR_DRV_H__ > +#define __PANTHOR_DRV_H__ > + > +extern bool panthor_transparent_hugepage; > + > +#endif > diff --git a/drivers/gpu/drm/panthor/panthor_gem.c > b/drivers/gpu/drm/panthor/panthor_gem.c > index 10d255cccc09..7ae07a9bc996 100644 > --- a/drivers/gpu/drm/panthor/panthor_gem.c > +++ b/drivers/gpu/drm/panthor/panthor_gem.c > @@ -1,6 +1,7 @@ > // SPDX-License-Identifier: GPL-2.0 or MIT > /* Copyright 2019 Linaro, Ltd, Rob Herring <[email protected]> */ > /* Copyright 2023 Collabora ltd. */ > +/* Copyright 2025 Amazon.com, Inc. or its affiliates */ > > #include <linux/cleanup.h> > #include <linux/dma-buf.h> > @@ -12,10 +13,27 @@ > #include <drm/panthor_drm.h> > > #include "panthor_device.h" > +#include "panthor_drv.h" > #include "panthor_fw.h" > #include "panthor_gem.h" > #include "panthor_mmu.h" > > +void panthor_gem_init(struct panthor_device *ptdev) > +{ > + int err; > + > + if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && > + !panthor_transparent_hugepage) > + return; > + > + err = drm_gem_huge_mnt_create(&ptdev->base, "within_size"); > + if (drm_gem_get_huge_mnt(&ptdev->base)) > + drm_info(&ptdev->base, "Using Transparent Hugepage\n"); > + else if (err) > + drm_warn(&ptdev->base, "Can't use Transparent Hugepage (%d)\n", > + err); > +} > + > #ifdef CONFIG_DEBUG_FS > static void panthor_gem_debugfs_bo_init(struct panthor_gem_object *bo) > { > diff --git a/drivers/gpu/drm/panthor/panthor_gem.h > b/drivers/gpu/drm/panthor/panthor_gem.h > index 80c6e24112d0..2eefe9104e5e 100644 > --- a/drivers/gpu/drm/panthor/panthor_gem.h > +++ b/drivers/gpu/drm/panthor/panthor_gem.h > @@ -136,6 +136,8 @@ struct panthor_gem_object *to_panthor_bo(struct > drm_gem_object *obj) > return container_of(to_drm_gem_shmem_obj(obj), struct > panthor_gem_object, base); > } > > +void panthor_gem_init(struct panthor_device *ptdev); > + > struct drm_gem_object *panthor_gem_create_object(struct drm_device *ddev, > size_t size); > > int
